Vegetable Pests of Utah

VEGETABLE PESTS OF UTAH disease and arthropod pest identification guide PUBLICATION COORDINATORS AND EDITORS Cami Cannon (Vegetable IPM Associate and Graphic Design) Marion Murray (IPM Project Leader) Editing assistance by: Diane Alston (Entomologist) Claudia Nischwitz (Plant Pathologist)

AUTHORS Cami Cannon Marion Murray Taun Beddes (diseases: herbicide damage, sunscald) Candace Schaible (insects: spinach leafminer diseases: phytophthora root/stem/crown rot)

CONTACT INFORMATION Utah State University IPM Program Dept. of Biology 5305 Old Main Hill Logan, UT 84322 (435) 797-0776 utahpests.usu.edu/IPM

FUNDING FOR THIS PUBLICATION WAS PROVIDED BY: USU Extension Grants Program CONTENTS

Preface...... 7

INSECT, MITE, AND OTHER ARTHROPOD PESTS

Aphids...... 10 Beetles...... 14 Caterpillars/Moths...... 28 Caterpillars/Moths...... 30 Earwigs...... 44 Grasshoppers...... 46 Leafhoppers...... 48 Maggots/Flies...... 52 Plant/Seed Bugs...... 64 Psyllids...... 74 Thrips...... 76 Whiteflies...... 78 Mites...... 80 Collembola/Springtails...... 90 Crustaceans...... 92 Molluscs...... 94

DISEASES AND ABIOTIC DISORDERS

Bacterial Diseases...... 98 Fungal Diseases...... 106 Fungal-Like Diseases...... 126 Nematode-Caused Diseases...... 132 Viral Diseases...... 134 Abiotic (Non-Living)...... 150 PREFACE

How to Use this Guide This guide is organized by specific insect pests and diseases within the following groups: Insects and Related Pests: Diseases Caused by: • Aphids • Bacteria • Beetles • Fungi • Caterpillars/Moths • Fungus-Like Organisms • Earwigs • Nematodes • Grasshoppers • Viruses • Leafhoppers • Abiotic (Non-Living) • Maggots/Flies • Plant/Seed Bugs • Psyllids • Thrips • Whiteflies • Mites • Symphylans • Collembola/Springtails • Crustaceans • Molluscs

Each insect pest page lists the approximate size range of adults and sometimes nymphs or larvae and should be interpreted as follows:

Dark gray line refers to lower number of size range A: refers to adult size A: 4-7 mm long Light gray line refers to higher L: refers to larva size number of size range or L: 1-9.5 mm long N: refers to nymph size Length is represented as line length from left-to-right. Width of line from top-to-bottom has no relation to insect size and was simply chosen for visibility of the line

Purpose of this Guide One of the goals of the USU IPM program is to reduce the use of broad-spectrum pesticides for pest control in favor of using more selective products that are safe on beneficial insects, water quality, and human health. Proper identification of pests in monitoring practices is crucial in accurately identifying alternative control methods. INSECT PESTS INSECT PESTS

INSECT, MITE, AND OTHER ARTHROPOD PESTS

Aphids can generally be recognized by a pair of cornicles (tailpipe-like appendages at the posterior end of the

APHIDS APHIDS body), pear-shaped body, and fairly long antennae. Cabbage Aphid (Brevicoryne brassicae)...... A: 2-2.5 mm long Corn Leaf Aphid (Rhopalosiphum maidis)...... A: 1-2.4 mm long APHIDS Green Peach Aphid (Myzus persicae)...... A: 1.8-2.1 mm long Melon/Cotton Aphid (Aphis gossypii)...... A: 1-2 mm long Potato Aphid (Macrosiphum euphorbiae)...... A: 2.4-3.6 mm long

Hosts: Wide host range including apricot, When and Where to Scout: asparagus, barley, broccoli, cabbage, • Adults first seen late May and June. catalpa, celery, some cherries, corn, • Adults and nymphs often found in cucumber, eggplant, legumes, melon, clusters on leaves or stems, but may millet, mustard green, nectarine, oats, be found singly. okra, peach, pepper, some plums, potato, • Eggs laid in fall or winter on woody Green peach aphid adults can be yellow to green in Green peach aphid winged adult. David Cappaert, Bugwood summer and vary from pale to dark-green, pink, or red pumpkin, rose, rose-of-sharon, rye, host plants, crop residue, or weeds. in fall. David Cappaert, Bugwood.org sorghum, spinach, squash, tomato, wheat, • Watch for rapidly increasing weeds such as crabgrass, foxtail, and other populations and feeding damage in ornamentals, weeds, and vegetables the late spring through early fall.

Appearance: Adults may be winged or Threat Level: Aphids are common but wingless with a pear-shaped, soft body. typically do not cause severe economic Adults and nymphs vary in color from damage unless they vector a virus or are pale to dark-green, pink, red, bluish-green, present in high populations. black, yellow, and gray, and may have a waxy covering (cabbage aphid). Top Management Techniques: • Manage nitrogen levels; avoid excess. Damage Symptoms: Adults and • Encourage natural enemies; avoid nymphs feed on hosts with piercing- toxic chemicals, provide nectar and sucking mouthparts causing stippling, pollen resources. Corn leaf aphids are bluish green or gray in color and Cabbage aphids are gray to green with a waxy covering can give plants a black, sooty appearance. Cami Cannon, Utah and short cornicles. David Cappaert, Bugwood.org chlorosis, curled leaves, and/or slow plant • Keep crop area weed-free. State University growth. Over one hundred different • For viruses transmitted by aphids: viruses can be transmitted by adults and –– Plant resistant cultivars nymphs. –– Plant early –– Remove and destroy infected Damaging Lifestage(s): Nymph, Adult plants immediately.

Life Cycle: When to Consider Treatment: • Egg | Nymph (4 stages) | Adult • If populations are high and causing (wingless or winged) economic damage. • Multiple generations per growing • If vectored virus diseases cannot be season. tolerated (e.g. seed production). • Overwinter as eggs on woody hosts • If vectored viruses occur. or crop debris. Look-alikes: potato/tomato psyllid Potato aphid adults can be pink or green in color. Joseph Melon/cotton aphid adults can be yellow, dark green, or Time for Concern: Mid-April through (winged adults), whiteflies (shed aphid Berger, Bugwood.org almost black in color. Joseph Berger, Bugwood.org the end of the growing season. skins)

10 11 INSECT PESTS INSECT PESTS

Aphid Plant Hosts by Species and Season APHIDS Common Name Winter Hosts Summer Hosts

Cabbage Aphid Only crucifers Only crucifers including broccoli, APHIDS (crop residue and cabbage, Brussels sprouts, cauliflower, weeds) and other plants in the mustard family (Brassicaceae)

Corn leaf aphid Corn, barley, Corn, barley, rye, oats, wheat, sorghum, rye, oats, wheat, millet, crabgrass, foxtail sorghum, millet, crabgrass, foxtail Aphids on a chard leaf. Cami Cannon, Utah State University Ear of corn damaged by a corn leaf aphid infestation. Cami Cannon, Utah State University Green peach Peach, apricot, Wide range including tomato, potato, aphid nectarine, and pepper, eggplant, squash, pumpkin, rarely certain cucumber, spinach, mustard greens, cherries and plums cabbage, broccoli, legumes, celery, okra, corn, and many ornamentals, weeds, and other vegetables

Melon/Cotton Catalpa, rose-of- Melon, cucumber, squash and related aphid sharon vine crops, pepper, eggplant, spinach, asparagus, okra, and many shrubs and weeds

Potato aphid Rose Potato, tomato, many of the same vegetable hosts as green peach aphid Parasitized aphid (black aphid in bottom, left corner of Chlorotic (yellowing) leaves from an aphid infestation. image) and aphid skins (upper right corner of image). Tiny white specks are aphid skins. Bonnie Bunn, Utah State Cami Cannon, Utah State University University

Aphids feed on stems and fruits and can leave behind Aphid feeding can cause leaves to curl, making pesticide stippling. Cami Cannon, Utah State University applications difficult.Cami Cannon, Utah State University

12 13 INSECT PESTS INSECT PESTS

ASPARAGUS BEETLE Asparagus Beetle (Crioceris asparagi) A: 5-6 mm long Spotted Asparagus Beetle (Crioceris duodecimpunctata) L: 1.5-8 mm long

BEETLES Hosts: asparagus When and Where to Scout: • Adults and eggs first seen in Appearance: Adults are brightly-colored approximately mid-May.

leaf beetles. Asparagus beetle has four • Adults feed on spears as soon as they BEETLES yellow spots and orange wing margins, break through the soil surface in early and a bluish black head. Spotted asparagus spring. Asparagus beetle (Crioceris asparagi) adults have dark Asparagus beetle eggs are cemented onto spears or beetle has a mostly orange body with • Larvae are found feeding on spears or bodies with red and white markings. Whitney Cranshaw Colorado ferns and are difficult to remove.Whitney Cranshaw Colorado six black spots on the forewings. Larvae burrowing into the soil (asparagus) or State University Bugwood.org State University Bugwood.org are plump and brown with a dark head berry (spotted) to pupate. capsule. • Eggs are found glued to asparagus spears. Damage Symptoms: Adults and larvae • Scout plants for presence of beetles feed with chewing mouthparts, consuming in the afternoon when they are most leaves and chewing pits in spears, causing active. distortions of growth. Large dark eggs • This pest is active from mid-May may be laid on spears. Larvae chew on through the end of July. ferns, giving them a bleached appearance and reducing photosynthesis. Sometimes, Threat Level: The most serious damage large populations of beetles can reduce is caused during the spring when adults yields and kill plants. are feeding on new spears. Occasional damage occurs during the summer, but Damaging Lifestage(s): Larva, Adult rarely stunts growth or reduces yield. The Asparagus beetle larvae are plump and brown with Asparagus beetle feeding damage on asparagus ferns. spotted asparagus beetle prefers to eat a dark head capsule. Whitney Cranshaw, Colorado State University, Whitney Cranshaw Colorado State University Bugwood.org Life Cycle: asparagus berries and rarely causes damage Bugwood.org • Egg | Larva | Pupa | Adult to leaves and spears. Larval berry feeding is • 2 generations (spotted) or 2-3 not economically important unless growing generations (asparagus) per season. asparagus for seed. • Overwinter as adults in hollow asparagus stems, or under soil clods, Top Management Techniques: loose tree bark, weeds, or other plant • Remove volunteer asparagus. debris. • Minimize weeds or other debris near asparagus. Time for Concern: Spring through • Encourage predatory beetles summer. and parasitoid wasps; avoid toxic chemicals.

When to Consider Treatment: When persistent beetle damage occurs. Spotted asparagus beetle (Crioceris duodecimpunctata) Asparagus beetle feeding damage. Whitney Cranshaw, Colorado adults are red to orange with dark spots. Bonnie Bunn, Utah State University, Bugwood.org Look-alikes: none State University

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COLORADO POTATO BEETLE Leptinotarsa decemlineata A: 8.5-11.5 mm long L: 5.5-11 mm long

BEETLES Hosts: eggplant, nicotiana, pepper, When and Where to Scout: petunia, potato, tomato, and weeds such • Adults emerge in approximately May. as belladonna, buffalo bur, henbane, horse • Larvae begin to feed on leaves in June

nettle, jimson weed, mullein, and thistle and prefer tops of plants. BEETLES • Begin scouting in mid-spring for Appearance: Adults are about the same feeding damage or the presence of size and shape as a lady beetle but with adults, eggs, or larvae. Colorado potato beetle adults have black and yellow Colorado potato beetle eggs are bright yellow-orange yellow and black stripes. Bright yellow stripes and a shape similar to ladybugs. Cami Cannon, Utah and laid in clusters on the undersides of leaves. David to orange oval-shaped eggs are laid in Threat Level: Adults and larvae can State University Cappaert, Michigan State University, Bugwood.org clusters of about 20-45 on the undersides cause great damage to potato foliage. of leaves. Larvae are reddish in color with Potatoes in the vegetative stage can tolerate a bulbous-shaped body and two rows of up to 30% defoliation, but when tubers black spots along the sides. start to bulk, plants can tolerate no more than about 10% defoliation. Damage Symptoms: Adults and larvae feed with chewing mouthparts and can Top Management Techniques: defoliate plants. Symptoms include notch • Rotate crops to non-solanaceous wounds along the leaf margin, ragged crops. injuries, and dark frass on foliage. • Keep crop area free of solanaceous weeds. Damaging Lifestage(s): Larva, Adult • Application of insecticides may be needed; resistance is common so Life Cycle: rotate insecticide groups. Colorado potato beetle Pest and Diseases Image Library Bugwood.org Colorado potato beetle larvae are bulbous in shape, reddish to orange in color, and have black spots. Cami • Egg | Larva | Pupa | Adult Cannon, Utah State University • 2-3 generations per season. When to Consider Treatment: • Overwinter as adults under plant For potatoes, when there is one adult or debris and in the soil. larva per plant early in the season or at tuber bulking/after flowering when there Time for Concern: Late April through are an average of 1.5 large larvae or adults potato vine-kill. per plant. Note: Colorado potato beetle has developed resistance to nearly every class of chemicals.

Look-alikes: none

Colorado potato beetles pupate in the soil after larval Colorado potato beetle larvae feed on potato foliage feeding. Whitney Cranshaw Colorado State University Bugwood.org resulting in defoliation. Whitney Cranshaw Colorado State University Bugwood.org

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CUCUMBER BEETLES Spotted Cucumber Beetle (Diabrotica undecimpunctata) A: 8-9 mm long Striped Cucumber Beetle (Acalymma trivittatum) L: 8-13 mm long

BEETLES Hosts: beans, corn, cucurbits (squash, When and Where to Scout: cucumbers, melons, etc.), potato, tomato, • Adults become active at temperatures small grains, other grasses including weeds, above 50°F in the spring.

and almost any type of flower • Striped cucumber beetle larvae feed BEETLES on roots and fruits touching the soil. Spotted cucumber beetle adults have yellowish green Striped cucumber beetle adults have yellow wings with wings with black spots. Bonnie Bunn, Utah State University black strips. Bonnie Bunn, Utah State University Appearance: Adults have a black head, • Adults of both species feed on stems, legs, and antennae with yellowish green leaves, flowers, and immature fruit. bodies and either black spots (spotted) or • Visually scout newly emerged or stripes (striped) on their wings. Larvae are transplanted cucurbits for feeding worm-like with white to yellowish bodies, a injury or presence of adults or eggs. brown head, and three pairs of brown legs. • Monitor with yellow sticky cards.

Damage Symptoms: Adults of both Threat Level: The striped cucumber species chew on fruits, stems, leaves, beetle causes more damage in Utah than and flowers. Larvae of only the striped the spotted cucumber beetle. Feeding Cucumber beetle eggs. Gerald Holmes California Polytechnic State Cucumber beetle larva in cantaloupe rind. Whitney Cranshaw, cucumber beetle may tunnel roots damage is of most concern when plants University at San Luis Obispo Bugwood.org Colorado State University, Bugwood.org (reducing plant stands and stunting or are in the cotyledon and first through killing plants) and may also feed on fruit third true-leaf stages. After these stages, rinds that touch the soil. several cucurbits can tolerate high levels of defoliation. Damaging Lifestage(s): Larva (striped), Adult Top Management Techniques: • Keep crop area weed free. Life Cycle: • Use floating row covers. • Egg | Larva | Pupa | Adult • Use plastic or organic mulches and • 2 generations per season. drip irrigation. • Overwinter as adults in protected • Destroy crop residues after harvest. outdoor areas. • Lure beetles away with trap crops. Cucumber beetle larval damage on a melon fruit. Diane Cucumber beetle adult scarring on a melon fruit. Diane Alston, Utah State University Alston, Utah State University • Application of insecticides may be Time for Concern: Entire season, but needed. especially when plants are small. When to Consider Treatment: When two or more beetles are found per plant on 25% of plants.

Look-alikes: western corn rootworm

Striped cucumber beetle feeding damage of a cucurbit Striped cucumber beetle infestation on a pumpkin leaf. Whitney Cranshaw, Colorado State University, Bugwood.org flower. Howard F. Schwartz, Colorado State University, Bugwood.org

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FLEA BEETLES Tribe: Alticini A: 1.6-3.2 mm long

Hosts: cole crops, edible greens, tomato, When and Where to Scout:

BEETLES eggplant, pepper, beets, potato, melons, • Adults emerge from early April to seedlings, and many weeds mid-June. • Adults can be found feeding on the

Appearance: Adults jump when foliage of host plants. BEETLES disturbed with large hind legs and their • Monitor seedlings in spring for flea metallic bodies range in color from black, beetle presence or round holes in bronze, bluish, brown, or gray, with stripes leaves. Flea beetle adults, feeding damage, and excrement on Flea beetle adults, feeding damage, and excrement on in some species. Larvae are small, white, • Use yellow sticky cards and visual kale. Cami Cannon, Utah State University arugula. Bonnie Bunn, Utah State University and worm-like with a brown head. scouting when seedlings emerge. • Inspect crops for adult flea beetle Damage Symptoms: Adults and larvae injury near field borders with feed with chewing mouthparts. Adult cruciferous weeds. feeding causes shallow pits and small, round holes in foliage, cotyledons, and Threat Level: Flea beetles are an annual stems. Larvae feed on roots and tunnel problem in the early spring and can cause into root vegetables (e.g. potatoes, carrots) cosmetic damage and/or stunt or kill leaving shallow winding grooves and small plants. Flea beetles are especially tunnels that may be filled with frass. harmful during cool springs when plants Flea beetle adult. Cami Cannon, Utah State Striped flea beetle adult.Bonnie Bunn, Flea beetle adult. Bonnie Bunn, Utah State cannot outgrow damage. Tuber flea beetle University Utah State University University Damaging Lifestage(s): Larva (tuber larvae can cause severe tunneling in potato flea beetles in potato), Adult tubers; summer management is necessary to prevent tuber damage. Life Cycle: • Egg | Larva | Pupa | Adult Top Management Techniques: • 1-3 generations per season. • Keep crop area weed free. • Overwinter as adults on weeds. • Plant trap crops. • Use row covers during seedling Time for Concern: Early April establishment. through August and early stages of plant • Eliminate old crop debris and other development. surface trash. Tuber flea beetle adult. Tuber flea beetle larval tunneling in potato tuber. • Application of insecticides may be Mike Quinn, TexasEnto.net Whitney Cranshaw, Colorado State University, Bugwood.org needed.

When to Consider Treatment: In seedlings, when there are 1-5 flea beetles per plant or defoliation reaches 10-30%. Tuber flea beetles can damage potato foliage and tubers. Art Cushman, USDA Systematics Entomology Laboratory, Bugwood. Look-alikes: none org

Flea beetles have metallic bodies and enlarged hind legs. Cami Cannon, Utah State University

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SAP BEETLES Corn Sap Beetle (Carpophilus dimidiatus)...... A: 1.6-3.2 mm long Dusky Sap Beetle (Carpophilus lugubris)...... A: 2.8-4.5 mm long Picnic Beetle (Glischrochilus quadrisignatus)...... A: 4-7 mm long BEETLES Hosts: corn, tomato, melons, most When and Where to Scout: overripe fruits and vegetables • Eggs are laid in April to early May on

or near decomposing plant material BEETLES Appearance: Adults are small, dark or in the soil. beetles with club shaped-antennae that may • Sap beetles are attracted to sweet have colored wing markings depending on corn as it tassels and often prefer Sap beetles are tiny beetles that feed on over-ripe corn Dusky sap beetle (Carpophilus lugubris) adult on melon the species. Larvae are white to cream with damaged ears. and other vegetables. Marion Murray, Utah State University fruit. Whitney Cranshaw, Colorado State University, Bugwood.org a brown head and three pairs of short legs • Adults feed on corn silk and pollen near the head. and chew on tassels. • Larvae attack and feed on kernels in Damage Symptoms: Adults and larvae the upper half of the ear. feed with chewing mouthparts on fruits and vegetables. Adults feed on corn silk Threat Level: Sap beetles are typically and pollen, and chew on tassels. Dusky sap secondary pests of corn, but can act as beetle larvae chew on developing kernels, primary pests if populations are high. although there is rarely any external Super sweet corn varieties and damaged or evidence of infestation. Sap beetles are overripe crops are particularly susceptible attracted to ripe, damage, or overripe fruits to sap beetle damage. and vegetables. Top Management Techniques: Picnic beetle (Glischrochilus quadrisignatus) Don Magnusson Corn sap beetle (Carpophilus dimidiatus) adult. Damaging Lifestage(s): Larva, Adult • Prevent damage from other primary Pest and Diseases Image Library, Bugwood.org pests (corn earworm, European Life Cycle: earwig). • Egg | Larva | Pupa | Adult • Harvest host crops promptly when • Several generations per season. ripe; remove decayed and damaged • Overwinter as adults in protected corn ears and fruits. places such as decaying vegetation, • Use bait/pheromone traps to debris, or in soils. monitor and reduce populations. • Disk or plow crops immediately after Time for Concern: When corn is harvest. tasseling or host crops are overripe or damaged. When to Consider Treatment: Insecticides are generally inappropriate because sap beetles invade crops near Sap beetle larvae damaging kernels of an ear of corn. Dusky sap beetle larvae on corn. Marion Murray, Utah State harvest and control with insecticides is Eugene E. Nelson, Bugwood.org University difficult because adults and larvae are protected inside the ear.

Look-alikes: none

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WESTERN CORN ROOTWORM Diabrotica virgifera A: 4.4-6.8 mm long L: 3.2-13 mm long

BEETLES Hosts: Larvae feed solely on roots of When and Where to Scout: corn and a few related grasses while adults • Monitor adults with yellow sticky feed on corn silk, flowers (especially traps; check and replace traps weekly.

cucurbits), and foliage of a wide variety of • Larvae are present from early June to BEETLES plants. mid-July. • Adults are present from mid-July to

Appearance: Adults are small beetles mid-August. Western corn rootworm adults. Whitney Cranshaw, Colorado State Western corn rootworm adult on pumpkin rind. Jim with yellow-green bodies and three black University Jasinski, Ohio State University Extension, Bugwood.org stripes on the forewings. Larvae are creamy Threat Level: Larval feeding is the most white with a brown head capsule. damaging, while adult feeding will not typically result in economic loss. Damage Symptoms: Larvae feed with chewing mouthparts on roots causing Top Management Techniques: browning, lesions, tunneling, curved • Rotate corn crops. cornstalks (goosenecking), yield losses, and • Plant early. susceptibility to root and stalk diseases. • Select varieties with vigorous root Adults feed with chewing mouthparts, systems that are well adapted to the resulting in poorly-filled ears. area.

Western corn rootworm life cycle. Jim Kalisch UNLorg Damaging Lifestage(s): Larva, Adult When to Consider Treatment: If adults exceed 35 per trap per week in Life Cycle: continuous corn (fields where corn is • Egg | Larva | Pupa | Adult planted for two or more consecutive years), • 1 generation per year. treat the following year. • Overwinter as eggs in the soil. Look-alikes: cucumber beetles Time for Concern: Early June to mid- July.

Western corn rootworm damage. Eric Burkness, Bugwood.org

"Gooseneck" symptom caused by western corn rootworm. Bryan Jensen, University of Georgia, Bugwood.org

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WIREWORMS Ctenicera spp. A: 6.4-12.7 mm long Limonius spp. L: 12.7-38 mm long

BEETLES Hosts: Seeds and roots of a wide variety When and Where to Scout: of plants. Most commonly affected root • Adults emerge in late April to early crops include potato, carrot and sweet May in northern Utah.

potato. • Inspect the soil surface for BEETLES wireworms after plowing or disking Wireworm damage to a carrot. Doug Young Professor Emeritus of Wireworm pupa and larva. Ontario Ministry of Agriculture, Food and Appearance: Adults are known as click fields. Washington State University Rural Affairs (OMAFRA) beetles (a hinge-like mechanism between • Baits (carrots, untreated corn or the thorax and abdomen creates a clicking wheat seed, ground whole wheat noise) with a black to brown hard-shell four) can be used to detect wireworm body. Larvae are wiry with a light brown, larvae. Place two bait stations per slightly hard, elongate body. acre, 4-6 inches deep in the soil, when soil temperatures are at 50°F and Damage Symptoms: Larvae tunnel check for wireworms just prior to through germinating seeds, roots, and planting. other belowground plant parts. Tunneling degrades the quality of root crops and Threat Level: Wireworm injury is seedlings may be killed. uncommon, but there have been a few problems in Utah. Once present in a field, Damaging Lifestage(s): Larva wireworms can be difficult to eradicate.

Life Cycle: Top Management Techniques:

• Egg | Larva | Pupa | Adult • Crop rotation. Wireworm adult. Pavel Kirillov • Variable generations per year. • Remove dead plants and tubers • Overwinter as adults in the soil. throughout the season and at harvest. • Maintain healthy soils. Time for Concern: Throughout the season. When to Consider Treatment: If there are one or more larvae per bait station.

Look-alikes: none Wireworm adult, eggs, larva, pupa, and damage to carrot, potato, and onion. Art Cushman, USDA Systematics Entomology Laboratory, Bugwood.org

Wireworm damage to potato tuber. Ontario Crop IPM, OMAFRA

26 27 INSECT PESTS INSECT PESTS

ARMYWORM Beet armyworm...... A: 25-30 mm wingspan...... L: 1-30 mm (Spodoptera exigua) Bertha armyworm...... A: 40 mm wingspan...... L: 3-40 mm (Mamestra configurata) Fall armyworm...... A: 31-38 mm wingspan...... L: 1.7-34.2 mm (Spodoptera frugiperda) Western yellowstriped armyworm..... A: 34-41 mm wingspan...... L: 2-40 mm (Spodoptera praefica)

Beet armyworm adult. Paul Harris, Bugwood.org Bertha armyworm adult. Hanna Royals, Screening Aids, USDA APHIS

CATERPILLARS ITP, Bugwood.org

/MOTHS Hosts: alfalfa, artichoke, asparagus, beans, When and Where to Scout: beets, broccoli, Brussels sprouts, cabbage, • Monitor adults (fall and beet carrot, cauliflower, celery, collards, corn, armyworms) with pheromone traps, cucumber, garlic, kale, lettuce, melon, starting in June. /MOTHS

onion, parsley, parsnip, pea, pepper, potato, • Eggs are found on leaves of crops or CATERPILLARS radish, rhubarb, spinach, sweet potato, weeds. Swiss chard, tomato, grassy weeds and • Young larvae are found near the egg crops, and many herbaceous ornamentals mass, or in groups on host plants. and weeds • Maturing larvae disperse and move towards the center of the plant, or Appearance: Adults are mottled gray may be seen in the soil. and brown moths with light-colored Fall armyworm adult. Robert J. Bauernfeind Kansas State University Western yellowstriped armyworm adult. Jim Moore markings. Larvae vary in color from tan, Threat Level: Corn may be regularly Bugwood.org green, and almost black. attacked while other vegetables are only occasionally attacked depending on the Damage Symptoms: Larvae feed on armyworm species and host plant. In leaves with chewing mouthparts, causing dense, crowded populations, armyworms skeletonized foliage, irregular holes, migrate and may completely defoliate shredded leaves, or defoliation. Larvae may crops. tunnel into corn ears, bore into the head of leafy vegetables, and chew into stems, Top Management Techniques: flower buds, and sometimes upper plant • Keep crop area weed-free (especially Beet armyworm larva. John Capinera, University of Florida, Bugwood.org Bertha armyworm larva. David Gent, USDA Agricultural Research Service, Bugwood.org roots. grassy weeds). • Till in the fall. Damaging Lifestage(s): Larva • Application of insecticides; Bt and spinosad are effective on young Life Cycle: caterpillars. • Egg | Larva (6-9 stages) | Pupa | Adult (moth) When to Consider Treatment: • 1-3 generations per growing season. • For corn seedlings, if 25% of plants show damage and live larvae are still • Overwinter as pupae in the soil. Fall armyworm larvae have a distinct inverted 'Y' on the Western yellowstriped armyworm larva. Khazelbaker present. front of the head. Phil Sloderbeck, Kansas State University, Bugwood.org Time for Concern: Mid-July through • If armyworms move into fields and September. infest crop areas.

Look-alikes: cutworms, corn earworm 28 29 INSECT PESTS INSECT PESTS

ARMYWORM (CONT.) Beet armyworm...... A: 25-30 mm wingspan...... L: 1-30 mm (Spodoptera exigua) Bertha armyworm...... A: 40 mm wingspan...... L: 3-40 mm (Mamestra configurata) Fall armyworm...... A: 31-38 mm wingspan...... L: 1.7-34.2 mm (Spodoptera frugiperda) Western yellowstriped armyworm..... A: 34-41 mm wingspan...... L: 2-40 mm (Spodoptera praefica) CATERPILLARS

/MOTHS Beet armyworm damage to sweet pepper. David Riley, Armyworm damage. David Riley, University of Georgia, bugwood.org University of Georgia, Bugwood.org /MOTHS CATERPILLARS

Fall armyworm pupa. Matt Bertone North Caroline State University 2014 Fall armyworm egg mass. Ronald Smith, Auburn University, Bugwood. org

Beet armyworm damage on onion. Bob Hammon, Colorado State Fall armyworm larva in corn whorl and damage. University University, Bugwood.org State University 2014 of Georgia , University of Georgia, Bugwood.org

Beet armyworm egg mass. Ronald Smith, Auburn University, Bugwood. Beet armyworm egg mass hatching. Alton N. Sparks, Jr., University org of Georgia, Bugwood.org

Fall armyworm damage to corn ear. Billy R. Wiseman, USDA Beet armyworm larva, excrement, and leaf injury to Agricultural Research Service, Bugwood.org pepper. Whitney Cranshaw, Colorado State University, Bugwood.org

30 31 INSECT PESTS INSECT PESTS

CABBAGE LOOPER Trichoplusia ni A: 33-38 mm wingspan L: 30.5-40.6 mm long

Hosts: brassicas, beet, celery, cucumber, When and Where to Scout: lettuce, lima bean, parsnip, pea, pepper, • Monitor with pheromone traps potato, snap bean, spinach, squash, sweet starting in mid-July. potato, tomato, nasturtium, carnation, • Scout plantings for eggs and and weeds such as curly dock, dandelion, larvae and feeding damage on the

CATERPILLARS lambsquarters, and wild lettuce undersides of leaves (especially /MOTHS innermost leaves). Cabbage looper adult moth; note the silvery figure-8 on Cabbage looper eggs are small, yellow, and round. Whitney Appearance: Adults are grayish brown • Examine at least 10% of the crop, the front wings. Keith Naylor, Bugwood.org Cranshaw, Colorado State University semi-nocturnal moths with a silver “8” checking random interior and edge

on each wing. Caterpillar larvae arch their areas. /MOTHS

body into a loop as they move and are pale CATERPILLARS to dark green with few sparse hairs on Threat Level: Cabbage looper is a their body. Pupae form a fuzzy cocoon on common pest of home gardens and has leaves, plant debris, and soil. a broad host range. Feeding damage and contamination (larval body or frass) are of Damage Symptoms: Larvae feed with most concern in brassicas. chewing mouthparts causing “window panes” and/or ragged holes in leaves and Top Management Techniques: sometimes serious defoliation. Larval • Use row covers. bodies and frass contaminate harvested • Remove plant debris at the end of the brassicas. growing season. • Hand-pick and destroy larvae. Close-up of cabbage looper egg. Whitney Cranshaw, Colorado Cabbage looper larva or caterpillar; note the loop-like Damaging Lifestage(s): Larva • Application of insecticides; Bt and State University, Bugwood.org crawling. Bonnie Bunn, Utah State University spinosad are effective. Life Cycle: • Egg | Larva | Pupa | Adult When to Consider Treatment: • 1-3 generations per season. • For head-forming plants, when 1 • Overwinter as pupae on leaves, plant larva has been found in 25-50 plants debris, and soil. or when 10% of plants have at least 1 larva. Time for Concern: Mid-July through • Non-head forming plants can tolerate harvest. Strong winds from southern a higher population. locations may suddenly increase populations while cold, wet weather will Look-alikes: diamondback moth (larva, reduce populations. Damage typically pupa), imported cabbageworm (larva) occurs after head formation begins in brassicas, but caterpillars sometimes attack seedling plants. Cabbage looper pupa exposed from cocoon. Whitney Cabbage looper feeding damage. John C. French Sr., Retired, Cranshaw, Colorado State University Universities:Auburn, GA, Clemson and U of MO, Bugwood.org

32 33 INSECT PESTS INSECT PESTS

CORN EARWORM (TOMATO FRUITWORM) Helicoverpa zea A: 38 mm wingspan L: 1.5-38 mm long

Hosts: artichoke, asparagus, cabbage, When and Where to Scout: cantaloupe, collards, corn, cucumber, • Dispersing adults are first seen as eggplant, lettuce, lima bean, melon, okra, early as May or as late as August. pea, pepper, potato, pumpkin, snap bean, • In corn, monitor adult moths with a spinach, squash, sweet potato, tomato, Heliothis trap.

CATERPILLARS watermelon, weeds such as common –– Place trap by early June along /MOTHS mallow, lambsquarters, pigweed, purslane, edge of corn field, and move it Corn earworm adult. Utah State University Corn earworm eggs on corn silk. ragweed, sunflower, other weeds, and many throughout the season to keep it field crops, fruits, and flowers near fresh corn silk.

–– Check twice weekly until first /MOTHS

Appearance: Adults are tannish brown catch, then check daily for best CATERPILLARS moths that are most active at dusk. Larvae results. are brown-headed caterpillars with green, brown, or black bodies. Threat Level: Corn earworm is the most destructive insect pest of sweet corn Damage Symptoms: Larvae chew in Utah. Corn is strongly preferred, but into corn kernels near the ear tip, leave tomato and pepper may also be attacked. behind frass, and/or chew on silks, decreasing pollination and leading to Top Management Techniques: poor ear-fill. Larvae also feed on leaves • Plant resistant corn varieties with and reproductive structures of other long, tight husks. host crops and can bore deeply into fruit • Plant corn early and harvest before causing premature fruit ripening. 1300 DD50 (about Jul 20-Aug 5). Typically, corn ears never have more than one corn Corn earworm larva and corn damage. Utah State University • Till soil in the fall. earworm. Damaging Lifestage(s): Larva • Application of insecticides in corn, based on trap catches (apply before Life Cycle: larvae enter corn ears). • Egg | Larva | Pupa | Adult • 3 generations per year in northern When to Consider Treatment: Utah. In corn, calculate average # of moths • 4 or more generations per year in caught per night in Heliothis trap and southern Utah. follow threshold guidelines found in the • Overwinter as pupae in the soil in Utah Vegetable Production and Pest Management central and southern Utah. Guide to decide when to take treatment action. Time for Concern: Mid-July through harvest. Look-alikes: cutworms, armyworms

Corn earworm feeding through corn husk. Utah State Corn earworm feeding damage. Utah State University University

34 35 INSECT PESTS INSECT PESTS

CUTWORMS Army Cutworm...... A: 35-45 mm wingspan ...... L: 1.5-50 mm (Euxoa auxiliaris) Black Cutworm...... A: 40-55 mm wingspan ...... L: 3-50 mm (Agotis ipsilon) Glassy Cutworm...... A: 35-40 mm wingspan ...... L: 2-40 mm (Crymodes devastator) Black cutworm larva. Adam Sisson, Iowa State University, Bugwood.org Pale Western Cutworm.... A: 30-38 mm wingspan ...... L: 3.2-38 mm (Agrotis orthogonia) Variegated Cutworm...... A: 38-56 mm wingspan ...... L: 2-45 mm Army cutworm larva. Frank Peairs, Colorado State University, Bugwood. CATERPILLARS (Peridroma saucia) org /MOTHS

Hosts: Nearly all vegetables, alfalfa, When and Where to Scout: clover, sorghum, strawberry, sometimes • Larvae can be seen as early as late grains and grasses, and weeds such as curly January into April. /MOTHS dock, lambsquarters, pigweed • Look for seedlings (especially beans) CATERPILLARS cut off near the soil and use a trowel Pale western cutworm larva. Frank Peairs, Colorado State University, Appearance: Larvae are dull gray to to look for larvae in the soil nearby. Bugwood.org brown caterpillars that curl into a ‘C’ when • Look for wilted plants that may disturbed. indicate stem feeding injury. • Later in the season, monitor plants Damage Symptoms: Larvae feed with for foliage damage. Glassy cutworm larva. Joseph Berger, Bugwood.org chewing mouthparts and can clip off • Pheromone traps can be used to seedlings at the soil line reducing stands. monitor adult male moths. Later in the season, fruit and foliage may be damaged. Threat Level: Cutworms infestations are sporadic. Damaging Lifestage(s): Larva Top Management Techniques: Life Cycle: • Remove cool-season weeds along • Egg | Larva | Pupa | Adult field edges (e.g. lambsquarters and • 2 overlapping generations of black wild mustards). Cutworm eggs and newly hatched larvae. Charles Olsen, USDA Frank Peairs, Colorado State University, and variegated cutworms per year. • Fall tillage can help destroy or expose Variegated cutworm larva. APHIS PPQ, Bugwood.org • 1 generation of army, pale western, overwintering pupae. Bugwood.org and glassy cutworms per year. • Focus on fields with an early season • Overwinter as larvae in the soil or weed infestation, and those planted under plant debris. late. • Protect seedlings with cardboard Time for Concern: Cutworms are most collars. active and cause the most damage during spring and early summer months. When to Consider Treatment: If chronic cutworm infestations have been experienced, or large numbers of overwintering cutworms are observed. Cutworm moths have varied wing patterns and Cutworm larvae feed at the soil surface and can cut off wingspans. John Capinera, University of Florida, Bugwood.org the stems of young plants. Clemson University - USDA Cooperative Look-alikes: armyworms, corn earworm Extension Slide Series, Bugwood.org 36 37 INSECT PESTS INSECT PESTS

DIAMONDBACK MOTH Plutella xylostella A: 12-15 mm wingspan L: 1.7-11.2 mm long

Hosts: brassicas including broccoli, When and Where to Scout: Brussels sprouts, cabbage, cauliflower, • Monitor for adults with pheromone Chinese cabbage, collards, kale, kohlrabi, traps starting in mid-spring. mustard, radish, rutabaga, turnip, • Larvae can be found feeding on the watercress, and many related weeds undersides of leaves.

CATERPILLARS • Eggs are found on the undersides of Diamond back moth adult. David Cappaert, Bugwood.org Diamond back moth egg. Whitney Cranshaw Colorado State /MOTHS Appearance: Adults are slender, grayish leaves or lower stalks. University Bugwood.org brown moths with distinct diamond- • Scout for larvae, pupae, and feeding shape markings on the back and are most injury on leaves of susceptible plants

active at night. Eggs are small, relatively at the seedling stage, during crop /MOTHS

flat, yellowish-white and laid singly or in thinning, and just before crop head CATERPILLARS groups. Larvae are pale yellow-green and formation. have a habit of wriggling vigorously or dropping from a plant on a string of silk Threat Level: Diamondback moth is when disturbed. the primary caterpillar pest in commercial brassica crops, and rarer in home gardens. Damage Symptoms: Larvae feed with Feeding damage and contamination (larval chewing mouthparts causing “window body or frass) are of most concern in

panes” and/or ragged holes in leaves and brassicas. Damage is variable from year-to- Diamond back moth larva. Cami Cannon, Utah State University Diamond back moth pupa and "window pane" feeding sometimes serious defoliation. Larval year but can be serious. damage. Cami Cannon, Utah State University bodies and frass contaminate harvested brassicas. Top Management Techniques: • Heavy irrigation can reduce early Damaging Lifestage(s): Larva larval populations. • Use row covers on susceptible crops. Life Cycle: • Hand pick and destroy larvae. • Egg | Larva | Pupa | Adult • Application of insecticides; Bt and • 4-6 overlapping generations per year. spinosad are effective. • Overwinter as adults in warmer, southern locations. When to Consider Treatment: When 5% of susceptible crops are infested Time for Concern: Early May through with larvae and before they move into crop harvest. Strong winds from southern heads or broccoli and cauliflower buds. Diamond back moth damage on cabbage; note the Diamondback moth larva, feeding damage, and locations may suddenly increase ragged holes and smaller cabbage head (right). Diane Alston, excrement. Gerald Holmes, California Polytechnic State University at San Luis populations while cold, wet weather may Look-alikes: cabbage looper (larva, Utah State University Obispo, Bugwood.org reduce populations. Damage typically pupa), imported cabbageworm (larva) occurs after head formation begins in brassicas, but caterpillars sometimes attack seedling plants.

38 39 INSECT PESTS INSECT PESTS

IMPORTED CABBAGEWORM (CABBAGE WHITE BUTTERFLY) Pieris rapae A: 45-65 mm wingspan L: 3.2-30 mm long

Hosts: brassicas including broccoli, When and Where to Scout: Brussels sprouts, cabbage, and many • Watch for white butterflies during the related weeds day. • Beginning at the button stage (before CATERPILLARS Appearance: Adults are white-yellow cauliflower and broccoli heads begin /MOTHS butterflies, active during the day and to elongate and expand) examine 10 Imported Cabbageworm adult. Cami Cannon, Utah State University Imported Cabbageworm eggs are rocket-shaped and often seen fluttering above crops during leaves from 10 different plants at 10 yellow in color. Bonnie Bunn, Utah State University the summer. Eggs are small, yellow, different locations of the field. rocket-shaped, and usually found on • Look for small larvae and eggs on /MOTHS brassica leaves. Larvae are green, sluggish the undersides of leaves and larger CATERPILLARS caterpillars with a fuzzy body due to short caterpillars toward the center of the hairs. plant or near the midribs of leaves. • Feeding damage and frass Damage Symptoms: Larvae feed with (excrement) are also signs of an chewing mouthparts causing “window infestation. panes” and/or ragged holes in leaves and sometimes serious defoliation. Larval Threat Level: Imported cabbageworm is bodies and frass contaminate harvested a common pest of home gardens. Feeding brassicas. damage and contamination (larval body or frass) are of most concern in brassicas. Damaging Lifestage(s): Larva

Top Management Techniques: Imported Cabbageworm larva. Utah State University Imported Cabbageworm pupa. Whitney Cranshaw Colorado State Life Cycle: • Use row covers. University Bugwood.org • Egg | Larva | Pupa | Adult • Remove plant debris at the end of the • 3-4 generations per season. growing season. • Overwinter as pupae on leaves and • Hand-pick and destroy larvae. occasionally on debris. • Application of insecticides; Bt and spinosad are effective. Time for Concern: Early June through September. When to Consider Treatment: If 2 or more medium-sized larvae are found per 10 leaves at the button stage, two sprays will be needed: 1) a spray at button stage and 2) a clean-up spray 7-10 days before harvest. Organic options are available. Imported Cabbageworm damage. Whitney Cranshaw, Colorado Imported Cabbageworm adult and damage on cabbage. State University, Bugwood.org Ward Upham, Kansas State University, Bugwood.org Look-alikes: diamondback moth (larva), cabbage looper (larva)

40 41 INSECT PESTS INSECT PESTS

TOMATO & TOBACCO HORNWORM Tomato Hornworm (Manduca quinquemaculata) Tobacco Hornworm (Maduca sexta) A: 100-120 mm wingspan

L: 6.7-81.3 mm long

Hosts: tomato, pepper, potato, and others When and Where to Scout:

CATERPILLARS Newly hatched tomato hornworm larva. Cami Cannon, Utah such as some nightshade family weeds and • Larval populations peak in mid- State University /MOTHS tobacco summer. Tomato hornworm adult. Utah State University • Start monitoring in early July. Appearance: Adults are large moths also • Larvae are easiest to see when actively known as sphinx, hawk, or hummingbird feeding near dusk and dawn. /MOTHS CATERPILLARS moths. Larvae are large, cylindrical and • Visually monitor plants for feeding usually green in color. Tomato hornworm damage, defoliation, larvae, dark larvae have eight white “v” shaped marks droppings, or fruits with large, deep, along each side and a black horn at the end cavities. of its body. The tobacco hornworm has seven diagonal white stripes along its body Threat Level: Hornworm populations and a horn at the end of its body that is often do not cause economic injury due to Tomato hornworm feeding damage on tomato plant; usually orange or red. predation from natural enemies. However, note dark excrement next to the plant. Utah State University localized plant defoliation in backyard Damage Symptoms: Larvae use gardens or in high tunnels can occur. chewing mouthparts to feed primarily on leaves, but will also eat blossoms, stems, Top Management Techniques: and fruits, leaving behind dark green or • Plow field after harvest to destroy black frass. Larvae can defoliate plants and pupae. scar fruit, especially when populations are • Rotate crops. high. • Larvae can be handpicked. Tomato hornworm larva feeding on a partially • Spot treat infected plants; Bt and defoliated tomato plant. Utah State University Damaging Lifestage(s): Larva spinosad are effective.

Life Cycle: When to Consider Treatment: Tomato hornworm larva and feeding damage on tomato • Egg | Larva | Pupa | Adult If larvae are causing extensive defoliation, fruit. Utah State University • 1-2 generations per year. or if they are feeding on fruit. • Overwinter as pupae in the soil. Look-alikes: whitelined sphinx larvae Time for Concern: July until the end of (which rarely causes significant damage) the season. Tobacco hornworm larvae. Eddie McGriff, University of Georgia, Bugwood.org

Tobacco hornworm feeding damage. John C. French Sr., Retired, Universities:Auburn, GA, Clemson and U of MO, Bugwood.org 42 43 INSECT PESTS INSECT PESTS

EUROPEAN EARWIG Forficula auricularia A: 13-14 mm long N: 4.2-11 mm long

Hosts: Wide host range including beans, When and Where to Scout: beets, cabbage, cauliflower, celery, chard, • Place boards, corrugated cardboard, corn, cucumber, lettuce, pea, potato, rolled-up or crumpled moistened European earwig adult. Males have strongly curved European earwig adult. Females forceps at the tip of the rhubarb, tomato, flower petals, as well as newspaper, or bait containers (e.g. forceps (tip of abdomen). David Cappaert, Bugwood.org abdomen are only slightly curved . David Cappaert, Bugwood.org other insects and organic matter tuna can, yogurt container) with smelly oils (e.g. clam oil, bacon Appearance: Adults are slender with grease) in crop areas early spring and a brown body, red-brown head, and a monitor weekly. prominent pair of “pinchers” (cerci) on • Adults like to hide in dark, tight, and the rear of the body. European earwigs moist places during the daytime and are omnivores, feeding on a diverse diet may seek shelter inside buildings. including plants, fungal spores, small • Eggs are laid in clusters of 30-40 EARWIGS invertebrates, and decaying organic matter. within nests in the soil.

Damage Symptoms: Earwigs feed on Threat Level: It is more abundant in Earwig adults like to hide in dark, tight, and moist Earwig feeding damage on cabbage. Bonnie Bunn, Utah State EARWIGS buds, flowers, fruits, corn silks (and some highly irrigated or mulched areas. places during the daytime. Bonnie Bunn, Utah State University University corn kernels), tender vegetable seedlings, and leaves causing direct plant damage, Top Management Techniques: reduced crop yields, and aesthetic injury. • Only manage when there is They like to crawl into tight, dark places to unacceptable crop damage. spend the day making them an unwanted • Use traps to monitor and reduce presence in harvested fruits, vegetables and numbers. flowers. • Reduce or remove nesting and hiding places. Damaging Lifestage(s): Nymph, Adult When to Consider Treatment: Life Cycle: Since European earwigs can be both

• Egg | Nymph (4 stages) | Adult beneficial and detrimental to crops, European earwig adult male. Whitney Cranshaw, Colorado State European earwig feeding damage on common mallow. • 2 or more generations per year. only consider treatment when there is University, Bugwood.org Whitney Cranshaw, Colorado State University, Bugwood.org • Overwinter as brooding pairs or unacceptable crop damage. above ground in aggregations. Look-alikes: none Time for Concern: Populations tend to build to their highest densities in mid- to late summer.

European earwigs in Allium flower at night.Whitney European earwig pitfall trap with canola oil. Whitney Cranshaw, Colorado State University, Bugwood.org Cranshaw, Colorado State University, Bugwood.org 44 45 INSECT PESTS INSECT PESTS

GRASSHOPPERS Differential Grasshopper...... A: 44.5 mm long (Melanoplus differentialis) Migratory Grasshopper...... A: 25.4 mm long (Melanoplus sanguinipes) Redlegged Grasshopper...... A: 25.4-38.1 mm long (Melanoplus femurrubrum) Twostriped Grasshopper...... A: 31.8-50.8 mm long (Melanoplus bivittatus)

Differential grasshopper adult. David Cappaert, Bugwood.org Migratory grasshopper adult. Joseph Berger, Bugwood.org Hosts: Almost all vegetable plants • Number of grasshoppers present in late summer and early fall can be Appearance: Adults and nymphs have a good indicator of problems the a robust body, hind legs with enlarged subsequent year. femurs for long-distance jumping, and relatively short antennae. Threat Level: Utah’s grasshopper populations fluctuate from year to year. Damage Symptoms: Adults and Large populations can be economically nymphs feed with chewing mouthparts damaging but outbreaks are hard to causing random, ragged holes in leaves, predict. Redlegged grasshopper adult. Russ Ottens, University of Georgia, Twostriped grasshopper adult. Whitney Cranshaw Colorado State

GRASSHOPPERS flowers, and sometimes immature pods Bugwood.org University Bugwood.org and fruit. Top Management Techniques: • Manage nymphs with bait before the Damaging Lifestage(s): Nymph, Adult majority of the population is more than ½ grown. Life Cycle: • Encourage area-wide control.

• Egg | Nymph (5 stages) | Adult • Protect crops with floating row GRASSHOPPERS • Most species in Utah have 1 covers. generation per year. • Till soil in and near plantings to • Overwinter as eggs within pods in the discourage egg-laying. soil. • Application of baits, dusts, and sprays may be needed. Grasshopper eggs. John Gavloski Entomologist, Manitoba Grasshopper nymph. Cami Cannon, Utah State University Time for Concern: Damage occurs starting in early summer after rangeland When to Consider Treatment: weeds dry up and may continue all season. During periods when a local outbreak develops, control usually involves using When and Where to Scout: sprays or baits. Apply in spring and early • Eggs hatch from late May to early summer when nymphs are young and July. concentrate at sites where egg laying • Look for nymphs from late May to occurs. Area wide (multiple-farm) control early July to determine when eggs is most effective. have hatched. • Watch for ragged holes in plants. Look-alikes: none

Grasshopper feeding damage. Cami Cannon, Utah State University Grasshopper feeding damage. Cami Cannon, Utah State University

46 47 INSECT PESTS INSECT PESTS

BEET LEAFHOPPER Circulifer tenellus A: 3 mm long

Hosts: beans, beets, borage, cucumber, Time for Concern: Early summer when flax, gourds, melon, pepper, potato, weeds begin to dry up and for the first 6-8 pumpkin, spinach, Swiss chard, weeks of planting. tomato, and weeds such as filaree, kochia, lambsquarters, mustard family When and Where to Scout: weeds, pepperweed, pigweed, plantain, • Adults move into cultivated areas Beet leafhoppers are wedge-shaped with a slightly roof- Beet leafhoppers have a face absent of clearly defined rabbitbrush, Russian thistle, sagebrush, when weeds begin to dry up. shaped face (as opposed to well-rounded or sharply spots. University of Wyoming Extension pointed). University of Wyoming Extension shepherd's purse, and verbena • Adults and nymphs are difficult to differentiate from other leafhopper Appearance: Adults and nymphs jump species. when disturbed and have wedge-shaped • Symptoms of curly top virus may bodies varying in color from pale green, occur in susceptible hosts before gray, or tan. Adults are winged, but not nymphs or adults are seen. nymphs. Threat Level: Direct feeding damage Damage Symptoms: Adults and is not economically important, but beet nymphs feed with piercing sucking leafhoppers can infect plants with curly top mouthparts which can cause shriveled and virus for which there is no cure; remove Beet leafhopper adult. G. Oldfield, USDA, Bugwood.org Beet leafhopper adult. University of Idaho Extension burned leaves under severe infestations. infected plants to slow virus spread. The beet leafhopper can transmit curly top virus to beans, beets, cucurbits, Top Management Techniques: flax, pepper, potato, spinach, squash, • Exclude leafhoppers with floating Swiss chard, and tomato. Curly top virus row covers. symptoms include small twisted leaves • Shade tomato and pepper plants. LEAFHOPPERS with purple veins, thickened crisp leaves, • Destroy and remove plant debris. yellowing and death of mature leaves, • ‘Hide’ susceptible plants among small fruits that ripen prematurely, reduced resistant plants. fruit quality and yield, and stunted growth. (see Curly top virus on pg. 140-141). When to Consider Treatment: Insecticide applications directed at Tomato plant infected with curly top virus. Cami Cannon, LEAFHOPPERS Utah State University Damaging Lifestage(s): Nymph, Adult leafhoppers are ineffective.

Life Cycle: Look-alikes: other leafhopper species • Egg | Nymph | Adult (e.g. potato leafhopper) • Multiple generations per growing season. • Overwinter as adults on weeds and volunteer plants in southern Utah. • Adults migrate north on spring wind currents. Beet leafhopper adult, nymphs, and damage to host Curled, yellowed, and crispy tomato leaves infected with plants. Art Cushman, USDA Systematics Entomology Lab, Bugwood.org curly top virus. Cami Cannon, Utah State University

48 49 INSECT PESTS INSECT PESTS

POTATO LEAFHOPPER Empoasca spp. A: 3 mm long

Hosts: Wide host range including alfalfa, When and Where to Scout: beans, eggplant, potato, and weeds • Look for pale leaf veins and curling including pigweed and shepherd’s purse leaves on host plants starting in spring. Appearance: Adults are wedge-shaped, • Look under leaves of host plants for light green in color, and widest at the green flying or jumping insects or head with an elongated body. Both adults for the pale, flightless nymph which

and nymphs move quickly and can run readily moves when disturbed. Potato leafhopper nymph. Frank Peairs, Colorado State University, Potato leafhopper adult. Steve L. Brown, University of Georgia, forward, backward, or sideways. Bugwood.org Bugwood.org Threat Level: This pest rarely causes Damage Symptoms: Adults and significant damage to vegetables in Utah. nymphs feed with piercing-sucking Potato leafhoppers are known to vector mouthparts that result in white flecked the fire blight bacterium which is a serious injury and sometimes premature disease of pear, apple, and related pome plant death (potato). “Hopperburn” fruit trees. characterized by yellowing and necrosis of leaflets and eventually defoliation, is rarely Top Management Techniques: seen in Utah. • Spray high pressure water to dislodge nymphs. Damaging Lifestage(s): Nymph, Adult • Use floating row cover.

Life Cycle: When to Consider Treatment: Potato leafhopper adult and nymph. Penn State College of • Egg | Nymph (5 stages) | Adult Generally, potato leafhopper does not Agricultural Sciences • Several overlapping generations per cause enough damage in Utah vegetables LEAFHOPPERS year. to require treatment. • Overwinter in warmer locations (not Northern Utah). Look-alikes: other leafhopper species (e.g. beet leafhopper), spider mite (damage) Time for Concern: Early June through August. LEAFHOPPERS

Potato leafhopper adult, nymph, and "hopper burn" (rare in Utah) damage. Art Cushman, USDA Systematics Entomology Laboratory, Bugwood.org

Potato leafhopper adult, nymphs, and "hopper burn" (rare in Utah) damage to potato foliage. Mary Foley Benson, USDA; Property of the Smithsonian Institution, Department of Entomology, Bugwood. org

50 51 INSECT PESTS INSECT PESTS

CARROT RUST FLY Psila rosae A: 6 mm long L: 3-8 mm long

Hosts: Primarily carrot but sometimes When and Where to Scout: celeriac, celery, coriander, dill, fennel, • Monitor adults with yellow sticky parsley, parsnip, and turnip cards beginning in late April and throughout the season. Appearance: Adults are small, black, slender flies with a reddish yellow head Threat Level: This pest is sporadic and yellowish legs. Larvae are creamy in Utah, and when present, can be Carrot rust fly adult. Rasbak, wikimedia commons Carrot rust fly adult.Remi Coutin 1997 white maggots with a tapered body. Larvae economically damaging. tunnel through the lower third of carrot roots with rasping mouth hooks and may Top Management Techniques: kill plants. • Row covers. • Harvest carrots in blocks (rather than Damage Symptoms: Feeding damage selectively) as soon as possible. occurs as mined roots, particularly the • Remove all carrots from the ground lower third. Young plants may be killed after harvest. while older carrots sustain scarring, with burrows often a red rusty color. Damage When to Consider Treatment: can promote rotting. When there are 2-3 adults per sticky trap per field. Damaging Lifestage(s): Larva Look-alikes: seedcorn maggot, onion Life Cycle: maggot, cabbage maggot, leafminers • Egg | Larva | Pupa | Adult Look-alikes: onion maggot (adult), Carrot rust fly damage. Rasbak wikimedia Carrot rust fly damage. Remi Coutin 1997 Carrot rust fly damage. Whitney Cranshaw, • 2-3 generations per year. commons Colorado State University, Bugwood.org • Overwinter as pupae in the soil or seedcorn maggot (adult), cabbage maggot occasionally as larvae in roots. (adult), leafminers (adult), other root and seed maggots (adult) Time for Concern: May until harvest. MAGGOTS /FLIES /FLIES MAGGOTS

Carrot rust fly larva. Rasbak wikimedia commons Carrot rust fly pupae. Remi Coutin 1997

52 53 INSECT PESTS INSECT PESTS

LEAFMINERS American Serpentine Leafminer...... A: 1-1.7 mm long ...... L: 0.4-3 mm long (Lyriomyza trifolii) Pea Leafminer...... A: 1.3-2.3 mm long ...... L: 0.4-3.25 mm long (Lyriomyza langei) Spinach Leafminer...... A: 5-6 mm long ...... L: 6-8 mm long (Pegomya hyoscyami) American serpentine Pea leafminer adult. Jeffery Spinach leafminer adult. Vegetable leafminer adult. Vegetable Leafminer...... A: 1.3-1.5 mm long ...... L: 0.6-3 mm long adult. Central Science Laboratory Lotz and Gary Steck FDACS-DPI Whitney Cranshaw, Colorado State Pest and Diseases Image Library (Lyriomyza sativae) Harpenden British Crown Bugwood. University, Bugwood.org Bugwood.org org

Hosts: Wide host range including beans, When and Where to Scout: beets, carrot, celery, cucumber, eggplant, • Starting in May, begin looking for lettuce, melon, onion, pea, pepper, potato, small rows of white, oblong eggs on spinach, squash, Swiss chard, tomato, and host leaves. weeds such as lambsquarter and related • Fully grown, larvae drop to the weeds ground, and pupate in the soil.

Appearance: Adults flies range in color Threat Level: In general, more than 5% from black to gray; some bear yellow infestation of potential harvest of leafy markings. Eggs are oblong and white in greens. Leafminer eggs. Cami Cannon, Utah State University Leafminer larvae are usually hidden inside a leaf but can be exposed by tearing off the top or bottom layer of color. the leaf. Cami Cannon, Utah State University Top Management Techniques: Damage Symptoms: Larvae feed and • Exclude adult flies with row cover. tunnel between the upper and lower leaf • Crop rotation. surfaces causing irregular shaped, whitish • Cultivate soil after harvest to disturb mines or “blisters”. Mines are initially pupae. opaque, eventually turning brown. Pale yellow larvae may be found within the When to Consider Treatment: mines. If populations are high and causing economic damage. Damaging Lifestage(s): Larva Look-alikes: onion maggot (adult), Leafminer damage to chard. Cami Cannon, Utah State University Leafminer damage to onion. Cami Cannon, Utah State University Life Cycle: seedcorn maggot (adult), cabbage maggot MAGGOTS (adult), carrot rust fly (adult), other root

/FLIES • Egg | Larva | Pupa | Adult • Several generations per season. and seed maggots (adult) • Pupae overwinter in the soil, emerging mid-spring. /FLIES MAGGOTS

Time for Concern: Early in the season.

Leafminer damage to a small, early-season pea plant. Extensive leafminer damage to chard . Cami Cannon, Utah State Cami Cannon, Utah State University University

54 55 INSECT PESTS INSECT PESTS

CABBAGE MAGGOT Delia radicum A: 5-7 mm long L: 6-7.6 mm long

Hosts: beets, broccoli, Brussels sprouts, When and Where to Scout: cabbage, cauliflower, celery, collards, cress, • Adults emerge in early May. kohlrabi, radish, turnip, and other brassicas • Larvae burrow into the stem of host plants or feed on roots or stems. Appearance: Onion maggots and • As susceptible crops emerge, watch cabbage maggots look very similar and are for wilting, reduced growth, and signs most easily distinguished by the crops they of chlorosis (yellowing). Cabbage maggot adult. James Lindsey, creative commons Cabbage maggot larva and pupa. Rasbak attack. Adult flies are slightly smaller and • If maggots are suspected, pull up more slender than houseflies with longer affected plants and check roots and legs and overlapped wings at rest. Eggs are soil to confirm maggot presence. If oblong and white in color. tunnels are found in roots, but no maggots are present, then maggots Damage Symptoms: Larvae feed on have already exited roots to pupate in roots of crops and can tunnel through the soil. taproots providing entry for decay, fungi, and bacteria. Damaged plants show Threat Level: This pest is sporadic and wilting, reduced growth, and lighter green can be very serious, but cultural methods plant parts. are generally adequate for control.

Damaging Lifestage(s): Larva Top Management Techniques: • Rotate susceptible crops with Life Cycle: unrelated crops. Cabbage maggot eggs, larva, pupa, and adults. Cornell Cabbage maggot eggs on host. Ken Gray Insect Image University • Egg | Larva | Pupa | Adult • Plant seeds into raised soil beds to • 2 generations per year. promote soil drying and warming. • Overwinter as pupae in the soil and • Destroy or disc under crop residues crop debris. immediately after harvest.

Time for Concern: April through When to Consider Treatment: July under cool and moist conditions. In most cases, adequate control is possible MAGGOTS with cultural control and practices /FLIES Populations tend to decline in summer heat but can be high if soils are cooler that speed up germination and plant than normal due to a particularly rainy emergence. season. Small, slow-growing, young plants /FLIES MAGGOTS are most susceptible to the first generation. Look-alikes: onion maggot, seedcorn maggot, carrot rust fly, leafminers (adult), other root and seed maggots (adult) Cabbage maggot damage to broccoli. OMAFRA Cabbage maggot damage on a young cabbage plant; note the chlorotic (yellowing) plant parts. Mary Ann Hansen, Virginia Polytechnic , Institute and State University, bugwood.org

56 57 INSECT PESTS INSECT PESTS

ONION MAGGOT Delia antiqua A: 5-7 mm long L: 6-10 mm long

Hosts: onion, garlic, leek, carrot, radish, When and Where to Scout: and related allium crops including wild • Monitor adults with yellow sticky relatives of onion cards starting in mid-May. • First generation adults emerge in Appearance: Onion maggots and approximately mid-May with peak cabbage maggots look very similar and are flights about 2 weeks later.

most easily distinguished by the crops they • Larvae burrow into the basal plate of Onion maggot adult. Ken Gray Insect Image Collection Onion maggot eggs near host plant. Ken Gray Insect Image attack. Adults flies are slightly smaller and the onion plant or feed on the roots. Collection more slender than houseflies with longer • Watch for wilting, death, or reduced legs and overlapped wings at rest. Eggs are quality in onion plants. oblong and white in color. Threat Level: Damage is uncommon in Damage Symptoms: Larvae use hooked Utah due to soils low in organic matter mouthparts to feed on roots and bulbs and typically dry, warm conditions in the of young plants, causing wilting and plant spring. death. Feeding can also result in rotting bulb tissue and provide openings for Top Management Techniques: other diseases, reducing bulb quality and • Rotate onions with unrelated crops. storability. • Avoid herbicide, cultivation, and disease damage to onion plants. Damaging Lifestage(s): Larva • Remove and destroy volunteer onions

in the spring and onion culls and Onion maggot larvae. Wikimedia commons Onion maggot pupae. Pest and Diseases Image Library Bugwood.org Life Cycle: debris from fields after harvest, and • Egg | Larva | Pupa | Adult till in the fall. • 3 generations per season. • Overwinter as pupae in the soil When to Consider Treatment: among harvested onions and culls. In most cases, adequate control is possible with cultural control and practices Time for Concern: that speed up germination and plant MAGGOTS May through the end

/FLIES of the season. emergence.

Look-alikes: cutworm (damage), /FLIES

cabbage maggot, seedcorn maggot, carrot MAGGOTS rust fly, leafminers (adult), other root and seed maggots (adult)

Onion maggot levels of injury. Onion maggot damage to onion bulb. Wikimedia commons

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SEEDCORN MAGGOT Delia platura A: 4.8-6.4 mm long L: 5-6.3 mm long

Hosts: cabbage, corn, bean, melon, cress, When and Where to Scout: beet, celery, broccoli, cauliflower, collards, • Adult flies emerge in April and May. kohlrabi, Brussels sprouts, radish, turnip, • Larvae burrow into seeds and feed on and other warm-season plants emerging cotyledons. Seedcorn maggot adult. Pest and Diseases Image Library, Bugwood.org Seedcorn maggot larvae may feed on underground • Watch for reduced plant stands which stems. Whitney Cranshaw, Colorado State University, Bugwood.org Appearance: Adults flies slender and may indicate maggot feeding. grayish black in color. Eggs are oblong and • Monitor with yellow sticky cards. white in color. Threat Level: Damage is uncommon in Damage Symptoms: Larvae burrow Utah due to soils low in organic matter into seeds and roots of many vegetable and typically dry, warm conditions in the crops, destroy the seed germ, and may spring. cause rot in plant tissue. Seeds and plants attacked may not emerge causing reduced Top Management Techniques: stands. Larvae are sometimes secondary • Rotate susceptible crops with pests on plants that have been damaged by unrelated crops. disease. • Plant seeds into raised soil beds to promote soil drying and warming. Damaging Lifestage(s): Larva • Destroy or disc under crop residues Seedcorn maggot damage. Mariusz Sobieski, Bugwood.org Seedcorn maggot on a corn seed. Mariusz Sobieski Bugwood.org immediately after harvest. Life Cycle: • Egg | Larva | Pupa | Adult When to Consider Treatment: • 2-3 generations per year. In most cases, adequate control is possible • Overwinter as pupae in the soil. with cultural control and practices that speed up germination and plant Time for Concern: At planting. emergence.

Look-alikes: cabbage maggot, onion maggot, bean seed maggot, carrot rust MAGGOTS

/FLIES fly, leafminers (adult), other root and seed maggots (adult) /FLIES

Cabbage infested with seedcorn maggot (left); note the MAGGOTS yellow leaves and stunted growth. Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org

Seedcorn maggot life stages and damage. Art Cushman, USDA Systematics Entomology Laboratory, Bugwood.org

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OTHER ROOT MAGGOTS Bean Seed Maggot...... A: 6.35 mm long ...... L: 6.35 mm long (Delia florigela) Radish Root Maggot...... A: 5-6 mm long ...... L: 7.9 mm long (Delia planipalpis) Sugarbeet Root Maggot...... A: 6.35 mm long...... L: 8.4 mm long (Tetanops myopaeformis)

Hosts: Bean seed maggot: similar hosts When and Where to Scout: to seedcorn maggot (pg. 60-61). Radish • Watch for larval tunneling in the

root maggot: roots of crucifers including, roots of host plants throughout the Radish root maggot adult. University of Alberta E.H. Strickland Sugarbeet root maggot adults. Whitney Cranshaw, Colorado State radish, turnip, cabbage, Chinese cabbage, season. Entomological Museum University, Bugwood.org and mustard family weeds. Sugarbeet root • Check host plant roots for decay. maggot: sugarbeet, beet, spinach • Watch plants for wilting.

Appearance: Adults are gray flies Threat Level: Damage is uncommon in resembling small house flies. Larvae are Utah due to soils low in organic matter pale maggots associated with roots of host and typically dry, warm conditions in the plants. spring.

Damage Symptoms: Larvae feed Top Management Techniques: on and tunnel through roots of host • Plant seeds into raised soil beds to plants causing decay, openings for other promote soil drying and warming. organisms, and sometimes wilting of the • Destroy or disc under crop residues entire plant. immediately after harvest. Sugarbeet root maggot adult. Ken Gray Insect Image Collection Damaging Lifestage(s): Larva When to Consider Treatment: In most cases, adequate control is possible Life Cycle: with cultural control and practices • Egg | Larva | Pupa | Adult that speed up germination and plant • 2-3 generations per year. emergence. • Overwinter as pupae in the soil. Radish root maggot damage to radish. Melodie Putnam, Oregon Look-alikes: cabbage maggot, onion State University MAGGOTS

/FLIES Time for Concern: At planting. maggot, seedcorn maggot, carrot rust fly, leafminers (adult), other root and seed maggots (adult) /FLIES MAGGOTS

Sugarbeet root maggot damage to roots. Ken Gray Insect Image Collection

Sugarbeet root maggot larva. Ken Gray Insect Image Collection

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FALSE CHINCH BUG Nysius raphanus N, A: 2-4 mm long

Hosts: Wide variety including brassicas, When and Where to Scout: lettuce, mustard greens, potato, quinoa, • Adults and nymphs move to radish, turfgrass and weeds such as kochia, developing mustards in early spring. mustard family weeds, pigweed, Russian • Look for aggregations on individual thistle, and sagebrush plants during July and early August. • Adults and nymphs are most active Appearance: Adults are brownish gray during cooler mornings or late

with silvery wings. Nymphs are mottled evenings. False chinch bug adult. Russ Ottens, University of Georgia, Bugwood. False chinch bug adult. Marion Murray, Utah State University gray brown with red to orange markings org on the abdomen. Threat Level: False chinch bug feeding does not seem to be very destructive to Damage Symptoms: Adults and vegetables and often little, if any injury is nymphs feed with piercing-sucking observed. Spot infestations are sporadic mouthparts. Large numbers of aggregating but can cause wilting and plant death, adults on individual plants can cause plants especially early in the year. to wilt and die rapidly. Outbreaks that destroy plantings usually occur early in the Top Management Techniques: year. Later in the season aggregations are • Low numbers do not need to be False chinch bug nymph. HortNET The False chinch bug nymph. HortNET The False chinch bug egg. HortNET The commonly seen on developing seed heads. managed. Horticulture and Food Research Institute of New Horticulture and Food Research Institute of New Horticulture and Food Research Institute of New • Row covers on crops near Zealand Bugwood.org Zealand Bugwood.org Zealand Bugwood.org Damaging Lifestage(s): Nymph, Adult uncultivated areas of mustard family plants. Life Cycle: • Keep plants well irrigated. • Egg | Nymph (4 stages) | Adult • About 3 generations per year. When to Consider Treatment: • Overwinter as nymphs and adults If economically damaging infestations are under debris near winter annual present. mustards. Look-alikes: beneficial big-eyed bug, Time for Concern: July and early August. chinch bug, other seed bugs

False chinch bug damage. Whitney Cranshaw Colorado State False chinch bug (left) and the beneficial big-eyed bug University Bugwood.org (right). Ronald Smith, Auburn University, Bugwood.org PLANT/SEED BUGS BUGS PLANT/SEED

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LYGUS BUG (TARNISHED PLANT BUG) Tarnished plant bug (Lygus lineolaris)...... A: 3.7-6 mm long Western tarnished plant bug (Lygus hesperus)...... A: 4.2-5.2 mm long

Hosts: Wide host range including When and Where to Scout: asparagus, cabbage, carrot, celery, lettuce, • Visually scout or use sweep nets and lima bean, snap bean, soybean, tomato, regularly examine flowers to monitor several other vegetables, seed crops, alfalfa, for adults and nymphs starting in fruit, and weeds such as butterweed, dock, early spring. dog fennel, fleabane, goldenrod, and vetch • Watch for feeding damage throughout the season. Western tarnished lygus adult. Whitney Cranshaw Colorado State Tarnished lygus adult. Russ Ottens University of Georgia Bugwood.org Appearance: Adults are brown with University Bugwood.org yellow, black, and red markings and have Threat Level: Commonly found in a yellow or green triangle on the upper Utah and can cause economic injury to center of the back. Nymphs are usually vegetables. Low densities can be tolerated lighter in color with dark spotting and a when plants are vegetative. more rounded form. Top Management Techniques: Damage Symptoms: Adults and • Remove preferred hosts (flowering nymphs feed with piercing-sucking weeds, legumes, alfalfa) from field mouthparts, causing shriveled seeds, edges. premature drop of buds, flowers, and • Control weeds. fruits, ragged discolored leaves, bronzing, • Application of insecticides may be and cat-facing (on fruit). needed. Tarnished lygus egg. Scott Stewart University of Tennessee Bugwood.org Tarnished lygus multiple life stages. University of Georgia University of Georgia Bugwood.org Damaging Lifestage(s): Nymph, Adult When to Consider Treatment: If feeding damage is high. Thresholds vary Life Cycle: depending on the crop. • Egg | Nymph | Adult • 3-4 generations per year. Look-alikes: other plant bugs, beneficial • Overwinter as adults in plant debris. big-eyed bug

Time for Concern: Throughout the season.

Lygus bug damage to bean pods and seeds. Howard F. Tarnished plant bug damage on daisy. Whitney Cranshaw, Schwartz, Colorado State University, Bugwood.org Colorado State University, Bugwood.org PLANT/SEED BUGS BUGS PLANT/SEED

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RED FIRE BUG Pyrrhocoris apterus N, A: 6.5-12 mm long

Hosts: Plants the mallow family, such as When and Where to Scout: linden, common mallow, okra and cotton; • Adults become active in April. some other plants, such as tomato • Adults and nymphs avoid direct sunlight and can be found in masses Appearance: Adults are vibrant red with in grass, leaf litter, trees, plant foliage, varying wing markings (most commonly and shaded soil beneath plants. two black dots on shortened wings). Young nymphs look similar to boxelder bugs Threat Level: Red fire bug is a nuisance Red fire bug adult.Bonnie Bunn, Utah State University Red fire bug nymph.Bonnie Bunn, Utah State University while older nymphs begin to resemble pest; no significant plant damage has been adults. Adults and nymphs feed on seeds reported to date. with piercing-sucking mouthparts. The red fire bug can be a nuisance pest when it Top Management Techniques: forms aggregations. • Directly spray congregations with water to drown them. Damage Symptoms: Adults and • Spray with insecticidal soap. nymphs can be found massing on • Application of insecticides may be structures, plants, and under leaf litter, needed; pyrethroids are effective. but no significant plant damage has been reported to date. When to Consider Treatment: There are no insecticides specifically Damaging Lifestage(s): Nymph, Adult registered for red fire bug in Utah, but

insecticides effective on other plant/seed Red fire bug adults can be a nuisance when they form Red fire bug adult.Cami Cannon, Utah State University Life Cycle: bugs will be effective on red fire bug. The aggregations. • Egg | Nymph (5 stages) | Adult insect does not have to occur on the label, • 1 generation per year. but the plant site must be there. • Overwinter as adults. Look-alikes: boxelder bugs Time for Concern: April through fall. PLANT/SEED BUGS Red fire bug adults move quickly when disturbed.Cami Red fire bug adult.Bonnie Bunn, Utah State University Cannon, Utah State University BUGS PLANT/SEED

68 69 INSECT PESTS INSECT PESTS

SQUASH BUG Bactericera cockerelli N, A: 2.5-17 mm long

Hosts: winter squash, summer squash, • Look daily for eggs under leaves and melon starting in late spring and early summer until harvest. Appearance: Adults are flat and brown • Watch for plant wilt. to gray with orange and brown bands • Adults and nymphs congregate on along the margins of the abdomen. Eggs lower parts of the plant. are shiny bronze to red and located on undersides of leaves. Nymphs are bright Threat Level: Squash bugs are common green but become gray-brown and begin to in cucurbits (especially pumpkin and resemble adults as they mature. squash) occurring every year and can be very difficult to control when populations Squash bug adult. Cami Cannon, Utah State University Squash bug egg cluster. Cami Cannon, Utah State University Damage Symptoms: Adults and are allowed to build. nymphs feed with piercing-sucking mouthparts initially causing small yellow Top Management Techniques: flecks on foliage that eventually turn • Rotate crops annually to a non- brown. Later, foliage often wilts and dies cucurbit crop. beyond damaged areas. Feeding may occur • Remove or till under plant debris at on fruit causing scars and wounds that the end of the season and keep fields are readily colonized by rotting organisms free of trash or wood. resulting in increased fruit rot in the field • Place wooden boards between and during storage. susceptible plants and lift them each morning to destroy aggregated adults Damaging Lifestage(s): Nymph, Adult and existing eggs. • Avoid heavy mulch or no-till in Life Cycle: susceptible varieties. Squash bug early nymph. Bonnie Bunn, Utah State University Squash bug late nymphs. Cami Cannon, Utah State University • Egg | Nymph (5 stages) | Adult • When scouting, remove egg masses. • 1 generation per year (potentially a • Cover young squash plants with partial second generation in southern row cover to exclude squash bugs; Utah). uncover in the morning hours when • Overwinter as adults in protected plants are in bloom. sites around building and under plant • Application of insecticides may be debris or compost piles. needed.

Time for Concern: When plants develop When to Consider Treatment: runners through harvest. If 1 egg mass per plant is found in the

PLANT/SEED early flowering stage. Insecticides work best on nymphs. Squash bugs are BUGS When and Where to Scout: Note: • Monitor in the spring for squash bug prone to developing resistance and adults are difficult to kill.

adults under plant debris, perennial BUGS plants, or near buildings. Squash bug feeding can cause host leaves to dieback, Squash bug aggregation and damage on pumpkin. Whitney PLANT/SEED Look-alikes: brown marmorated stink turning yellow and then brown. Utah State University Cranshaw, Colorado State University, Bugwood.org bug, stink bugs, boxelder bugs (nymphs), other leaffooted bugs 70 71 INSECT PESTS INSECT PESTS

Threat Level: Small numbers of stink • Attract and conserve natural enemies. STINK BUGS bugs can cause serious damage to fruits • Application of insecticides are often Brown marmorated stink bug (BMSB) (Halyomorpha halys)...... A: 12-17 mm long and vegetables. Stink bugs can be difficult necessary. Brown stink bug (Euschistus servus)...... A: 11-15 mm long to kill with insecticides due to their Conchuela stink bug (Chlorochroa ligata)...... A: 13-19 mm long strong flight capability and tolerance to When to Consider Treatment: Consperse stink bug (Euschistus conspersus)...... A: 8-12 mm long insecticide residues. Brown, consperse, and • For consperse and green stink bugs, Green stink bug (Acrosternum hilare)...... A: 13-19 mm long onespotted stink bugs are only minor pests when stink bug counts average one in Onespotted stink bug (Euschistus variolarius)...... A: 11-15 mm long of fruits and buds. BMSB is a new invasive three shake samples. Time treatments Say’s stink bug (Chlorochroa sayi)...... A: 8-19 mm long pest in Utah; it has the potential to cause in tomatoes to start when fruits reach Uhler stink bug (Chlorochroa uhleri)...... A: 12-16 mm long severe crop damage. 1 inch in diameter. • For BMSB, action thresholds have Top Management Techniques: not yet been developed. Hosts: Wide host range including stink bugs (Brochymena quadripustulata, B. • Plant trap crop barriers around asparagus, corn, eggplant, green bean, pustula) is mostly a predator of insects but border of cash crop. Look-alikes: squash bug, beneficial stink okra, pepper, Swiss chard, tomato, and sometimes feeds on leaves. • Row covers or fine-mesh netting over bugs listed above, western conifer-seed others including fruit trees, and ornamental plants in gardens and small acreage bug, leaffooted bug plants Damaging Lifestage(s): Nymph, Adult crops.

Life Cycle: Appearance: Adults are shield-shaped BMSB adults are distinguished by smooth and rounded shoulders, white bands on antennae bugs. Eggs are barrel-shaped and laid in • Egg | Nymph (5 stages) | Adult and legs, and alternating dark and light bands on margins of the abdomen. clusters of 10-30 on host leaves. See pages • 2-3 overlapping generations per year. 73-75 for specific species descriptions. • Overwinter as adults under leaves, plant debris, weedy areas, and other Damage Symptoms: Nymphs protected sites such as buildings or and adults feed with piercing-sucking structures, wood piles, or dead trees. mouthparts primarily causing damage to fruiting parts of plants. Damage initially Time for Concern: From July through occurs as hard, whitish, callous areas harvest (damage may be greater during surrounding a central feeding puncture, warm, dry periods). later developing into cloudy areas of hard yellow spots. Fruit begins to grow in a When and Where to Scout: distorted manner, with indented areas • Infestations typically occur along field developing at the feeding sites (catfacing). edges. Young fruit may abort from stink bug • Look for eggs on host plants along damage and seeds of legumes may be field edges starting in late spring and BMSB adult and feeding damage on a corn leaf; note BMSB egg shells and newly hatched nymphs. Gary Bernon, white bands on legs and antennae. Cami Cannon, Utah State USDA APHIS, Bugwood.org killed or shrunken after pod feeding. throughout the season. University Green fruit damage occurs as dark • Shake foliage over a beating sheet/ pinpricks surrounded by a light colored tray and count fallen nymphs and area. Damage may cause poorly developed adults. flavor of fruits and vegetables. • Monitor for BMSB with Pherocon® PLANT/SEED BMSB and GSB lures on a

BUGS Beneficial Stink Bugs: Most stink bugs Pherocon® STKY™ dual panel clear feed on plants, but a few are beneficial sticky trap.

predators including the twospotted stink • Watch for feeding injury on fruit and BUGS

bug (Perillus bioculatus) and spined soldier vegetables. PLANT/SEED bug (Podisus maculiventris). The rough BMSB nymph. Cami Cannon, Utah State University BMSB nymph. Susan Ellis, Bugwood.org

72 73 INSECT PESTS INSECT PESTS

Conchuela stink bug dark green to black body with orange or red margins on the sides and STINK BUGS (CONT.) an orange or red spot near the tip of the abdomen. Brown marmorated stink bug (BMSB) (Halyomorpha halys)...... A: 12-17 mm long Brown stink bug (Euschistus servus)...... A: 11-15 mm long Conchuela stink bug (Chlorochroa ligata)...... A: 13-19 mm long Consperse stink bug (Euschistus conspersus)...... A: 8-12 mm long Green stink bug (Acrosternum hilare)...... A: 13-19 mm long Onespotted stink bug (Euschistus variolarius)...... A: 11-15 mm long Say’s stink bug (Chlorochroa sayi)...... A: 8-19 mm long Uhler stink bug (Chlorochroa uhleri)...... A: 12-16 mm long

Brown stink bug adults are brown and look similar to BMSB but have more pointed shoulders, and yellowish, less apparent bands on its antennae.

Conchuela stink bug adult; red Conchuela stink bug eggs. Conchuela stink bug nymph. Salvador phase. Whitney Cranshaw, Colorado State Whitney Cranshaw, Colorado State University, Vitanza, Ph.D. University, Bugwood.org Bugwood.org

Consperse stink bug adults are gray-brown with black specks and yellow to green on the underside.

Brown stink bug adult; note pointed shoulders and lack Brown stink bug eggs. Herb Pilcher, USDA Agricultural Research Service, of banding on antennae. Stopbmsb.org Bugwood.org

Consperse stink bug adult; note darker tips of antennae. Stopbmsb.org PLANT/SEED BUGS

Brown stink bug newly hatched nymphs. Herb Pilcher, USDA Brown stink bug late nymph. Russ Ottens, University of Georgia, BUGS Agricultural Research Service, Bugwood.org Bugwood.org PLANT/SEED

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Say’s stink bug similar to conchuela stink bug with a green body with orange or white STINK BUGS (CONT.) margins on the sides and orange markings on the head and body. Brown marmorated stink bug (BMSB) (Halyomorpha halys)...... A: 12-17 mm long Brown stink bug (Euschistus servus)...... A: 11-15 mm long Conchuela stink bug (Chlorochroa ligata)...... A: 13-19 mm long Consperse stink bug (Euschistus conspersus)...... A: 8-12 mm long Green stink bug (Acrosternum hilare)...... A: 13-19 mm long Onespotted stink bug (Euschistus variolarius)...... A: 11-15 mm long Say’s stink bug (Chlorochroa sayi)...... A: 8-19 mm long Uhler stink bug (Chlorochroa uhleri)...... A: 12-16 mm long

Green stink bug adults are bright green and yellow on the underside near the head and legs.

Say's stink bug adult. William M. Ciesla, Forest Health Management International, Bugwood.org

Uhler stink bug similar in appearance to the Say’s and conchuela stink bugs but with yellow to white markings instead of orange or red.

Green stink bug adult. Susan Ellis, Bugwood.org Green stink bug egg shells and newly hatched nymphs. Susan Ellis, Bugwood.org

Onespotted stink bug is brown and looks similar to the brown stink bug but with more sharply pointed shoulders with orange tips. PLANT/SEED BUGS

Uhler stink bug adult. Ken Schneider BUGS PLANT/SEED

Onespotted stink bug adult; note sharply pointed shoulders. Stopbmsb.org 76 77 PSYLLIDS

79 INSECT PESTS INSECT Whitney Whitney Cami Cannon, Utah State Yellow potato foliage due to psyllid yellows. foliage potato yellows. due to psyllid Yellow Bugwood.org State University, Colorado Cranshaw, Psyllid damagePsyllid on potato foliage leaves. curled can cause Eugene E. Nelson, Bugwood.org Microscopic view of a psyllid nymph. University Cami Cannon, Utah State University Marion Murray, Utah State University Marion Murray, Whitney Cranshaw, Colorado State University, Bugwood.org State University, Colorado Cranshaw, Whitney Psyllid nymphs and adults. Psyllid nymphs and adults. Psyllid yellows can cause yellow or reddish-pink can cause yellow Psyllid yellows discoloration of potato foliage. Adult psyllid.

A: 2 mm long A: 2 mm Psyllid yellows is generally Psyllid yellows winged aphids (adults)

and eggs. Monitoring is a critical component of management decisions. Application of are insecticides; there non-chemical currently no effective controls for potato psyllid. Place yellow sticky cards as soon as sticky Place yellow startsthe potato season to detect the first occurrence of psyllid in the area. and eggsLook for nymphs on the undersides of 10 collecting by leaves from the middle ofmature leaves the among the outer plant at 10 locations ofrows field. the to see nymphs A hand lens is needed • • • • • Look-alikes: Look-alikes: Threat Level: Threat disease. less damaging than zebra chip for potato can be destructive Zebra chip tomato, production), (especially for chip and pepper and is occasionally seen in these crops in Utah. Management Techniques: Top to Consider Treatment: When If caused zebra chip potato psyllids have in past years, disease or psyllid yellows if fields are experiencing these nearby or ifproblems, is detected, potato psyllid ifeven populations are low. When and Where to Scout: Where and When

Nymph, Adult

Nymphs As soon as potato

Adults resemble small Adults resemble

Many solanaceous plants including Many solanaceous Candidatus Liberibacter solanacearum Egg | Nymph (5 stages) | Adult Multiple generations per season. as adults in warmerOverwinter locations (not northern Utah).

• • • 78 Time for Concern: season starts until the end of the season. Life Cycle: Damaging Lifestage(s): tomato, and pepper. (see Zebra chip on pg. on pg. (see Zebra chip and pepper. tomato, 108-109). poor quality fruits. Potato psyllids also Potato poor quality fruits. vector disease in potato, causes zebra chip which potatoes results in reduced size, premature potatoes results in reduced size, damage sprouting, and rough skin. Tomato includes the production of small, soft, yellows”. Common symptoms of Common symptoms yellows”. psyllid are leafyellows plant slowed curling, Damage to growth, color changes. and and adults feed with piercing-sucking and adults feed with piercing-sucking mouthparts causing disruptions in plant described as “psyllid growth, collectively body with spines around the edges. Damage Symptoms: ‘V’ on the back. Nymphs are flat, Nymphs ‘V’ on the back. green green(yellowish or orange when newly and an oval-shaped with red eyes, hatched), cicadas or winged aphids, readily jump cicadas or winged aphids, bodies black have when disturbed, and and a white inverted with white markings nightshades, and bindweed and bindweed nightshades, Appearance: Hosts: eggplant, tomato, certain pepper, potato, Bactericera cockerelli Bactericera POTATO/TOMATO PSYLLID POTATO/TOMATO INSECT PESTS INSECT PSYLLIDS INSECT PESTS INSECT PESTS

THRIPS Onion Thrips (Thrips tabaci) A: 1.3 mm long Western Flower Thrips (Frankliniella occidentalis) A: 1.5 mm long

Hosts: Wide host range including Threat Level: Thrips populations THRIPS artichoke, beans, cabbage, cauliflower, increase under hot, arid conditions leading corn, cucurbits, eggplant, garlic, leafy to economic crop losses on certain onions.

greens, leek, lettuce, onion, pea, pepper, Serious infestations in cabbage make the THRIPS tomato, and many grasses, flowers, and crop unmarketable. Tomato spotted wilt many weeds virus may be vectored by thrips and can cause death in some host plants. Iris yellow Thrips adult on onion. Cami Cannon, Utah State University Thrips adult, feeding damage, and excrement (black Appearance: Adults are minute with spot virus vectored by onion thrips and specks) on early season cucurbit. Cami Cannon, Utah State elongated yellow or yellow-brown bodies can cause reduced bulb size and quality in University and two pairs of fringed (hairy) wings. allium crops. Larvae are creamy yellow. Top Management Techniques: Damage Symptoms: Thrips feed with • Plow under plant debris after harvest a punch-and-suck behavior causing light and remove volunteer host plants. flecking wounds and silvery scars, often • Inspect transplants for thrips with dark fecal spots. Thrips may vector infestations (using a 10x hand lens) tospoviruses including tomato spotted wilt and discard infested plants. virus (tomato, pepper, tobacco) and iris • Use overhead sprinkler irrigation to yellow spot virus (allium crops). wash thrips from plants. • Remove weeds near vegetable fields. Damaging Lifestage(s): Instars (larval • Application of insecticides may be stages) I and II, and Adult needed. Thrips adult and nymphs in the Silvering damage caused by thrips When to Consider Treatment: Thrips feeding damage on foliage Life Cycle: neck of onion. can leave specks of yellow/chlorotic feeding on onion. • Egg | Larvae (4 stages) | Pupa| • Thrips have rapidly developed tissue. Cami Cannon, Utah State University Adult resistance to several classes of • 5-8 generations per year. insecticides. Insecticides will be most • Overwinter as adults in plant debris effective when used in conjunction and protected areas. with other non-pesticide management practices. Time for Concern: Populations are • For onions: favored by hot, arid conditions and –– June to early July in highly decrease with heavy rain or overhead susceptible onion varieties (e.g. irrigation. red onions): 115 thrips per plant. –– July and August in more tolerant When and Where to Scout: onion varieties (many yellow and • Adults become active in the spring. white varieties): 30 thrips per • Onion thrips are commonly found in plant. the neck of the onion. • Look for silvery scars, bleached spots Look-alikes: beneficial thrips (e.g. black Microscopic view of onion thrips. Alton N. Sparks, Jr., University of Microscopic view of western flower thrips. Jack T. Reed, on foliage, and dark fecal spots. hunter thrips, banded thrips or Aeolothrips) Georgia, Bugwood.org Mississippi State University, Bugwood.org

80 81 INSECT PESTS INSECT PESTS

WHITEFLIES Family: Aleyrodidae A: 1.5-2.5 mm long

Hosts: Wide host range of vegetables When and Where to Scout: and ornamentals including ageratum, • Look for large colonies during warm aster, beans, begonia, calendula, cucumber, weather on the underside of lower grape, hibiscus, lantana, nicotiana, leaves. poinsettia, squash, tomato • Inspect transplants for whiteflies. • Monitor with yellow sticky cards to WHITEFLIES Appearance: Adults are tiny with white detect whitefly presence. wings that are held roof-like over their Whitefly adults.Central Science Laboratory, Harpenden , British Crown, Whitefly eggs.David Riley, University of Georgia, Bugwood.org body. Immature stages are inconspicuous Threat Level: Economic damage from Bugwood.org with pale, almost translucent, flat bodies whiteflies in the garden or field is rare

that resemble scale nymphs. in Utah and is more commonly seen in WHITEFLIES greenhouses or high tunnels. Damage Symptoms: Adults and nymphs feed with piercing-sucking Top Management Techniques: mouthparts, causing leaves to turn yellow, • Attract and conserve natural enemies. appear dry, or fall off plants. Whiteflies, • Inspect transplants and remove any like aphids, also excrete a sugary substance with high whitefly populations. called honeydew, causing sticky leaves or • Remove infested leaves or hose them sooty mold growth on leaves. down with water sprays.

Damaging Lifestage(s): Nymph, Adult When to Consider Treatment: Whiteflies develop resistance to Life Cycle: insecticides quickly and treatment is not • Egg | Nymph (3 feeding stages 1 generally needed for garden plants in Utah. Whitefly nymph. Florida Division of Plant Industry, Florida Department of Whitefly adult and nymphs.Clemson University - USDA Cooperative nonfeeding stage) | Pupa | Adult Greenhouse plants have a threshold of 10 Agriculture and Consumer Services, Bugwood.org Extension Slide Series, Bugwood.org • Several generations per year. nymphs/leaf. • Populations continue from year to year in greenhouses and in the far Look-alikes: aphid skins, leafhopper south. adults, scale insects

Time for Concern: During warm weather, on transplants, or when natural enemies are disrupted by insecticide applications, dusty conditions, or interference with ants that are attracted to the honeydew secreted by whiteflies.

Whitefly adults on squash.Marion Murray, Utah State University Whitefly infestation. Gerald Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.org

82 83 INSECT PESTS INSECT PESTS

BANK'S GRASS MITE Oligonychus pratensis A: 0.8 mm long

Hosts: corn and other grasses including When and Where to Scout: turfgrass • Adults are active from late spring throughout the summer. Appearance: Very small arachnids • Cream-colored, spherical eggs are laid (requiring a 10x lens) with yellowish to in clusters on stems and leaves. greenish bodies and patchy black spots that • Watch for stippling on leaves and cover the sides of the abdomen. Colonies webbing.

are often associated with webbing. Bank's grass mite adult. F.C. Schweissing, Bugwood.org Bank's grass mites and eggs (clear and round). Frank Peairs, Threat Level: Occasional damage occurs Colorado State University, Bugwood.org Damage Symptoms: Mites feed with on sweet corn when mites feed on leaves piercing-sucking mouthparts causing and scar husks. stippling (tiny yellow or brown spots),

MITES silver discoloration, and sometimes a burnt Top Management Techniques: appearance on the upper leaf surface. • Reduce drought stress.

Severe damage from mite feeding causes • Manage grassy weed hosts. MITES leaves to desiccate and drop, stalks to • Avoid broad-spectrum pesticides that break, and corn kernels to shrink. suppress beneficial mite predators. • Application of pesticides may be Damaging Lifestage(s): Nymph, Adult needed.

Life Cycle: When to Consider Treatment: • Egg | Larva | Nymph (2 stages) | Pesticides are typically necessary when 15- Adult 20% of the leaf area is covered with mite • Multiple, overlapping generations per colonies, leaf damage is noted, and hot, year. dry conditions are predicted. Bank's grass mites. Whitney Cranshaw, Colorado State University, Bank's grass mite damage to sweet corn husk. Whitney Bugwood.org Cranshaw, Colorado State University, Bugwood.org • Overwinter as adults in the soil, leaf litter, and weeds. Look-alikes: two-spotted spider mite

Time for Concern: Corn is most susceptible to yield damage from the tasseling stage to the soft dough stage of growth.

Bank's grass mite damage to sweet corn. Whitney Cranshaw, Bank's grass mite damage to corn. Frank Peairs, Colorado State Colorado State University, Bugwood.org University, Bugwood.org

84 85 INSECT PESTS INSECT PESTS

BULB MITES Rhyzoglyphus spp. A: 0.4 mm long Tyrophagus spp.

Hosts: Wide host range (many kinds of When and Where to Scout: bulbs, roots, and tubers) including onion, • Adults and nymphs are typically garlic, lily, dahlia, tulip, hyacinth, freesia, found in clusters under the root plate and gladiolus of onion bulbs or garlic cloves. • Watch for feeding damage symptoms Appearance: Bulb mites are shiny, which resemble those of damping-

creamy white, bulbous mites often off caused by Pythium. Tyrophagus mite magnified about 100x.Eric Erbe, USDA Tyrophagus mite magnified.Charley Eiseman described as pearls with legs. Agricultural Research Service, Bugwood.org Threat Level: Bulb mites primarily feed Damage Symptoms: Adults and on decaying fungi but can greatly aggravate nymphs feed with piercing-sucking existing plant wounds and promote decay

MITES mouthparts on the roots, basal plate, in plants. Growing tips of bulbs can be and outer layer of plant tissue providing damaged and cause distortion under high

openings for soil-borne fungal pathogens numbers of bulb mites. This pest can also MITES such as Pythium, Rhizoctonia, and continue to develop on bulbs in storage. Fusarium. Bulb mites can reduce plant stands and vigor, and promote rot of bulbs Top Management Techniques: in storage. • Rotate crops. • Allow crop residues to fully Damaging Lifestage(s): Nymph, Adult decompose prior to planting. • Use clean seed and transplants. Tyrophagus mite magnified.Don Loarie Life Cycle: • Clean bulbs before storage and store • Egg | Larva | Nymph (2 stages) | in cool temperatures with low relative Adult humidity. • Multiple, overlapping generations per • Application of pesticides may be Tyrophagus mite magnified.Don Loarie year. needed. • Overwinter on decaying vegetation D such as weeds or crop debris. When to Consider Treatment: No thresholds have been established. A F Time for Concern: Injury typically occurs during early vegetative growth Look-alikes: insect eggs, root aphids stages and is most damaging when plant E growth is slowed by cool, wet weather. G Infestations can affect bulbs both in field B and in storage. A-adult female; B-egg; C-larva; D-protonymph; E-hypopus; C F-tritonymph; G-section of damaged bulb

Bulb mite stages of development and feeding injury. UMass Amherst

86 87 INSECT PESTS INSECT PESTS

TOMATO RUSSET MITE Aculops lycopersici A: 0.15-0.2 mm long

Hosts: tomato, eggplant, pepper, potato, When and Where to Scout: tomatillo, and weeds of other solanaceous • The presence of tomato russet mites plants, nightshade weeds, and morning often goes unnoticed, due to their glory tiny size, until injury is evident. • Watch for injury symptoms especially Appearance: Adults and nymphs have during hot, dry conditions. cigar-shaped, yellowish-tan or pink bodies • Look for bronzing on lower leaves and require a microscope to observe. and stems. Microscopic view of tomato russet mites on tomato Microscopic view of tomato russet mites on tomato • Use a microscope to check damaged stem; note the cigar-shape of the mites. Cami Cannon, Utah stem. Cami Cannon, Utah State University Damage Symptoms: Adults and leaves and surrounding healthy leaves State University nymphs feed with piercing-sucking for mites. mouthparts causing bronzing or

MITES “russeting” of the surface of stems, leaves, Threat Level: If not controlled, this and fruits. Damaged leaves may turn pest can kill plants. Tomatoes are most

yellow, curl, wither, appear “deflated”, and commonly affected, especially during hot, MITES fall from plants. Mite feeding on fruits dry conditions. can cause longitudinal cracks and bronze coloration. Top Management Techniques: • Avoid planting during hot, dry Damaging Lifestage(s): Nymph, Adult periods. • Promptly remove or destroy infested Life Cycle: plant debris. • Egg | Nymph | Adult • Clean tools used on infested plants • Multiple, overlapping generations per before using on healthy plants. year. • Applications of pesticides. Tomato russet mites and damage on tomato. NSW Tomato russet mite damage on tomato. Cami Cannon, Utah • Overwinter as adults in crop debris. Department of Primary Industries State University When to Consider Treatment: Time for Concern: When weather Once russet mites are present on plants, conditions are hot and dry. insecticide treatment (sulfur, abamectin) is the primary control option.

Look-alikes: nutritional deficiencies (damage), plant diseases (damage), water stress (damage)

Tomato russet mite damage on tomato; note the Tomato russet mite damage on tomato. Utah State University "deflated" appearance of the dying stem.Cami Cannon, Utah State University

88 89 INSECT PESTS INSECT PESTS

TWOSPOTTED SPIDER MITE Tetranychus urtica A: 0.4-0.6 mm long

Hosts: beans, beets, carrot, corn, When and Where to Scout: cucurbits (cucumber, squash, melon), • Check the undersides of leaves for eggplant, parsley, pea, pepper, potato, moving specks of “dirt” (twospotted sweet potato, tomato, and many weeds and spider mites can look like dirt without other plants a hand lens). • Start with older leaves and leaves Appearance: Tiny mite (best seen with closest to the ground. a 10x hand lens or microscope) with a • Watch for injury symptoms especially Twospotted spider mite adult. Twospotted spider mite adults and egg. yellowish body and two dark spots on during hot, dry conditions. either side of its back. • Webbing indicates the presence of heavy populations. Damage Symptoms: Feeds with

MITES piercing-sucking mouthparts resulting in Threat Level: If not controlled, this pest stippling at feeding sites. A generalized can kill plants.

bronzing or reddish discoloration often MITES develops as infestations progress. Plant Top Management Techniques: vigor may be seriously reduced, and • Keep plants healthy and free of premature leaf drop often occurs on drought stress. heavily infested plants. Webbing may be • Avoid broad-spectrum pesticides that visible when populations on plants are suppress beneficial mite predators. high. When to Consider Treatment: Damaging Lifestage(s): Nymph, Adult Twospotted spider mites show high resistance to pesticides. No thresholds have Life Cycle: been established but consider treatment Twospotted spider mite infestation on bean. Cami Cannon, Twospotted spider mite feeding damage causes leaves to Utah State University die. Cami Cannon, Utah State University • Egg | Larva | Nymph (2 stages) | when mites are easily detectable, damage is Adult. evident, and hot, dry conditions persist. • 8 or more generations per year. • Overwinter as adults in ground cover Look-alikes: leafhopper (damage), around the base of host plants. drought stress (damage), beneficial predatory mite Galendromus, Bank’s grass Time for Concern: Anytime weather mite conditions are hot and dry.

Twospotted spider mite feeding damage on tomato fruit, Twospotted spider mite feeding damage on tomato leaf. stem, and foliage. Cami Cannon, Utah State University Cami Cannon, Utah State University

90 91 INSECT PESTS INSECT PESTS

SYMPHYLANS (GARDEN CENTIPEDE) Garden symphylan (Scutigerella immaculata) A: 2-10 mm long

Hosts: Wide range of vegetables • Soil, bait, and indirect sampling are especially cabbage, carrot, beet, broccoli, the three main sampling methods lettuce, potato, radish, spinach, and squash, used to identify damage and inform and several small fruits, flowers, and plants management decisions. More with flower bulbs information on these methods can

be found online in the ATTRA Garden symphylan. Soniamartinez Garden symphylan. Ken Gray Insect Image Collection Appearance: Adults are slender, publication “Symphylans: Soil Pest elongated, “centipede-like”, and white with Management Options”. prominent antennae. They have 15 body segments, 10-12 pairs of legs, and move Threat Level: Symphylans are limited to rapidly when disturbed. All life stages areas with clay soils, particularly those high occur in the soil, typically in the upper in organic matter. In more tolerant crops, few inches. Symphylans feed on sprouting such as potato, bean, and small grains, seeds and underground plant parts. feeding may not lead to significant damage, even at considerably high population Damage Symptoms: Feeding damage densities. Moderately to highly susceptible

SYMPHYLANS causes root death on younger roots and crops include broccoli, squash, spinach, a gnarled appearance with corky tissues and cabbage. Commonly damaged crops forming around wound sites on older include broccoli and other cole crops, roots. Damage also includes reduced spinach, beets, onions, and squash. stands, general stunting, and susceptibility

to soil-borne plant pathogens. Top Management Techniques: Garden symphylan damage can cause reduced stands. Garden symphylan damage can cause gnarled roots with SYMPHYLANS • Tillage. UC ANR a corky appearance. Ken Gray Insect Image Collection Damaging Lifestage(s): Nymph, Adult • Plant potatoes to decrease symphylan population levels. Life Cycle: • Use transplants instead of direct • Egg | Nymph (7 molts) | Adult seed or increase transplant size (not • 1-2 generations per year. effective for broccoli and eggplant). • Overwinter as adults in the soil. When to Consider Treatment: Time for Concern: Throughout the Noticeable damage often occurs if garden season, especially in (heavy) clay soils high symphylans exceed an average of 5-10 in organic matter. per shovelful in moderately to highly susceptible crops such as broccoli, squash, When and Where to Scout: spinach, and cabbage. In conventional • Garden symphylans are not always cropping systems, 2-3 garden symphylans easy to find due to their patchy per square foot is commonly used as a distribution. They tend to occur in treatment threshold. “hotspots” of a few square feet to several acres. Look-alikes: springtails/collembola

92 93 INSECT PESTS INSECT PESTS

SPRINGTAILS (COLLEMBOLA) Class: Collembola A: 1.5-3.2 mm long Common families: Sminthuridae, Entomobyryidae, Onychiuridae

Hosts: Multiple vegetables especially When and Where to Scout: spinach and beets • Commonly found in heavy, organic soils during wet, cool spring Appearance: Adults are small, six- conditions. legged arthropods with elongate or • Watch for reduced stands and loss of bulbous bodies that are dully colored plant vigor.

purplish gray, cream, or brown. Many Globular springtail adult. Joseph Berger, Bugwood.org Springtail adult. Susan Ellis, Bugwood.org springtails have a unique tail-like structure Threat Level: Springtails rarely cause (furcula) that hooks under the body and economic injury. is used, by snapping downward, to jump short distances when disturbed or during Top Management Techniques: mating. • Reduce moisture and excess organic matter. Damage Symptoms: Some species feed with piercing-sucking mouthparts When to Consider Treatment: while others feed with complex, highly No thresholds have been developed, but specialized mouthparts. Feeding damage control measures are rarely needed. on roots and germinating seeds of small plants causes loss of plant vigor and Look-alikes: fleas (jumping), symphylans reduced stands. /COLLEMBOLA

SPRINGTAILS Damaging Lifestage(s): Adult

Life Cycle: Springtail adults. Joseph Berger, Bugwood.org Springtail adult. Joseph Berger, Bugwood.org • Egg | Adult • Variable generations per year. SPRINGTAILS

• Overwinter primarily as resting adults /COLLEMBOLA below the soil surface.

Time for Concern: May and June.

Springtails and feeding damage. University of Minnesota Springtail feeding damage. University of Minnesota

94 95 INSECT PESTS INSECT PESTS

PILLBUGS AND SOWBUGS Family: Armadillidiidae A: 6.3-12.7 mm long

Hosts: beans, lettuce, melon, mustard, When and Where to Scout: pea, radish, tomato, and other vegetable • Adults and young hide under plant crops debris when temperatures are warm. • Adults and young thrive in areas of Appearance: Adults have a rounded high moisture. back with a flat under-surface and are • Adults and young are most active dark gray in color with armor-like body at night when humidity is high and

segments. Pillbugs and sowbugs are not temperatures are low. Pillbug adult. Joseph Berger, Bugwood.org Pillbug adult. Joseph Berger, Bugwood.org insects, but are soil-dwelling crustaceans with 7 pairs of legs and prominent Threat Level: Pillbugs and sowbugs antennae. are usually minor pests but occasionally become numerous enough to damage Damage Symptoms: Pillbug and roots, seedlings, foliage, and fruits and sowbug feeding damage looks similar to vegetables that contact the soil. They slug damage, ragged holes chewed between primarily feed on decaying organic matter leaf veins. These crustaceans thrive where and are opportunistic feeders following soil is moist and rich in organic matter. disease, slug, and other pest damage.

Damaging Lifestage(s): Young, Adult Top Management Techniques: • Minimize soil moisture. Life Cycle: • Remove debris such as trash, plant • Egg | Young | Adult debris, wood, or other items on the • 1-2 generations per year. soil. • Overwinter as adults. • Trellis vines to improve air circulation. Pillbug adult. Joseph Berger, Bugwood.org Pillbug adult and young. Lyle J. Buss, University of Florida Time for Concern: When fruits or • Use plastic mulches as a barrier to vegetables have direct contact with damp soil contact for developing fruits. soil.

CRUSTACEANS When to Consider Treatment: Generally cultural management practices are most effective in preventing pillbugs and sowbugs from becoming a problem.

Look-alikes: none CRUSTACEANS

Sowbug adult. James Castner, University of Florida Pillbugs feeding on a young garden plant. D.W. Reed

96 97 INSECT PESTS INSECT PESTS

SLUGS AND SNAILS A: 25-38 mm long

Hosts: Wide variety, especially beans, When and Where to Scout: corn, and lettuce plus many non-vegetable • Slugs and snails are first seen in the plants spring. • They are active at night or on dark, Appearance: Adults are soft-bodied cloudy days. mollusks that leave behind a mucus or • They avoid sunny, dry conditions. slime as they travel. As the mucus dries, it • During the day, they migrate to forms a shiny white, silvery trail, indicating sheltered areas under debris and in Snail on pea plant. Cami Cannon, Utah State University Snail feeding on cabbage. UC IPM Project, University of California that the pests are present. Eggs are small, soil cracks. round, pearl-like and white, covered in a layer of mucus, and laid in groups of Threat Level: This pest is sporadic but about 25-120. wet weather and poorly composted organic matter favor population increase. Activity Damage Symptoms: Slugs and snails is low during hot, dry weather. chew irregular holes that have smooth edges in leaves, eat flowers, clip off small Top Management Techniques: plants and plant parts, and are particularly • Remove boards, stones, and any damaging to new seedlings and maturing debris that shelters slugs and snails. vegetables or fruits that touch the soil. • Lure and destroy slugs and snails with They typically leave slime trails on areas bait, lumber, or produce scrap traps. where they have been active. • Handpick and destroy snails and slugs when practical. Damaging Lifestage(s): Juvenile, Adult • Use drip or other water-conserving irrigation methods to reduce the Slug juvenile and eggs. Watchduck (a.k.a. Tilman Piesk) Slug damage to tobacco. R.J. Reynolds Tobacco Company, Life Cycle: extent of soil wetness. Bugwood.org • Egg | Juvenile | Adult • Increase sun penetration to dry • 1-2 generations per year. vegetation and soil. • Overwinter as eggs, juveniles, or • Application of bait stations and adults. chemical baits.

Time for Concern: Throughout the When to Consider Treatment: season. When infestations are severe.

Look-alikes: wind or hail damage (damage) MOLLUSCS MOLLUSCS Slug damage. Iowa State University Slug damage to hosta leaves. Missouri Botanical Garden

98 99 DISEASES DISEASES

DISEASES, ABIOTIC DISORDERS, AND NEMATODES

Bacterial Diseases...... 98 Fungal Diseases...... 106 Fungal-Like Diseases...... 126 Nematode-Caused Diseases...... 132 Viral Diseases...... 134 Abiotic (Non-Living)...... 150 DISEASES DISEASES BACTERIAL DISEASES BACTERIAL CANKER Caused by: Clavibacter michiganensis subsp. michiganensis Spread by: infected transplants/seed; bacteria in splashing water; or on field equipment and tools DISEASES BACTERIAL

Hosts: tomato (primarily) and pepper When and Where to Scout: • Examine lower leaves starting in Symptoms: Infections can be systemic late spring for wilting and marginal (wilting due to vascular infection) or necrosis (death of the outer edge). superficial (surface of leaves, stems, and • Both green and ripe fruit can be fruit). Systemic infections cause foliar infected. wilting and marginal necrosis, starting with • If plants are wilting, select a few Bacterial canker and wilt of tomato symptoms on Bacterial canker causes vascular discoloration in stems. the lower leaves. In superficial infections, plants and cut the stems lengthwise tomato. Heinz USA , Bugwood.org Utah State University lesions on leaves are small, circular, white and inspect the pith for necrosis. to brown spots while on fruit, they are raised, dark brown spots with a white halo. Threat Level: Sporadic and rare in Utah, but can be devastating where present. Disease Cycle: • Introduction to new fields occurs Top Management Techniques: through infected seedlings or seeds. • Start with disease-free seed and Bacteria spread locally in splashing transplants. water or on field equipment and • Rotate with non-host crops. tools. • Avoid overhead irrigation. • Bacteria survive up to three years in plant debris, and for several months When to Consider Treatment: on stakes and equipment. Use copper at time of diagnosis, repeated at 7-day intervals as needed. Time for Concern: Any time temperatures are warm (75 to 90°F) and Look-alikes: Verticillium wilt (leaf Bacterial canker causes white spots with dark centers on Bacterial canker and wilt of tomato symptoms on fruits. Utah State University tomato fruit. Heinz USA , Bugwood.org moist. necrosis is instead v-shaped) and early blight (leaf lesions instead have concentric rings)

Bacterial Canker wilt of tomato symptoms. Mary Ann Hansen, Cross-section through a diseased tomato stem. Gerald Virginia Polytechnic Institute and State University, Bugwood.org Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.org

102 103 DISEASES DISEASES BACTERIAL DISEASES BACTERIAL SPECK Caused by: Pseudomonas syringae pv. tomato Spread by: infected transplants/seed; bacteria in splashing water; or on field equipment and tools DISEASES BACTERIAL

Hosts: tomato When and Where to Scout: • Start examining undersides of Symptoms: Symptoms on leaves are leaves soon after planting, especially concentrated near margins and are most following cool, wet weather. prominent on the undersides, consisting of • Continue through early summer. brown to black spots with a yellow halo. Spots on fruit are scabby, pinpoint-like, Threat Level: Minor. Bacterial speck symptoms on tomato leaf. Gerald Holmes, Bacterial speck symptoms on tomato leaf. Gerald Holmes, and range in color from brown to black. California Polytechnic State University at San Luis Obispo, Bugwood.org California Polytechnic State University at San Luis Obispo, Bugwood.org Damage does not penetrate into the flesh. Top Management Techniques: • Delay planting until cool, wet Disease Cycle: conditions are over. • Introduction to new fields occurs • Avoid overhead irrigation. through infected seedlings or seeds. • Rotate with a non-host crop such as Bacteria spreads locally in splashing small grains or corn. water or on field equipment and tools. When to Consider Treatment: • Bacteria survive up to three years in Copper before a cool, rain event, repeated plant debris, and for several months at 14-day intervals as needed. on plant stakes and equipment. Look-alikes: early blight (leaf lesions Time for Concern: Infections may occur instead have concentric rings), bacterial during cool (63 to 75°F) wet conditions. canker (spots on fruit have a white halo)

Bacterial speck symptoms on tomato leaf. Marion Murray, Bacterial speck symptoms on tomato leaf. Utah State University Utah State University

Bacterial speck on fruit. Utah State University Bacterial speck on fruit. Marion Murray, Utah State University

104 105 DISEASES DISEASES BACTERIAL DISEASES BACTERIAL STALK ROT Caused by: Several formae speciales (special forms) of Erwinia carotovora New Name: Pectobacterium carotovorum Spread by:

surface water from overhead/flood irrigation; rain-splash from previously-infected DISEASES crop debris BACTERIAL

Hosts: Primarily corn (forma speciales When and Where to Scout: zeae). Other P. carotovorum strains cause a • Examine corn after extended periods soft rot of cabbage, carrot, onion, potato, of flooding during high temperatures tomato, and sweet potato and high humidity. • Target fields where infections have Bacterial stalk rot of corn leaf sheath. Howard F. Schwartz, Bacterial stalk rot symptoms on corn stalks. Howard F. Symptoms: Initially, leaf sheaths on occurred in the past. Colorado State University, Bugwood.org Schwartz, Colorado State University, Bugwood.org corn and stalk nodes become discolored, • Look for blotchy brown lesions on followed by decay. Infected tissue emits a stalks, especially near the base. foul odor and the top of the plant lodges • Avoid wounding potato tubers or or can be easily removed. onions. Onion and potato: soft rot occurs causing infected tissues to dissolve, emit a foul Threat Level: Commonly occurs on odor, and ooze liquid from wounds. Potato potatoes but rarely occurs on corn and tissue can turn black. onion in Utah.

Disease Cycle: Top Management Techniques: • Infections occur during high • Plow corn debris deep into the temperatures (90°F and above) and ground. high relative humidity and when free • Avoid using surface water for moisture is present, such as from rain irrigation (flooding or overhead). or overhead irrigation. When to Consider Treatment: Close-up view of bacterial soft rot damage on a corn Bacterial stalk rot symptoms on a corn stalk. Department of stalk. Howard F. Schwartz, Colorado State University, Bugwood.org Plant Pathology , North Carolina State University, Bugwood.org Time for Concern: Irrigation water There is no cure for infected plants, so that is pumped from a lake, pond, or prevention is key. slow-moving stream can contribute to infections, especially during periods of Look-alikes: none, as symptoms are heat and high humidity. characteristic (foul odor).

Early death of corn plants can be a symptom of Early death of corn plants can be a symptom of bacterial stalk rot. University of Nebraska Lincoln bacterial stalk rot. University of Nebraska Lincoln

106 107 DISEASES DISEASES BACTERIAL DISEASES ZEBRA CHIP DISEASE Caused by: Candidatus Liberibacter solanacearum Spread by: potato psyllids (Bactericera cockerelli) DISEASES BACTERIAL

Hosts: Primarily solanaceous species When and Where to Scout: including eggplant, pepper, potato, • Symptoms on potato can go tobacco, tomato, carrots, and several unnoticed until the potato tubers are solanaceous weeds sliced. Foliar symptoms are often visible but mistaken for nutrient Symptoms: Above-ground symptoms deficiency. include yellowing and a pink-reddish • Scout for potato psyllids using yellow Zebra chip disease is transmitted by adult potato psyllids Zebra chip disease causes foliage of infected plants to discoloration of the foliage, and brown sticky cards starting early in the that carry the bacterium. Whitney Cranshaw, Colorado State University, turn pink to reddish in color. Whitney Cranshaw, Colorado State striations on sliced potato tubers (even season Bugwood.org University, Bugwood.org more pronounced when fried). Tomato: • Inspect undersides of host leaves for Chlorosis of leaves and stunted plants. the presence of psyllid nymphs (see Carrots: Stunted plants with reddish psyllids on pg. 78-79) foliage. • Monitor areas that have had the disease in the past. Disease Cycle: • Infection occurs when disease- Threat Level: The disease occurs across carrying potato psyllids feed on Utah but infection levels vary from year healthy plants. to year. The disease tends to be more • Overwinters in potato psyllids which common in areas that had it in the past. overwinter in warmer locations. Top Management Techniques: Time for Concern: Throughout the • Control psyllids early in the season. growing season. • Remove infected plants. Zebra chip disease symptoms on potato. Whitney Cranshaw, Zebra chip disease symptoms on potato. Whitney Cranshaw, • Application of insecticides; early in Colorado State University, Bugwood.org Colorado State University, Bugwood.org the season to control potato psyllids.

When to Consider Treatment: Consider treatment when potato psyllids are present.

Look-alikes: nutrient deficiency (leaves)

Zebra chip disease results in a brown discoloration of Zebra chip disease is more pronounced on fried the vascular tissue in the potato tuber. Joseph Munyaneza, potatoes. Joseph Munyaneza, Agricultural Research Service, USDA Agricultural Research Service, USDA

108 109 DISEASES DISEASES

BOTRYTIS NECK ROT Caused by: Botrytis acclada and B. allii Spread by: infected seed or germination of soilborne spores

Hosts: chives, garlic, leek, onion, shallot When and Where to Scout:

DISEASES • Since plants are symptomless in FUNGAL Symptoms: Symptoms appear after the field, monitor stored bulbs for onions are placed in storage. Infected softening neck tissue. bulbs may have a sunken appearance and FUNGAL will feel spongy. Scales turn brown at the Threat Level: This disease is usually rare Early stage of botrytis neck rot. Utah State University Advanced decay by botrytis neck rot. Utah State University DISEASES neck, and rot will extend to the basal plate. in Utah, but can occur in high numbers. Gray fungal spores may be seen on the Risk increases if bulbs are harvested when outside of the bulb. wet or not fully cured.

Disease Cycle: Top Management Techniques: • Infections may occur in one of • Bury cull onions. three modes: via infected seed; when • Practice a 3 to 4 year rotation. onion plants come into contact with • Harvest only mature and fully cured resting Botrytis spores in the soil; bulbs. when wind-blown spores infect bulbs during harvest. When to Consider Treatment: • For all the modes of infection noted Late application of a fungicide can above, the pathogen remains latent in decrease infections if it is rainy during the plant until after storage. harvest. • Infections appear on bulbs 1 to 2 months after storage. Look-alikes: none White mycelium of Botrytis growing between scales. "Sclerotia" spores produced by Botrytis on onion bulbs. Utah State University Utah State University Time for Concern: The disease is most severe when there is poor ventilation, high humidity, and temperatures above 40°F in storage.

Grey Botrytis spores produced on onion. Utah State University Onion cull pile with Botrytis lesions caused by Botrytis allii. Howard F. Schwartz, Colorado State University, Bugwood.org

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CORN SMUT Caused by: Ustilago maydis Spread by: windblown or rain-splashed spores

Hosts: sweet and field corn When and Where to Scout:

DISEASES • Inspect succulent corn tissues starting FUNGAL Symptoms: White-gray, fleshy galls in late spring for spongy, gray galls. (swollen plant tissue) form on tassels, corn • Once ears begin to form, pull kernels, leaves, and shoots. When galls back sheaths to check for any gall FUNGAL are young, they can be cooked and eaten. formation on kernels. DISEASES When galls are older, they turn black and Smut on corn ear (top), as compared to a healthy ear. Tassel infected with corn smut. Claudia Nischwitz, Utah State powdery. Threat Level: This disease is rare in Utah, Whitney Cranshaw, Colorado State University, Bugwood.org University but if symptoms develop while ears are Disease Cycle: still growing, ears become unmarketable. • Overwinters as spores in the soil or on infected corn debris. Top Management Techniques: • In late spring, windblown or rain- • Remove and dispose of galls splashed spores cause infections on throughout the season. succulent tissue. • Remove and destroy plant debris in • As galls age, they erupt and release the fall. thousands of spores that drop to the • Rotate crops. soil. When to Consider Treatment: Time for Concern: Plants are most Fungicides will not provide control of commonly infected early in the growing common smut. season, at the active growing points. Look-alikes: none, as symptoms are characteristic (gray to black galls) Stalk infected with corn smut. Clemson University, USDA Leaf infected with corm smut. University of Georgia Plant Pathology Cooperative Extension Slide Series, Bugwood.org Archive, UG, Bugwood.org

Corn smut on sweet corn. Gerald Holmes, California Polytechnic State Corn smut on corn ear. Penn State Department of Plant Pathology & University at San Luis Obispo, Bugwood.org Environmental Microbiology Archives, Penn State University, Bugwood.org

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EARLY BLIGHT Caused by: Alternaria solani Spread by: infected seed or transplants; rain-splashed spores from old plant debris

Hosts: potato and tomato (primarily), When and Where to Scout:

DISEASES as well as eggplant and pepper, and • Starting in mid to late spring, FUNGAL solanaceous weeds such as nightshade regularly check older, lower leaves for circular, brown spots. Symptoms: In Utah, symptoms mainly FUNGAL occur on foliage, whereas elsewhere, fruit Threat Level: Minor, as primarily only DISEASES can also be infected. On foliage, lesions older leaves may be affected. Brown spots on leaves caused by early blight. Utah State Early blight can cause concentric rings to develop when are concentrated on older leaves closer to University spores are reduced. Utah State University the ground. Round, brown spots form, Top Management Techniques: containing distinctive rings and a yellow • Cultivars such as Iron Lady, Mountain margin. On fruits, small spots form that Magic, Jasper, Juliet, and Verona are are dark and leathery. resistant. • Rotate out of tomato/potato for at Disease Cycle: least two years. • Overwinters as spores in infected • Remove infected plants and leaves plant debris and may also be during the season, and after harvest, introduced via infected seed or remove or bury plant debris. transplants. • Rain-splashed spores land on lower When to Consider Treatment: foliage, causing new infections. Many fungicides are available, but rarely Infections can continue throughout need to be used as fruit is typically not the season so long as moisture and infected in Utah. warm temperatures persist. Look-alikes: bacterial spot, late blight Early blight on fruit. Utah State University Early symptoms of early blight on potato leaves. Howard F. Schwartz, Colorado State University, Bugwood.org Time for Concern: Disease develops (except this disease develops under during warm temperatures (optimally, 82 cool conditions, and succulent tissue is to 86°F). susceptible)

A potato leaflet showing early blight symptoms.Howard F. A potato field showing early blight symptoms. Howard F. Schwartz, Colorado State University, Bugwood.org Schwartz, Colorado State University, Bugwood.org

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FUSARIUM WILT Caused by: Formae speciales (special forms) of Fusarium oxysporum Spread by: soil

Hosts: Wide range of vegetables When and Where to Scout:

DISEASES including cantaloupe, eggplant, lettuce, • Watch for symptoms when soil FUNGAL pepper, potato, pumpkin, spinach, tomato, moisture and temperatures are high and watermelon, alfalfa, many ornamentals, (90°F). and weeds such as dandelion, groundsel, • Monitor areas that have had the FUNGAL lamb’s quarters, pigweed, sagebrush, and disease in the past. DISEASES shepherd’s purse Fusarium wilt on tomato plants. William M. Brown Jr., Bugwood.org Fusarium wilt symptoms in a melon field.Howard F. Schwartz, Threat Level: This disease is widespread Colorado State University, Bugwood.org Symptoms: General symptoms include in Utah cantaloupe, pea, and tomato wilt, chlorosis, red to purple discoloration production, occasional in celery, cucumber, of leaves or stems, stunted and/or pumpkin, squash, and watermelon, and distorted growth, necrosis, and premature rare in potato. Chlamydospores can survive plant senescence. Reduced seed production for a several years in the soil and plant or yield may occur. debris.

Disease Cycle: Top Management Techniques: • Infection occurs when fungi infect • Use resistant varieties when available. the roots of host plants. • Plant on raised beds for better water • Overwinters as resting spores called drainage. chlamydospores. • Clean equipment and shoes from • Fusarium wilt is soilborne and attached soil. seedborne. • Use certified disease-free seed. • The pathogen is highly specific. For example, the forma speciales that When to Consider Treatment: Melon plants showing Fusarium wilt symptoms. Howard F. Fusarium wilt symptoms in a field of melons.Howard F. Schwartz, Colorado State University, Bugwood.org Schwartz, Colorado State University, Bugwood.org infects tomato does not infect pepper There are no chemical controls for or any other vegetable. Each forma Fusarium oxysporum. speciales is specific to one crop. Look-alikes: Verticillium wilt, drought Time for Concern: During high soil stress, Phytophthora crown rot moisture and temperatures (90°F).

Wilt diseases cause vascular discoloration. Clemson University - Wilt diseases cause vascular discoloration. Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org USDA Cooperative Extension Slide Series, Bugwood.org

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GUMMY STEM BLIGHT (BLACK ROT) Caused by: Didymella bryoniae Spread by: infected seed and rain-splashed spores from infected plant debris

Hosts: cantaloupe, cucumber, pumpkin, When and Where to Scout:

DISEASES squashes, watermelon, and other melons • Inspect seedlings and transplants for FUNGAL symptoms starting in mid-spring. Symptoms: All above-ground parts of the plant can become infected. Lesions Threat Level: This disease is most FUNGAL on the stem form a brown, cracked area common in Utah on fruit in the field and DISEASES that may ooze a red to amber gummy seedlings produced in greenhouses, where Gummy stem blight (GSB) causes necrotic (dead) spots GSB sometimes causes infected stems to ooze a gummy substance. Leaves develop dark brown humidity is higher. on infected leaves. Clemson University - USDA Cooperative Extension Slide substance. Clemson University - USDA Cooperative Extension Slide Series, circular spots starting at margins. On Series, Bugwood.org Bugwood.org squash fruit, the disease is called black Top Management Techniques: rot, causing large necrotic lesions. On • Rotate out of cucurbit crops for 2-3 butternut squash fruits, the disease may years. form distinct concentric rings. • Remove and destroy infected plants.

Disease Cycle: When to Consider Treatment: • Overwinters in the soil as spores on Several fungicides are available, but should infected plant debris. only be used upon confirmed diagnosis. • Splashing water spreads spores onto susceptible plant tissue. Look-alikes: blossom end rot on fruits

Time for Concern: Optimum conditions for infection range from 65-75°F On squash, the GSB disease is called black rot. Utah State Black rot may form distinct concentric rings on (depending on the crop) and moisture of University butternut squash fruit. Utah State University up to 10 hours.

Gummy stem blight lesions at the base of a watermelon Gummy stem blight vine decline in melon. Gerald Holmes, plant. Don Ferrin, Louisiana State University Agricultural Center, Bugwood.org California Polytechnic State University at San Luis Obispo, Bugwood.org

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PINK ROOT Caused by: Phoma terrestris Spread by: soil; water; mechanical activity

Hosts: Primarily onion but can survive in, When and Where to Scout:

DISEASES but not damage, cereals, corn, cucurbits, • Watch for stunted plants throughout FUNGAL garlic, grasses, pepper, spinach, and the growing season. soybean • Infection is confined to roots and outer scales of the bulb. FUNGAL Symptoms: Infected roots turn a • Pull suspect onions to look for pink DISEASES distinctive pink to red color that later turns roots. Pink root symptoms. Utah State University Aboveground symptoms of pink root. Severely infected dark red or purple. Roots may shrivel and plants appear to have a nutrient deficiency or water die. The fungus spreads to newly produced Threat Level: This fungal disease is stress Utah State University roots which leads to reduced bulb size widespread in Utah onion production. in onions. Infected plants are small and Incidence of disease can worsen when stunted and in severe cases, leaves start to onions are planted after cereals or in very die back resembling drought stress. short rotation with onion. The disease is greatly enhanced when plants are stressed. Disease Cycle: • Infection occurs when the fungus Top Management Techniques: penetrates roots directly without the • Use resistant varieties. need for wounds. • Maintain healthy, vigorous plants. • Once introduced, the pink-root • Rotate crops. fungus can persist indefinitely in the soil. When to Consider Treatment: • Optimum infection occurs at soil Fumigation can be effective against some temperatures of 75-85°F. strains of the fungus but is not always economical because it is very expensive. Symptoms of pink root can cause roots to become Symptoms of pink root. Time for Concern: Throughout the desiccated and shrivel up. Gerald Holmes, California Polytechnic State growing season. Look-alikes: drought stress, nutrient University at San Luis Obispo, Bugwood.org deficiency,Fusarium spp. (pink roots)

Bulb and root showing evidence of pink root. Howard F. Roots will range in color from light to deep pink. David B. Schwartz, Colorado State University, Bugwood.org Langston, University of Georgia, Bugwood.org 120 121 DISEASES DISEASES

POWDERY MILDEW OF CUCURBITS Caused by: Podosphaera xanthii and Erysiphe cichoracearum Spread by: windblown spores

Hosts: all cucurbit crops (melons, When and Where to Scout:

DISEASES pumpkins, squashes) • Early detection is key; begin weekly FUNGAL scouting of the undersides of the Symptoms: White, powdery fungal lower, oldest leaves of the crop soon growth occurs on leaves, stems, and after planting. FUNGAL petioles. Initial infections begin as a few, • Continue scouting up to harvest. DISEASES small, white fungal spots. Eventually, these Spots can be on both upper and lower surfaces of Close-up view of powdery mildew on the underside of spots spread and enlarge throughout the Threat Level: Very common and leaves; note several powdery spots on the underside of squash leaf. Cami Cannon, Utah State University plant. As leaves become colonized, they widespread in Utah. this infected squash leaf. Cami Cannon, Utah State University may turn yellow and wilt, exposing the fruit to sunscald and resulting in poor Top Management Techniques: yield. • Remove early infected leaves as they are encountered. Disease Cycle: • Some resistant cultivars are available, • Infection occurs via windborne especially cucumber. spores that can travel for many miles. • Provide adequate plant spacing. • Remove old plant debris and Time for Concern: Infections may occur volunteers. all season. Temperatures between 75-85°F with high humidity and no rainfall promote When to Consider Treatment: rapid spread. (Humidity that forms within Many fungicides, both organic and the crop is enough for this pathogen.) conventional are available, and must be applied to the as soon as first small white Powdery mildew appears as white powdery spots. Cami Over time, powdery mildew can cover the entire leaf. spots are observed. Continue to apply Cannon, Utah State University Cami Cannon, Utah State University every 7-10 days.

Look-alikes: none, as this disease is characteristic (white spots on leaves)

Powdery mildew symptoms on melon. Utah State University Powdery mildew symptoms on squash. Cami Cannon, Utah State University

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PURPLE BLOTCH Caused by: Alternaria porri Spread by: wind; water

Hosts: garlic, leeks, onion, shallot When and Where to Scout:

DISEASES • Watch for symptoms starting on FUNGAL Symptoms: Early symptoms include older leaves throughout the growing small brown elliptical spots on leaves, season. similar to IYSV lesions, which enlarge over FUNGAL time and may result in brown, necrotic Threat Level: This disease is occasional DISEASES streaks. Lesions will eventually turn purple in Utah onion production. Older leaves are Onion leaf dieback due to purple blotch. Utah State University Purple blotch symptoms on onion. Utah State University as fungal spores develop. In severe cases, more susceptible. lesions enlarge and coalesce to blight the entire leaf. This pathogen requires wounds Top Management Techniques: caused by other diseases (e.g. botrytis), • Rotate crops. thrips feeding, or hail, to enter the plant. • Avoid excessive nitrogen applications. • Bury or dispose of culls and other Disease Cycle: plat debris. • Infection occurs when fungal spores • Application of fungicides. from nearby plants are blown by wind into onion fields where they infect When to Consider Treatment: wounded plants. Use fungicides as soon as the disease has • Overwinters in crop residue on or been confirmed to prevent further spread. near the soil surface. Treatment for purple blotch also controls • Optimum temperatures for infection Stemphylium leaf blight (see Stemphylium are between 77-85°F. leaf blight on pg. 126-127). Purple blotch symptoms on onion. Howard F. Schwartz, Colorado Early leaf symptoms of purple blotch on onion. Howard F. Time for Concern: Throughout the Look-alikes: Iris yellow spot virus State University, Bugwood.org Schwartz, Colorado State University, Bugwood.org growing season. (lesions)

Purple blotch lesion on the neck region of an onion Advanced symptoms of purple blotch on a field of plant . Howard F. Schwartz, Colorado State University, Bugwood.org onion plants. Howard F. Schwartz, Colorado State University, Bugwood.org

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STEMPHYLIUM LEAF BLIGHT Caused by: Stemphylium vesicarium Spread by: windblown spores

Hosts: onion (primarily), as well as chives, When and Where to Scout:

DISEASES garlic, and wild/ornamental onions • Conduct weekly examination of older FUNGAL leaves (which are most susceptible), Symptoms: This disease is limited to starting in mid to late spring. leaves, and does not extend down to the FUNGAL scales of the bulb. Infections are initially Threat Level: This disease is common in DISEASES small, light yellow to brown spots that may Utah onion fields, but rarely causes crop Stemphylium leaf blight symptoms on onion. Claudia Mixed infection of downy mildew and Stemphylium. coalesce into extensive blighting of the loss. Nischwitz, Utah State University, Bugwood.org Claudia Nischwitz, Utah State University, Bugwood.org leaves. Spots turn dark in appearance due to formation of fruiting bodies. Top Management Techniques: • Rotate out of onion crops for at least Disease Cycle: three years. • The pathogen overwinters on • Bury plant debris. infected plant debris. • Reduced plant density. • Spores from outside or within the field are windblown and only cause When to Consider Treatment: infections through existing wounds Fungicides are available to prevent further on the leaf surface, such as from spread; only apply after correct diagnosis. thrips feeding, hail, windstorms, etc. Look-alikes: Iris yellow spot virus, thrips Time for Concern: Optimum conditions feeding, purple blotch, some bacterial leaf for spread are 65 to 77°F, heavy dew or diseases rainfall, and conditions that cause foliar The primary disease is downy mildew. However, some Stemphylium leaf blight on onion. Gerald Holmes, California wounding. Stemphylium leaf blight is also present. Gerald Holmes, Polytechnic State University at San Luis Obispo, Bugwood.org California Polytechnic State University at San Luis Obispo, Bugwood.org

Stemphylium leaf blight in an onion field. Gerald Holmes, Onion umbel stalk showing a lesion caused by California Polytechnic State University at San Luis Obispo, Bugwood.org Stemphylium . Gerald Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.org 126 127 DISEASES DISEASES

VERTICILLIUM WILT Caused by: Verticillium dahliae Spread by: soil

Hosts: Wide range of vegetables When and Where to Scout:

DISEASES including cantaloupe, eggplant, pepper, • Watch for symptoms during cooler FUNGAL potato, pumpkin, spinach, tomato, and temperatures (68-74°F). watermelon, stone fruit trees, alfalfa, many • Symptoms are often expressed ornamentals, and weeds such as dandelion, on one side of a plant, branch, or FUNGAL groundsel, lamb’s quarters, pigweed, leaflets. DISEASES sagebrush, and shepherd’s purse • Symptoms may not appear until the Close up of distinctive, one-sided chlorotic (yellow) Necrosis (brown dead tissue) and chlorosis (yellow host initiates flowering. leaf next to healthy leaf on the left. Gerald Holmes, California tissue) in tomato caused by verticillium wilt. Gerald Holmes, Symptoms: General symptoms include Polytechnic State University at San Luis Obispo, Bugwood.org California Polytechnic State University at San Luis Obispo, Bugwood.org wilt, chlorosis, red to purple discoloration Threat Level: This disease is widespread of leaves or stems, brown discoloration in Utah cantaloupe, eggplant, pepper, inside vascular tissue, stunted overall potato, and tomato production and growth, foliar necrosis, and premature occasional in squash and pumpkin. plant senescence. Reduced seed production Microsclerotia can survive for a decade or or yield may occur. more in the soil, waiting for a suitable host to be planted. Disease Cycle: • Infection occurs when fungi infect Top Management Techniques: the roots of host plants • Use resistant varieties when available. • Overwinters as a survival structure • Plant on raised beds for better water called a microsclerotium (hard black drainage. ball of fungal tissue) • Verticillium wilt is soilborne. When to Consider Treatment: There are no chemical controls for Foliar symptoms of Verticillium wilt on eggplant. Gerald Wilted tomato plants show symptoms of verticillium Verticillium wilt. Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.org wilt. Gerald Holmes, California Polytechnic State University at San Luis Obispo, Time for Concern: Throughout the Bugwood.org growing season; especially if vegetables are planted in fields that previously had alfalfa. Look-alikes: other wilt diseases, such as Fusarium wilt, drought stress

Verticillium wilt occasionally causes discoloration of the Verticillium wilt causes discoloration of the vascular potato tuber vascular tissue. University of Minnesota Extension tissue in the main stem of the host plant. University of Minnesota Extension 128 129 DISEASES DISEASES

LATE BLIGHT Caused by: Phytophthora infestans Spread by: infected seedlings; splashing water; field equipment and tools

Hosts: potato, tomato, and related weeds When and Where to Scout: such as nightshade and bittersweet • Start scouting for this disease soon after planting. Early detection is Symptoms: All above-ground portions important; as rapid spread can occur. of plants can be infected, plus potato • Check wet areas of the field first tubers. Lesions on leaves and stems start (low spots in the field, edges near as a greasy-gray blotch, and eventually turn hedgerows, shaded areas, etc.). New late blight lesions may have a yellow halo. William M. Late blight lesions quickly enlarge and turn black-

FUNGAL-LIKE black. Infected tomato fruits and potatoes Brown Jr., Bugwood.org brown. Howard F. Schwartz, Colorado State University, Bugwood.org DISEASES develop hard, brown, blotchy lesions that Threat Level: Epidemics are rare and extend into the flesh. localized in Utah.

Disease Cycle: Top Management Techniques: DISEASES • Overwinters in infected potato tubers • Eliminate cull piles, plant debris, and FUNGAL-LIKE left underground or in cull piles. volunteer potato and tomato plants. • Under wet conditions, spores form • Once the disease is detected, in early spring and are carried for immediately remove and destroy miles to cause primary infections on infected plants. succulent plant tissue. Storms from • Avoid overhead irrigation and southern states can also contribute to excessive nitrogen applications. spread of spores. • Rotate out of tomato or potato for • Later in the season, infected tissue two years. releases additional spores, causing new secondary infections and When to Consider Treatment: sometimes, epidemics can wipe out Fungicides are necessary where the disease Tubers infected with late blight decay either in the soil Late blight leaf symptoms. Utah State University or in storage. Sandra Jensen, Cornell University, Bugwood.org entire fields. has occurred in the past.

Time for Concern: When leaves are wet Look-alikes: early blight (leaf lesions for more than 10 to 12 hours at moderate instead have concentric rings, and this temperatures (60-80°F). disease develops under warm conditions on older foliage)

Late blight appearing as a white mold on leaves. Utah State Late blight causes brown or olive-colored lesions on University fruit. Utah State University

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PHYTOPHTHORA FRUIT ROT Caused by: Phytophthora spp. Spread by: spores in splashing water; field equipment and tools

Hosts: fruits of melon, pumpkin, squash When and Where to Scout: • A few weeks before harvest, inspect Symptoms: Water-soaked spots form fruits each week, by checking where where fruit touches the ground, eventually they touch the soil. turning into a white, yeast-like growth, and finally becoming a soft decay. The fruit will Threat Level: Rare in Utah. collapse. Phytophthora fruit rot symptoms on cucumbers. Charles Phytophthora fruit rot symptoms on melon. Jason Brock,

FUNGAL-LIKE Top Management Techniques: Averre, North Carolina State University, Bugwood.org University of Georgia, Bugwood.org DISEASES Disease Cycle: • Rotate with non-host crops for two • The pathogen survives in soil up to years. two years on infected plant debris. • Plant only in well-drained soils and

• In saturated soils, spores form and allow soil to dry between irrigations. DISEASES may infect nearby fruit that is close to • Clean equipment and tools between FUNGAL-LIKE harvest stage. fields. • Remove infected fruits. Time for Concern: When soil remains saturated for at least five hours toward When to Consider Treatment: harvest time. Under good preventive practices, fungicides are not necessary in Utah.

Look-alikes: blossom end rot

Phytophthora fruit rot symptoms on melon. Jason Brock, Phytophthora fruit rot symptoms on melon. Jason Brock, University of Georgia, Bugwood.org University of Georgia, Bugwood.org

Phytophthora fruit rot symptoms on squash. Gerald Holmes, Phytophthora fruit rot symptoms on squash. Gerald Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.org California Polytechnic State University at San Luis Obispo, Bugwood.org

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PHYTOPHTHORA ROOT/STEM/CROWN ROT Caused by: Phytophthora spp. Spread by: soil; water; mechanical activity

Hosts: tomato, pepper, eggplant, other When and Where to Scout: vegetables, fruit trees, nut trees, and • Watch for symptoms starting early in ornamental shrubs and trees the season. • Watch for poorly draining soil Symptoms: Phytophthora root, stem, throughout the growing season. and crown rot is caused by several species of soilborne pathogens in the genus Threat Level: This disease is sporadic Lower stem lesion on pepper caused by Phytophthora. Young pepper plant is wilting due to girdling of lower

FUNGAL-LIKE Phytophthora. This disease is favored in Utah and is promoted primarily by wet Gerald Holmes, California Polytechnic State University at San Luis Obispo, stem by Phytophthora . Gerald Holmes, California Polytechnic State DISEASES primarily by wet soil but can be favored soil. Warm temperatures may also promote Bugwood.org University at San Luis Obispo, Bugwood.org by warm temperatures as well. Early this disease. infections cause seeds or seedlings to

appear bruised, soft, rotted, yellow, brown, Top Management Techniques: DISEASES and plants can wilt and die. Mid or late • Provide good soil drainage and water FUNGAL-LIKE season infections cause chocolate-brown management to prevent standing lesions on roots and sometimes stems, water. yellowing leaves, wilting, and plant death in • Rotate crops. patches or sections of rows. • Avoid planting susceptible crops in soil infested with Phytophthora. Disease Cycle: • Use resistant varieties when available. • Phytophthora organisms thrive, grow, reproduce, and infect plant roots in When to Consider Treatment: water, saturated soil, and along river Disease is difficult to suppress, so banks and ponds. prevention and cultural controls are key. • Soil-inhabiting pathogens survive as Phytophthora on lower stem of bell pepper. Don Ferrin, Phytophthora root rot in alfalfa field. Sherm Thomson, Utah State Louisiana State University Agricultural Center, Bugwood.org University resting spores in the soil for years Look-alikes: mechanical injury, when there are no suitable hosts. overwatering, insect injury, drought stress, • Water in soil pores and root exudates damping off (seeds and seedlings), stem from plant host nearby allow resting canker (mid or late season) spores to germinate.

Time for Concern: Throughout the growing season.

Phytophthora symptoms on tomato. Gerald Holmes, California Phytophthora stem rot on eggplant. Gerald Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.org Polytechnic State University at San Luis Obispo, Bugwood.org

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ROOT-KNOT NEMATODES Meloidogyne hapla Meloidogyne incognita Meloidogyne chitwoodi

Hosts: Hundreds of plants including Threat Level: Root-knot nematodes are fruits, grasses, vegetables, potatoes, and occasional in Utah. numerous weeds Top Management Techniques: Symptoms: Root-knot nematodes are • Use tolerant varieties when available. microscopic roundworms that enter plants • Keep infested fields fallow for 2-3 Galled root system of tomato infected with root-knot Onion infected with root-knot nematodes (bottom) through the root tips and move up in the years. nematode (left), compared with non-infected root compared to non-infected onion (top). Jonathan D. Eisenback, root until they find a preferred spot to • Remove all weeds. system (right). Jonathan D. Eisenback, Virginia Polytechnic Institute and State Virginia Polytechnic Institute and State University, Bugwood.org University, Bugwood.org feed. They feed by releasing chemicals • Roto-till fallow areas once every 3-4 that cause cell nuclei to divide without weeks during the hot, dry summer cell division, creating giant feeding cells. months. Above-ground symptoms are chlorosis and • Telone soil fumigation in commercial stunting resembling nutrient deficiency. fields. Roots of infected plants have galls. Large galls can merge to look like one big tumor. When to Consider Treatment: Except fumigation for commercial fields, Disease Cycle: there are currently no chemical options for • Infection occurs when root-knot root-knot nematode control. nematodes enter the plant through NEMATODE-CAUSED the roots. Look-alikes: nitrogen fixing nodules • Overwinter as juveniles in the soil. (Rhizobium) on roots of legume family DISEASES plants (confused with galls), drought Time for Concern: Throughout the stress (aboveground), excessive water Deformed root system of carrot caused by root-knot Galled roots of beet caused by root knot nematode. (aboveground), extreme soil pH nematode. Jonathan D. Eisenback, Virginia Polytechnic Institute and State Gerald Holmes, California Polytechnic State University at San Luis Obispo, growing season, but control measures are University, Bugwood.org Bugwood.org

only effective before or at planting. (aboveground), extreme soil texture DISEASES differences (aboveground)

When and Where to Scout: NEMATODE-CAUSED • Root-knot nematode problems are often discovered after finding galled roots on a previous crop. • A simple bioassay can be used to detect root-knot nematodes in the soil or a sample can be sent for testing to a nematology lab.

Potatoes showing damage caused by root knot Root knot nematodes in potato tuber. Elizabeth Bush, Virginia nematode. William M. Brown Jr., Bugwood.org Polytechnic Institute and State University, Bugwood.org

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ALFALFA MOSAIC VIRUS (AMV) Genus: Alfamovirus Caused by: Alfalfa mosaic virus Spread by: aphids; alfalfa and pepper seed; mechanical activity

Hosts: alfalfa, basil, bean, birdsfoot When and Where to Scout: trefoil, clover, lettuce, hairy vetch, pea, • Watch for symptoms on vegetables pepper, potato, tomato, and weeds throughout the growing season. including bindweed, lambsquarter, • Monitor aphid activity throughout nightshade weeds, perennial sowthistle, the growing season, especially near pigweed, purslane, shepherd’s purse alfalfa. Alfalfa mosaic virus symptoms on alfalfa. Mary Ann Hansen, Alfalfa mosaic virus symptoms on potato leaves. Howard F. Virginia Polytechnic Institute and State University, Bugwood.org Schwartz, Colorado State University, Bugwood.org Symptoms: Yellow mosaic or calico Threat Level: Generally, not a major patterns, turning to a bronze discoloration problem in Utah but can occur in localized on leaves, necrotic phloem tissues, necrotic areas each year and can cause significant rings and spots on fruit, sometimes solid losses in potatoes planted next to alfalfa. brown necrosis on surface of fruit, and usually plant death. Top Management Techniques:

DISEASES • Avoid planting susceptible vegetables VIRAL Disease Cycle: near alfalfa or clover. • Aphids acquire the virus by feeding • Use reflective mulches to repel on an infected plant (commonly aphids. VIRAL alfalfa) and transmit it when feeding DISEASES on healthy plants. When to Consider Treatment: • Can be spread through seeds (in No effective chemical controls are alfalfa and pepper) and mechanical currently available. activity. • Overwinters in perennial host plants. Look-alikes: Tomato spotted wilt virus Alfalfa mosaic virus symptoms on potato leaves. Howard F. Alfalfa mosaic virus symptoms on pepper leaves. Cami Schwartz, Colorado State University, Bugwood.org Cannon, Utah State University

Time for Concern: When vegetables are planted near alfalfa, clover, or other legume crops.

Alfalfa mosaic virus symptoms on pepper leaves. Cami Alfalfa mosaic virus symptoms on pepper leaves. Cami Cannon, Utah State University Cannon, Utah State University

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CURLY TOP VIRUS (CTV) Genus: Curtovirus Caused by: Beet curly top virus, Beet severe curly top virus, Beet mild curly top virus, Spinach severe curly top virus, Horseradish curly top virus, Pepper yellow dwarf virus Spread by: beet leafhopper (Circulifer tenellus); potato seed pieces

Hosts: bean, beets, cucurbits (melon, When and Where to Scout: squash, gourds, cucumber), flax, pepper, • Watch for symptoms on vegetables potato, spinach, Swiss chard, tomato, and starting in spring. weeds such as filaree, kochia, lambsquarter, mustards, pigweed, plantain, Russian Threat Level: Widespread across Utah. Beet leafhoppers vector and spread curly top virus. G. Tomatoes infected with curly top are stunted, yellow, thistle, and shepherd’s purse Infection is sporadic and unpredictable Oldfield, USDA, Bugwood.org and have premature fruit. Cami Cannon, Utah State University and is especially threatening to tomato Symptoms: Infected plants occur production in Utah. randomly due to sporadic movement of the beet leafhopper as it feeds. Some Top Management Techniques: plants may exhibit severe symptoms, while • Exclude leafhoppers with floating others are asymptomatic (many species row cover (only effective on small

DISEASES of weeds). Plants affected early in their scale areas with little wind). VIRAL growth may quickly die. Symptoms include • Shade plants. small, twisted, curled leaves with purple • Remove infected plants immediately veins, thickened, stiff, and crisp leaves, upon detection. VIRAL DISEASES yellowing and death of mature leaves, small fruits that ripen prematurely, reduced When to Consider Treatment: fruit quality and yield, stunted growth, and There are no chemical control options downward curling petioles. for curly top and insecticide applications directed at beet leafhoppers are ineffective. Disease Cycle: Infection occurs randomly and has no distinct pattern. Infected tomatoes may develop purple veins in some Cami Cannon, Utah State University leaves. Cami Cannon, Utah State University • Beet leafhoppers acquire the virus Look-alikes: Tomato spotted wilt virus when feeding on infected weeds or (early in the season) other plants and transmit it when feeding on healthy plants. • Can be spread via potato seed pieces. • Overwinters in living host plants and beet leafhopper.

Time for Concern: Spring and summer.

Leaves become thick, stiff, crisp, and curled. Cami Cannon, Premature death and ripening of a tomato plant infected Utah State University with curly top. Cami Cannon, Utah State University

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CURLY TOP VIRUS (CTV) (CONT.) Genus: Curtovirus Caused by: Beet curly top virus, Beet severe curly top virus, Beet mild curly top virus, Spinach severe curly top virus, Horseradish curly top virus, Pepper yellow dwarf virus Spread by: beet leafhopper (Circulifer tenellus); potato seed pieces

Stunted pepper plant (left) infected with curly top. Cami Curly top symptoms on pepper leaves. Cami Cannon, Utah State Cannon, Utah State University University DISEASES

VIRAL Curly top symptoms on bean. Cami Cannon, Utah State University Curly top symptoms on bean. Cami Cannon, Utah State University VIRAL DISEASES

Curly top symptoms on squash. Cami Cannon, Utah State University Curly top symptoms on squash. Cami Cannon, Utah State University

Curly top symptoms on bean leaves. Cami Cannon, Utah State Curly top symptoms on bean. Howard F. Schwartz, Colorado State University University, Bugwood.org

Sugar beet infected with Beet curly top virus showing Sugar beet infected with Beet curly top virus showing foliar chlorosis and curling of leaves. Oliver T. Neher, The foliar chlorosis. Oliver T. Neher, The Amalgamated Sugar Company, Amalgamated Sugar Company, Bugwood.org Bugwood.org

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HIGH PLAINS VIRUS (WHEAT MOSAIC VIRUS) Genus: Emaravirus Caused by: High plains virus / Wheat Mosaic Virus Spread by: wheat curl mite (Aceria tosichella); seedborne in corn

Hosts: barley, corn, oats, rye, wheat, wild When and Where to Scout: grasses, and weeds such as cheatgrass, • Look for yellow streaking or mosaic downy brome, hare barley, jointed patterns on young corn leaves starting goatgrass, and volunteer wheat in spring.

Symptoms: Initial symptoms are stunting Threat Level: High risk sweet corn High plains virus symptoms on a corn leaf. William M. Brown High plains virus symptoms on a corn leaves. Howard F. and a mosaic pattern on leaves. As includes sweet corn grown for seed, late Jr., Bugwood.org Schwartz, Colorado State University, Bugwood.org symptoms progress, yellow stripes, up to May and early June emerging commercial an inch wide, can be observed on leaves of sweet corn planted adjacent to wheat infected plants and in some cases, purple that is between heading and hard dough streaks are observed. growth stage, and commercial sweet corn near winter annual grasses that have not Disease Cycle: matured yet. Especially problematic when

DISEASES • The source of both wheat curl mites no-till or strip till is used and crop rotation VIRAL and the virus is typically volunteer is between corn and wheat. wheat or grasses in ditches. • Virus transmission occurs when Top Management Techniques: VIRAL wheat curl mites feed on host plants. • Remove volunteer wheat and grass DISEASES • Overwinters in winter annual grasses. weeds. • Plant seed early in the season before Time for Concern: Throughout the wheat dries down. growing season. When to Consider Treatment: High plains virus symptoms on a corn leaves. Howard F. High plains virus symptoms on a corn leaves. William M. Schwartz, Colorado State University, Bugwood.org Brown Jr., Bugwood.org There are no effective chemical control options.

Look-alikes: genetic mutation (striping)

Corn showing symptoms of High plains virus. William M. Corn plants showing severe symptoms of High plains Brown Jr., Bugwood.org virus . William M. Brown Jr., Bugwood.org

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IRIS YELLOW SPOT VIRUS (IYSV) Genus: Tospovirus Caused by: Iris yellow spot virus Spread by: onion thrips (Thrips tabaci)

Hosts: onion, garlic, chives, wild/ ornamental onions, pigweed, lambsquarter, When and Where to Scout: iris, kochia, prickly lettuce, blue toadflax, • Monitor thrips populations with geranium, petunia, purslane, roses, sticky traps starting in June. puncturevine, vetch, black-eyed pea, • Damage is often first noticed at field sowthistle edges, in areas of stressed plants, or Iris yellow spot virus lesion with green island on onion. Iris yellow spot virus lesion on onion. Utah State University in locations with thin plant stands. Cynthia Ocamb, www.pnwhandbooks.org Symptoms: A range of lesions can • Infected plants may not show occur including concentric oblong light symptoms for several weeks. oval-shaped rings (early sign), light green • Sometimes symptoms may never diamond-shaped areas, concentric green appear. and tan oval-shaped rings, tan necrotic • Reduced bulb size and quality of spots, and green islands within tan necrotic symptoms develop while bulbs are

DISEASES spots. Damage can reduce harvest yield still growing. VIRAL and grade of onions. Threat Level: This virus is common Disease Cycle: in Utah and can devastate an onion field VIRAL • Infection occurs when virus-carrying (especially for commercial production) DISEASES thrips feed on healthy plants. by reducing bulb size, yield, and grade of • Disease likely overwinters from onions at harvest. one season to the next in volunteer onions and overwintering thrips. Top Management Techniques: • Control thrips (see thrips on pg. 80- Iris yellow spot virus lesions on onion. Cami Cannon, Utah State Iris yellow spot virus lesions on onion. Cami Cannon, Utah State University University Time for Concern: June through 81). September. • Control weeds and volunteer onion plants. • Remove and destroy infected plants. • Rotate crops.

When to Consider Treatment: There is no cure for infected plants, so prevention is key.

Look-alikes: Cladosporium fungal infection in onions, purple blotch, downy mildew, Tomato spotted wilt virus, hail

Iris yellow spot virus field symptoms.Howard F. Schwartz, Severe leaf dieback due to iris yellow spot virus. Utah State Colorado State University, Bugwood.org University

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POTATO VIRUS Y (PVY) Genus: Potyvirus Caused by: Potato virus Y Spread by: aphids; tuber seed pieces; volunteer potato plants; weed hosts; water (in hydroponic systems)

Hosts: Solanaceous plants including When and Where to Scout: potato, tomato, pepper, tobacco, eggplant • Watch for symptoms throughout the and solanaceous weeds such as nightshade growing season. and ground cherry • Monitor aphid activity throughout the growing season. PVY symptoms on potato. Bruce Watt, University of Maine, Bugwood. PVY symptoms on potato. Bruce Watt, University of Maine, Bugwood. Symptoms: There are three strains: org org PVYO, PVYN, and PVYNTN. Symptoms Threat Level: PVY symptoms lead to vary depending on the strain. PVYO yield reduction and loss of tuber quality. causes mosaic symptoms on the leaves This disease is one of the most serious and no symptoms on the tubers. PVYN challenges facing seed potato producers. causes necrotic spots on leaves and tubers. PVYNTN causes necrotic lesions on leaves Top Management Techniques:

DISEASES and necrotic ringspots on the tuber surface • Remove infected plants. VIRAL that extend into the flesh. Infected plants • Use certified seed potatoes that have are typically stunted. been tested for PVY and have more than 90% guarantee to be disease VIRAL Disease Cycle: free. DISEASES • In Utah, infection most frequently • Control weeds and alternative hosts. occurs when infected seed pieces are introduced into a field. The disease is When to Consider Treatment: then spread within a field and beyond Insecticide applications to control aphids by aphids and farm equipment. are ineffective. Potato virus Y (PVY) causes mosaic symptoms and PVY symptoms on potato tuber. Bruce Watt, University of Maine, necrotic spots on potato leaves. Utah State University Bugwood.org • Overwinters in infected seed pieces and in solanaceous weeds (e.g. Look-alikes: none nightshade, ground cherry).

Time for Concern: Throughout the growing season.

PVY necrotic ringspots extend into the flesh of potato PVY causes necrotic ringspots on the potato tuber tubers. Utah State University surface. Utah State University

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TOBACCO MOSAIC VIRUS (TMV) TOMATO MOSAIC VIRUS (ToMV) PEPPER MILD MOTTLE VIRUS (PMMoV) TOMATO MOTTLE MOSAIC VIRUS (TMoMV) Genus: Tobamovirus Caused by: Tobacco mosaic virus, Tomato mosaic virus, Pepper mild mottle virus, Tomato mottle mosaic virus Spread by: seed; artificial grafting; human handling (hands, clothing, tools, tobacco cigarettes and chew); soil; infected plant touching healthy plant; occasionally chewing insects ToMV or TMV mosaic patterned lesions on an infected ToMV or TMV mosaic patterned lesions on an infected tomato plant. Cami Cannon, Utah State University tomato plant. Cami Cannon, Utah State University Hosts: tobacco, tomato, other When and Where to Scout: solanaceous plants, and hundreds of other • Watch for symptoms throughout the plants growing season. • Symptoms vary depending on the age Symptoms: A wide range of symptoms of the infected plant, environmental include abnormally shaped fruit, fruit conditions, virus strain, and genetic DISEASES lesions, reduced fruit size, distorted background of the host plant. VIRAL growing points, abnormal color (often yellowing), form, and patterns on leaves, Threat Level: TMV and ToMV are VIRAL

distorted stems, and distortion and widespread in Utah tomato production DISEASES dwarfing of the plant as a whole. and can survive for up to 50 years in plant debris and for weeks to months on trellises Disease Cycle: or wooden stakes. • Infection occurs when the virus enters the plant through wounds as Top Management Techniques: ToMV or TMV mosaic patterned lesions on an infected TMV can cause fruit tissues to be discolored. Claudia small as torn plant hairs. • Remove infected plants immediately. tomato plant. Cami Cannon, Utah State University Nischwitz, Utah State University • TMV, ToMV, PMMoV, and TMoMV • Use certified disease-free seed. are seedborne. • Use resistant varieties (found online • Overwinters in seed coats, plant by searching “Cornell table of disease debris, perennial (weedy) hosts, and resistant varieties”). soil. When to Consider Treatment: Time for Concern: Throughout the There are no chemical controls for TMV growing season. and ToMV.

Look-alikes: none

Brown sunken lesions are also symptoms of TMV. Claudia Tomato mosaic virus can cause yellow rings to appear. Nischwitz, Utah State University Claudia Nischwitz, Utah State University

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TOMATO SPOTTED WILT VIRUS (TSWV) Genus: Tospovirus Caused by: Tomato spotted wilt virus Spread by: thrips (western flower thrips: Frankliniella occidentalis and onion thrips: Thrips tabaci); infected plant material

Hosts: Over 1,000 known hosts When and Where to Scout: including a wide range of vegetables such • Watch for symptoms throughout the as artichoke, bean cauliflower, celery, growing season. cucumber, eggplant, lettuce, pepper, • Monitor thrips activity throughout potato, spinach, and tomato, ornamentals, the growing season. Tomato spotted wilt virus (TSWV) symptoms on TSWV causes chlorotic ring spot patterns. Utah State and weeds such as buttercup, dandelion, • Monitor fields that had the virus in tomato foliage. Nancy Gregory, University of Delaware, Bugwood.org University lambsquarter, shepherd’s purse, and the past. sowthistle Threat Level: This virus is occasional in Symptoms: Symptoms of TSWV vary Utah tomato production but is becoming between plant species and within a species more widespread. Once a plant is depending on the strain of the virus, time infected there is no cure, and if thrips are

DISEASES of infection, and plant variety. Infected reproducing on the plant, it can serve as VIRAL plants are commonly stunted (generally an inoculum source for neighboring plants. more severe when young plants are The virus is more likely to occur in fields infected). Leaves have necrotic spots, fruit that have had it in the past. VIRAL may form necrotic rings, and seeds may DISEASES become discolored (although TSWV is not Top Management Techniques: seed transmitted). Mature fruit has calico • Control thrips (see thrips on pg. 80- patterns. 81). • Remove and destroy infected plants. Disease Cycle: • Purchase healthy transplants. TSWV can also appear as ring spots on peppers. Utah State TSWV on immature tomato fruit. Utah State University University • Infection occurs when thrips carrying • Use resistant varieties. the virus feed on a healthy plant. • Control weeds. • Overwinters in winter weed species and thrips. When to Consider Treatment: There are no chemical controls for TSWV. Time for Concern: Throughout the growing season. Look-alikes: Curly top virus (early in the season), Alfalfa mosaic virus

Blotchiness on tomatoes caused by TSWV. Utah State Brown ring spots on TSWV infected mature fruit. Utah University State University

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WATERMELON MOSAIC VIRUS (WMV) Genus: Potyvirus Caused by: Watermelon mosaic virus Spread by: aphids

Hosts: bean, cucumber, gourds, pea, When and Where to Scout: pumpkin, squash, watermelon, winter • Watch for symptoms starting in June squash, and weeds such as lambsquarter, until the end of the season. mallow, and shepherd's purse • First symptoms are often seen on field edges. Symptoms: Symptoms include stunting, • Monitor aphid activity starting in Watermelon mosaic virus (WMV) symptoms on squash WMV symptoms on squash fruit. Cami Cannon, Utah State leaf malformation, yellowing or light green June. leaf. Cami Cannon, Utah State University University mottling, marginal chlorosis, and dwarfed, mottled, or spotted fruit. Fruit may also Threat Level: This disease is widespread form warts, or raised blister-like areas. in Utah watermelon and squash production and occasional in cantaloupe. Disease Cycle: • Infection occurs when virus-carrying Top Management Techniques:

DISEASES aphids feed on healthy plants. • Control weeds. VIRAL • Overwinters in perennial weeds or • Rotate crops. alfalfa. • Use resistant varieties when available. VIRAL DISEASES Time for Concern: June (or earlier if When to Consider Treatment: winter was mild or crops are grown in high Insecticides for aphids are of limited value tunnels) until the end of the season. to control this disease.

Look-alikes: herbicide damage (leaves) Aphid infestation on squash infected with WMV. Cami Malformed leaves and stems of squash infected with Cannon, Utah State University WMV. Cami Cannon, Utah State University

Watermelon mosaic virus (WMV) symptoms on squash WMV symptoms on pumpkin fruit. Cami Cannon, Utah State leaf. Cami Cannon, Utah State University University

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BLOSSOM END ROT (BER) Caused by: lack of calcium Spread by: n/a

Hosts: pepper and tomato (primarily); When and Where to Scout: also occurs on apples, cucumber, melons, • Watch developing green fruits after and squash prolonged periods of dry soils.

Symptoms: Symptoms only occur at the Threat Level: Common in Utah, but blossom end of the fruit, where the skin usually only a few fruits per plant may be and inner flesh become leathery and turn affected. Blossom end rot (BER) symptoms on tomato fruit. Cami BER symptoms on tomato fruit. Cami Cannon, Utah State dark brown to black. Symptoms may occur Cannon, Utah State University University at any stage in the development of the Top Management Techniques: fruit, but most commonly, are first seen • Keep the soil evenly moist when the fruit is one-third to one-half full throughout the growing season. size. • Cultivate the soil or add mulch to prevent compaction. Disease Cycle: • Prevent root disturbance. • This disease is not infectious, and is related to calcium availability in the When to Consider Treatment: plant. Since it is of a physiological nature, • The primary issue in Utah is having prevention is key. enough water to carry the calcium to the plant. Water flow may be Look-alikes: none, as symptoms are compromised by drought, root characteristic (dark, leathery skin at disturbance, and compacted soils. blossom end)

BER symptoms on tomato fruit. Cami Cannon, Utah State BER symptoms on pepper fruit. Paul Bachi, University of Kentucky Time for Concern: The disease is University Research and Education Center, Bugwood.org especially prevalent when rapidly growing, succulent plants are exposed suddenly to a period of drought. DISORDERS ABIOTIC ABIOTIC DISORDERS

BER symptoms on squash fruit. Gerald Holmes, California BER symptoms on melon fruit. Gerald Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.org Polytechnic State University at San Luis Obispo, Bugwood.org

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HERBICIDE DAMAGE Caused by: misapplication of herbicides (e.g. dicamba, 2,4-D, atrazine); herbicide drift or volatilization; herbicide leaching or run-off; contaminated soil amendments Spread by: n/a

Hosts: Any plant common broadleaf herbicides 2,4-D or dicamba, while others can be severely Symptoms: Symptoms include twisted damaged and can even die from a little or bent stems and leaf petioles, cupped drift or residue in the tank. In severe leaves, abnormal growth, yellowing and situations with soil applied herbicides, soil

browning leaves, dead plant parts, dotted removal may be necessary. Herbicide damage on melon. Cami Cannon, Utah State University Herbicide damage on melon. Cami Cannon, Utah State University or speckled necrosis, stunted plant growth, narrow leaves, and chlorosis around leaf Top Management Techniques: margins and interveinal areas of leaves. • Apply herbicides only when necessary Seedlings may fail to emerge and plants and carefully follow the label. wilt and die. • Be especially careful with soil sterilizers; susceptible roots can grow Disease Cycle: beyond expected areas. • n/a • Exercise best management practices to reduce or eliminate the need for Time for Concern: Following application herbicides. or misuse of herbicides. It is also good • Wash with water, plant foliage that to monitor plants for a few weeks after has been exposed to spray or drift. manure or compost applications. • Apply activated charcoal to soil where soil-active herbicides were used. When and Where to Scout: • Spread dust or soil on exposed plant • Herbicide damage can be difficult to surfaces to detoxify glyphosate. isolate. • Ensure compost comes from a Herbicide damage on onion. Howard F. Schwartz, Colorado State Herbicide damage on tomato. Rebekah D. Wallace, University of University, Bugwood.org Georgia, Bugwood.org • Identify by eliminating other reliable source and has not been possibilities. contaminated by herbicides. • Look for distorted growth and chlorosis or necrosis on leaves and/ When to Consider Treatment: or stems. Once a plant has been exposed, no DISORDERS

ABIOTIC • Look for a lack of weeds or bare treatments are available beyond good plant ground in areas near damaged plants care. (implying recent herbicide or soil Look-alikes: distorted growth on

sterilizer application). ABIOTIC

• Watch for areas where multiple plants leaves and/or stems, nutrient deficiencies DISORDERS of different species show the same (chlorosis) in leaves, bleached leaves, symptoms. sections of plant decline while other sections of the plant are healthy, salt Threat Level: Depending on the plant damage, chronic fungal infections in roots species, some landscape and garden plants that cause nutrient and water uptake issues, Herbicide damage on potato. Jed Colquhoun, University of Wisconsin, Herbicide damage on corn. Utah State University are not killed by minimal exposure to the heat scorch, Watermelon mosaic virus Bugwood.org

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NUTRIENT DEFICIENCIES Caused by: lack of nutrients. In Utah vegetable production, the most common nutrient deficiencies that may impede yield are lack of phosphorus or nitrogen (macronutrients). Potassium deficiency may occur in very light, well-drained sandy or gravelly soils. Micronutrients such as iron and zinc are not available in Utah soils for uptake, but this does not affect vegetable production. Spread by: n/a

Hosts: all vegetable crops can be affected Top Management Techniques: • Add moisture after spring fertilizing.

Symptoms: Nitrogen deficiency – • Conduct regular soil testing to Nitrogen deficiency in cucumber.Gerald Holmes, California Phosphorus deficiency in lettuce.North Carolina State University slow growth, light green foliar color, low determine whether phosphorus, Polytechnic State University at San Luis Obispo, Bugwood.org yields and poor plant quality. Phosphate potassium, or other nutrients need to deficiency - dark green foliar color, with be applied. purpling on leaf undersides, stunted plants • Enhance soil health by applying and reduced yields. amendments, such as manure (in fall), compost, or use cover crops. Disease Cycle: • n/a When to Consider Treatment: Annually for nitrogen, and as soil test Time for Concern: Apply fertilizer results require for other nutrients. before or at planting. Look-alikes: many different conditions When and Where to Scout: may mimic nutrient deficiency, such as • Check plants throughout the growing wilts, viruses, herbicide injury, frost injury, season for change in foliage color and and more stunting. Nitrogen deficiency in corn. Felix Francis, University of Delaware, Phosphorus deficiency in corn. Bugwood.org Threat Level: Annual applications of phosphorus can lead to excessively high amounts which can cause micronutrient availability problems. DISORDERS ABIOTIC ABIOTIC DISORDERS

Nutrient deficiency in beans.Howard F. Schwartz, Colorado State Nutrient deficiency in beans.Howard F. Schwartz, Colorado State University, Bugwood.org University, Bugwood.org

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SUNSCALD Caused by: intense solar radiation; low humidity; reflected heat Spread by: n/a

Hosts: bean, cucumber, eggplant, pea, Threat Level: Sunscald is widespread in pepper, summer squash, sweet corn, Utah tomato and pepper production. tomato, melons, and other fruits Top Management Techniques: Symptoms: Large, light-colored blistered • Develop and maintain a good leaf areas develop on the sides of fruits facing canopy. the sun. Portions of leaves and stems may • Control insect and disease problems Sunscald of bell pepper fruit. Cami Cannon, Utah State University Sunscald of tomato fruit. Howard F. Schwartz, Colorado State also scorch. Commonly seen on plants that (e.g. tomato hornworm, powdery University, Bugwood.org have lost foliage due to insect feeding or mildew) before they begin to defoliate disease. Affected fruits are inedible. plants. • Avoid cutting or breaking off leaves Disease Cycle: and vines during harvest (especially in • Occurs when temperatures are pepper, tomato, summer squash, and consistently above 90°F during the cucumbers). summer and fruits are exposed to • Trellis crops with heavy fruit load solar radiation. (tomato, pepper). • Construct shade cloth over the crop Time for Concern: When fruits are during the growing season. present and especially after loss of foliage • Select varieties noted to retain leaf due to insect feeding or disease. cover throughout the season, produce more foliage, and/or have a fruit When and Where to Scout: color that reflects more sunlight. • Monitor fruit for symptoms as it ripens. When to Consider Treatment: Sunscald of pepper fruit. Howard F. Schwartz, Colorado State Sunscald of bean pods. Howard F. Schwartz, Colorado State University, University, Bugwood.org Bugwood.org • Watch for openings in the leaf Since it is of a physiological nature, canopy, exposed fruits, and insect and prevention is key. disease damage that may defoliate or thin the leaf canopy. Look-alikes: mechanical damage restricting sap flow, internal fungal DISORDERS infections ABIOTIC ABIOTIC DISORDERS

Sunscald at the lower stem of recently transplanted Sunscald at the lower stem of recently transplanted pepper. Gerald Holmes, California Polytechnic State University at San Luis pepper. Gerald Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.org Obispo, Bugwood.org

162 163 Selected References Diseases Insect Pests A Checklist of Major Weeds and Crops as Natural Hosts for Plant Viruses in the Northeast. VEGETABLE CROPS. [accessed 2018 Feb 12]. http://vegetablemdonline.ppath.cornell.edu/ Cranshaw, W. 2004. The Ultimate Guide to Backyard Bugs: Garden Insects of North America. Tables/WeedHostTable.html New Jersey: Princeton University Press. American Phytopathological Society. Beet Curly Top: America’s First Serious Disease of Sugar Pacific Northwest Pest Management Handbooks. [accessed 2018 Feb 12]. https:// Beets. [accessed 2018 Feb 12]. http://www.apsnet.org/publications/apsnetfeatures/Pages/ pnwhandbooks.org/ CurlyTop.aspx

Seaman, Abby, Editor. (2016) Production Guide for Organic Carrots for Processing. Publisher: Utah Pests, Integrated Pest Management. Vegetable Diseases in Utah. [accessed 2018 Feb 12]. New York State Integrated Pest Management Program, Cornell University (New York State https://utahpests.usu.edu/ipm/agricultural/vegetable/diseases-utah Agricultural Experiment Station, Geneva, NY). Vegetable Diseases Cornell. [accessed 2018 Feb 12]. http://vegetablemdonline.ppath.cornell. Seaman, Abby, editor (2016). Production Guide for Organic Cole Crops. Publisher: New York edu/Tables/TableList.htm State Integrated Pest Management Program, Cornell University (New York State Agricultural Experiment Station, Geneva, NY).

Seaman, Abby, editor (2016). Production Guide for Organic Cucumber and Squash Crops. Publisher: New York State Integrated Pest Management Program, Cornell University (New York State Agricultural Experiment Station, Geneva, NY).

Seaman, Abby, editor (2015). Production Guide for Organic Peas for Processing. Publisher: New York State Integrated Pest Management Program, Cornell University (New York State Agricultural Experiment Station, Geneva, NY).

Seaman, Abby, editor (2016). Production Guide for Organic Potato Crops. Publisher: New York State Integrated Pest Management Program, Cornell University (New York State Agricultural Experiment Station, Geneva, NY).

Seaman, Abby, editor (2016). Production Guide for Organic Snap Beans. Publisher: New York State Integrated Pest Management Program, Cornell University (New York State Agricultural Experiment Station, Geneva, NY).

Seaman, Abby, editor (2016). Production Guide for Organic Spinach. Publisher: New York State Integrated Pest Management Program, Cornell University (New York State Agricultural Experiment Station, Geneva, NY).

Stop Brown Marmorated Stink Bug - StopBMSB.org. [accessed 2018 Feb 12]. http://www. stopbmsb.org/

Utah Vegetable Production & Pest Management Guide, USU. [accessed 2018 Feb 12]. https:// vegetableguide.usu.edu/index

Vegetable IPM Practices, New York State Integrated Pest Management. Vegetable IPM Practices. [accessed 2018 Feb 12]. https://nysipm.cornell.edu/agriculture/vegetables/ vegetable-ipm-practices mm 10 20

Rulers in Millimeters and Inches 30 40 50 60 70 80 90 100 120 30 13 inch 0 ¼ ½ ¾ 1 ¼ ½ ¾ 2 ¼ ½ ¾ 3 ¼ ½ ¾ 4 ¼ ¼ ¾ ¼ ¾ ¼ ¾ ¼ ¾ ¼ ½ ½ ½ ½ 10 20 30 40 50 60 70 80 90 100 120 13 0 0 1 2 3 4 mm inch discriminate regardingterms,privileges,orconditionsofemployment, against anyperson registered forediblecrops. “Restricted use” pesticidesmayonly beappliedby a licensedapplicator. Thepesticide applicatorislegally responsible forproper pesticides are labeledwith ingredients, andrisks,notallare instructions, June 30,1914, incooperation withthe U.S.DepartmentofAgriculture,Kenneth L.White, misapplication ofproducts orinformationmentionedinthisdocument.All use. USUmakes noendorsementoftheproducts listedinthispublication. otherwise qualified.Employeesandstudentsalsocannotdiscriminateinthe classroom, refuse tohire; discharge; promote; demote;terminate;discriminateincompensation; or because ofrace, color, religion,sex, nationalorigin,age,disability, orveteran’s status, publication isissuedinfurtherance ofCooperative Extensionwork,actsofMay8and discrimination onthe basisofsexual orientationinemployment andacademic related origin, age(40andolder),disability, andveteran’s status.USU’s policyalsoprohibits Utah State University is committed toprovidingUtah StateUniversity iscommitted anenvironment freefrom harassment and other formsofillegaldiscriminationbasedonrace, color, religion,sex, national not responsible fortheuse,misuse,ordamagecausedby applicationor Precautionary Statement: Utah State University anditsemployees are residence halls, or in on/off campus,USU-sponsoredeventsresidence halls, andactivities.This orinon/off practices anddecisions. UtahStateUniversity employeesandstudentscannot, Vice President forExtensionandAgriculture,UtahStateUniversity.