3/14/17 Insect Pests in the Landscape Key Tree and Shrub Insect • Ornamental Insect Pests Pests in the Landscape – Sucking Insects – Japanese Beetle – Boring Insects • Two-line Chestnut Borer • Bronzed Birch Borer Dr. R. Chris Williamson • EAB Department of Entomology • Linden Borer University of Wisconsin-Madison – Gypsy Moth – Fall Webworm – Viburnum Leaf Beetle Sucking Arthropod Pests Sucking Pests of Ornamental Plants • Most plant pests with sucking mouthparts belong to • Plant Bugs the insect order Hemiptera (True Bugs) • Lace Bugs – This group includes: aphids, cicadas, sXnk bugs, scale insects, • Aphids and Adelgids and their kin • Lea^oppers – ~80,000 species known! • Treehoppers • Spi_lebugs • Jumping Plant Lice (Psyllids) • Other plant pests with sucking mouthparts include • Scale Insects (Armored or So`) Thrips, whiteflies, mealybugs • Whiteflies and certain mites • Mealybugs • Thrips 1 3/14/17 IdenXfying Plant Bugs Plant Bugs: Four Lined Plant Bug • DisXnct Triangular Region • Pest on numerous annuals and present on wings perennials • Ex. azaleas, dogwood, maples, • This is disXnct to the family sumac Miridae (Plant Bugs) • Overwinter as eggs • Nymphs (red and black) emerge and feed in April/May • Adults (~1/4”; black and yellow) can be found in May/June • 1 generaXon per year Plant Bugs: Four Lined Plant Bug Plant Bugs: Ash Plant Bug • Pests of ash trees (what’s le`!) • Both nymphs and adults feed • Overwinter as eggs and can damage plants • Nymphs (reddish) emerge around leaf break • O`en cause dark spots on leaves (my resemble a disease); • Adults (~1/4”; black and yellow) can also cause curling of plant can be found in May through Xssues the growing season • 2 generaXons per year • May drop to ground and hide if disturbed Photos: James Solomon USDA; Whitney Cranshaw 2 3/14/17 Plant Bugs: Ash Plant Bug Plant Bugs: Honeylocust Plant Bug • Both nymphs and adults feed • Pest of honeylocust trees and can damage plants • Overwinter as eggs – First generaXon for the year is most damaging, as feeding occurs on • Nymphs (yellowish-green) young leaves emerge around leajreak • Adults (~1/4”; greenish) can be • Cause a yellow, mo_led found in June appearance on leaf surfaces – Young leaves can appear wilted • 1 generaXons per year; populaXons decline in late June/ Nymph Adult July Photos: Jeff Hahn, UMN Entomology Dept.; James Solomon USDA Plant Bugs: Honeylocust Plant Bug Lace Bugs • Several species in the Midwest • Cause mo_ling and distorXon of leaves; young leaves may be • Numerous hosts: azaleas, oak, elm, curled (can resemble herbicide damage) birch, crabapple, linden, aspens, • Prefer yellow varieXes of honeylocust (‘Sunburst’) over green willows, roses, and others varieXes (‘Shademaster’ or ‘Skyline’) • White or black colored; wings pa_erned with ornate, lace-like pa_ern; adults ~1/8-1/4” • Typically overwinter as adults (and some eggs); mulXple generaXons per year; can be found into the fall Immatures Adults 3 3/14/17 Lace Bugs Lea^oppers • Can cause yellowing (chlorosis) • Wide variety of plants are or sXppling of leaf Xssue a_acked by lea^oppers – Damage can appear similar to • Can cause stunted growth; that of spider mites browning, and curling of leaves (“Hopper Burn”) • Lace bugs found on underside of leaves • Can carry and transmit plant diseases • Plant damage can be sever if diseases have been transmi_ed! Hopper Burn on Apple Treehoppers Management of Sucking Insects (excluding scale insects) • IdenXfiable by crest on top of head • Wide variety of insecXcides available to manage Sucking pests • RelaXvely minor pests of ornamentals • Check the label to make sure a product meets usage requirements Insects Type of Insec8cide Examples of Ac8ve Ingredients • Damage to foliage is usually superficial/cosmeXc Organophosphates Acephate, chlorpyrifos* • Can damage while laying eggs (oviposiXon scars) Plant Bugs Lace Bugs Chinch Bug Carbamates Carbaryl Aphids Adelgids Pyrethroids Bifenthrin, cyfluthrin, fluvalinate, Lea^oppers deltamethrin, permethrin, pyrethrin Treehoppers Spi_lebugs NeonicoXnoids Clothianidin, dinotefuran, imidacloprid, Psyllids thiamethoxam Whiteflies Mealybugs Other InsecXcidal soaps, horXcultural oils, OviposiXon Scars Buffalo Treehopper Thrips azadirachXn 4 3/14/17 Management of Sucking Insects (excluding scale insects) Scale Insect Pests • Some of the aforemenXoned insect pests cause • Two Types: Armored (i.e., Hard) and So` Scales superficial/cosmeXc damage • > 60 species in Midwest (see Dr. Cliff Sadof’s website) • May be able to avoid pesXcide use • Damage plant by sucking plant juices • Ex. If few galls are present, prune (remove) them • RelaXvely immobile, only move as crawlers in summer Armored vs. So` Scales Scale Feeding Pa_erns: Leaf Cross SecXon: Armored Scales So@ Scales Protec8on Hard/Armored protecXve No true armor, protected coaXng; can be removed by waxy secreXon; protecXon can NOT be removed Length of Mouthparts Long piercing mouthpart Short piercing mouthpart Feeding Loca8on Mesophyll feeders Phloem feeders Forma8on of honeydew No honeydew formaXon Excrete honeydew Overwintering Stage Usually eggs Usually nymphs Soft Reproduc8ve Capacity Females produce ~100 Females produce ~1,000 eggs (less dynamic) eggs (more dynamic) Armored Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates 5 3/14/17 Scales encrust branches and/or leaves; cause Armored Scale Insects dieback and death of plant Armored Scales Form a “Shell-like” Cover from Shed Skins and Waxy SecreXons Covers flipped (removed) to reveal scale insects 6 3/14/17 Common Armored Scale Insects • Obscure Scale • Oystershell Scale • Pine Needle Scale • Euonymus Scale • Juniper Scale Close-up of Armored Scale Insect Obscure Scale • Major pest of pin oaks • Encrusts limbs, branches • Causes stress, die-back, tree decline, and even tree death Thinning, Dieback from Obscure Scale 7 3/14/17 Oystershell Scale Pine Needle Scale A_acks lilac, maple, willow, ash, poplar, apple, hawthorn, dogwood, others Euonymus Scales: Males (White) and Euonymus Scale Females (Gray) 8 3/14/17 Males Mostly Infest Leaves Chlorosis due to feeding Dieback from Euonymus Scale Japanese Beetle Biology • Adults emerge in mid-June through early- September • Adults are gregarious, sun-loving animals • Adults are skeletonizers, NOT defoliators • Adults feed on leaves, flowers and fruit • Attack >350 species • ONE year life cycle 9 3/14/17 Japanese Beetle Life Stages – egg 1st 2nd 3rd pupa adult instar larva 10 3/14/17 Management Systemic InsecXcides • Systemic Insecticides: Soil drench or injection • Acetamaprid (Tristar) • Trans-laminar products applied to foliage prior to • Clothianidin (Arena) or during adult activity (after flowering!) • Dinotefuran (Safari) • Contact insecticides applied directly to active adults (under sunny conditions in upper canopy, • Imidacloprid (Merit)* after flowering)- Avoid applications to flowering • Thiamethoxam (Meridian) plants! • Acephate (Lepitect)-Orthene – Imidacloprid can not be applied to basswood or linden species! – Imidacloprid can not be applied to basswood or linden species! 11 3/14/17 Trans-laminar InsecXcides Contact InsecXcides • Acetamaprid (Tristar) • SyntheXc Pyrethroids • Clothianidin (Arena) – Bifenthrin (Talstar) • Dinotefuran (Safari) – Beta-cyfluthrin (Tempo) – • Imidacloprid (Merit)* Deltamethrin (Deltaguard) – Lambda-cyhalothrin (Scimitar) • Thiamethoxam (Meridian) • Carbaryl (Sevin) – Imidacloprid can not be applied to basswood or linden species! • Chlorantraniliprole (Acelepryn) • Permethrin (Astro) Two-lined Chestnut Borer Two-Lined Chestnut Borer • Native species • Coleoptera: Family Buprestidae • Adult = Metallic Wood Borer • Larva = Flat Headed Borer • Hosts – Oak and Chestnut, stressed trees are most susceptible • Life Cycle = ONE year, sometimes two years in northern climates and poor trees 12 3/14/17 DAMAGE • Injury symptoms caused by girdling first appears as limb dieback and thinning of crown, similarly to Bronze birch borer • Adults create D-shaped exit holes BIOLOGY MANAGEMENT • Adults emerge in June – mid-Sept. • Systemic insecticide applications preceding fall are effective as preventative treatments, NOT • Adults are sun-loving curative! • Eggs are laid in crack and crevices in the – Imidacloprid (Merit) trunk bark, usually in sections exposed to – Chlothianidin (Arena) – Thiamethoxam (Meridian) sunlight • Bark spray applications made once adult Two- • Larvae primarily tunnel in cambium layer lined Chestnut Borer adults are active (i.e., late- under bark May –June) – Permethrin (Astro) • ONE generation per year, sometimes – Bifenthrin (Onyx) requires two years in northern climates! – Chlorpyrifos (nursery ONLY) 13 3/14/17 Bronze Birch Borer Bronzed Birch Borer • Native species • Coleoptera: Family Buprestidae • Adult = Metallic Wood Borer • Larva = Flat Headed Borer • Hosts – European white birch, especially stressed trees • Life Cycle = ONE year, sometimes two year in northern climates DAMAGE • Initial damage symptoms appear as crown dieback • Larvae feed mainly in cambial area creating callused girdling that spirals around the bark • Adults create D-shaped exit holes 14 3/14/17 BIOLOGY • Adults emerge in late-May – June • Adults lay most eggs in the upper crown on branches < 1 inch diameter • Stressed trees are more susceptible • Larvae tunnel in cambium layer under bark, rarely moving into xylem • ONE generation per year, sometimes requires two years in northern climates! MANAGEMENT • Systemic insecticide applications preceding fall are effective as preventative