Diagnosing Horticultural Arthropod Pests and Injury Symptoms

Diane Alston Utah State University Extension Entomologist Distance Diagnostics in Utah Training October 18, 2007 Logan, UT Insect Diagnosis

Insect is present Injury is present What type of injury?

Friend or foe? Which life stage is present? Insect Feeding Types Borers Chewing Piercing-Sucking Aspen borer Mexican bean beetle Apple aphid

Cherry fruit fly Gall Formers Squash bug

Diagnosis Cooley spruce gall adelgid Scouting for Pests ◘ Look at the big picture ◘ Pattern of plant decline/injury ◘ Pest injury tends to be aggregated ◘ Can injury be associated with irrigation or other pattern? ◘ Look at new growth ◘ Check for root/crown problems ◘ Hand lens for small insects and mites ◘ Scout frequently

Raspberry horntail injury to cane tips Recognizing Common Insects Beetles Hard wing covering Most diverse group Strawberry root weevil Chewing mouthparts Cottonwood leaf beetle 7-spot ladybird beetle

White grub

Strawberry root weevil

Locust borer Ground beetle Ips bark beetle Prionus root borer

Larvae – grub-like Chewing mouthparts Beetle Injury

Trunks: Girdling in cambium & sapwood, tunnels, D-shaped exit holes girdling - Flatheaded borer

Tunnels through sapwood & heartwood, Round exit holes Skeletonizing - Japanese beetle –Roundheadedborer

Notching - Strawberry root weevil Distinctly Leaves: holes, skeletonizing, shaped notching galleries Prionus root borer under bark – Strawberry root weevil bark beetle

Roots/Crowns: tunnels, chew off fine roots Recognizing Common Insects Moths Colored scales on wings Adults feed on nectar Codling moth Good flyers Most are active at night

Peach twig borer

Greater Peachtree Borer

Cutworm/ Armyworm

Codling moth Larvae – caterpillars Chewing mouthparts Caterpillar Injury

Lilac Ash Borer Imported cabbage worm Tunnels in limbs and trunks

Forest tent caterpillar

Codling moth Holes chewed in leaves Tunnels and holes in fruits Recognizing Common Insects Hemiptera - True Bugs

Half wing: front is leathery, back is membranous Inverted triangle on back Piercing sucking mouthparts

Lygus bug

Big-eyed bug (predator) Stink bug nymph

Consperse stink bug

Squash bug Big-eyed bug nymph (predator)

Minute pirate bug (predator) Nymphs – mini adults without wings True Bug Injury

Boxelder bugs on pear Pitting and bumps: Cells killed when fruit is older

Toxin injected: Stink bug injury to peach Plant stunting and death Stink bug injury to Cat facing: apple Cells killed when fruit is young Recognizing Common Insects Aphid, Scale, Whitefly, Mealybug, Leafhopper Small Lecanium Soft bodied scale Soft, waxy or armored covering Pine needle Many produce honeydew scale Piercing sucking mouthparts

Many feed in phloem Striped mealybug Nymphs similar in Apple aphid appearance to adults

Green peach aphid Grape leafhopper Whitefly Aphid, Scale, Whitefly, and Mealybug, Leafhopper Injury Leaf curling Limb dieback

Apple aphid Leafhopper burn: Speckling

Leaf spots Honeydew is a food source from dead for sooty mold to grow cells Honeydew What is it? What is it? Who did it? What is it? Who did it? Who did it? What is it? What is it? Who did it? What is it? Who did it?