Sucking and Gall Forming Insects

Sucking and Gall-Forming Insects

Sucking Insects • Mouthparts pierce plant tissue and draw out fluid • Importance: – Usually low in forests – Overuse of pesticides can incite damaging infestations – Some deadly exotics in U.S. – Some vector plant disease

• Often favor young succulent growth, high in nitrogen

Sucking insects: wide diversity Scales

Lacebugs

Adelgids

Mealybugs

Thrips

Spittlebugs

Thrips

Aphids

Whiteflies

Tree/leaf- hoppers

Sucking Insects: possible signs and symptoms Honeydew

sooty mold

Ants

Sucking Insects: possible signs and symptoms Wooly ash aphid

Curled, discolored, and/or distorted foliage Pink hibiscus mealybug

Thrips “stippling” on sweetgum

Sucking Insects: possible signs and symptoms Waxy or cottony masses or coatings

Woolly pine scale Asian wooly hackberry aphid Flatid planthopper excretion

Pine bark adelgid

Sucking Insects: possible signs and symptoms Twig and branch dieback Kermes scale

Aphids

Asian Wooly Hackberry Aphid

Oleander Aphid

Crapemyrtle Aphid

Giant Bark Aphid

Scales

Tuliptree scale

Scale “crawler”

Oak Lecanium Scale

Florida Wax Scale

Holly Pit Scale

Pine Needle Scale

Sycamore Lace Bug

Damaging Exotic Sucking Insects in Florida Pick Hibiscus Mealybug

Lobate Lac Scale

Hemlock Woolly Adelgid An exotic eliminating eastern hemlocks

Factors that influence occurrence & impact: sucking insects • Young succulent tissue • Enhanced nutrient levels • Overuse of broad-spectrum insecticides

Management: sucking insects • Do nothing (let natural enemies do the job) • Inspect for evidence of ladybugs, lacewings, other natural enemies • Hard jet of water (periodic, safe on natural enemies) • Insecticidal Soaps (e.g., Safer’s, M-Pede,homemade) – Disrupts cuticle, must cover pest, target scale crawlers

• Horticultural oils (e.g., SunSpray Ultra-fine oil) – Act by suffocation, must cover pest, target scale crawlers

• Systemic Insecticides (e.g. Imidacloprid) – as root drench, trunk injection

Galls • Abnormal plant cell growth stimulated by another organism – wasps, midges, aphids & mites – Bacteria, fungi, nematodes

• >2000 gall producing-insects in the United States – 60% occur on the oak family

• Primarily of aesthetic concern • Stem galls may kill shoot

Oak Apple Gall • Spherical galls on oaks in spring, summer • Alternating wasp generations – Adults emerge from galls, mate, female lays eggs in roots – Female wasps emerge from roots in 2nd spring, lay egg in leaf midrib

Amphibolips confluenta

Horned Oak Gall • Caused by cynipid wasps – Callirhytis spp.

• Laurel, water, other oaks • Alternating twig and leaf gall stages • Dense laurel oaks on poor sites

One wasp emerges from each “horn”

Cypress Twig Gall Midge • Spongy galls on ends of new cypress growth • Orange larvae inside, overwinter • Galls drops with foliage in winter

Management: galls • Appreciate the beauty • Prune and destroy galls containing active life stages • Plant site-appropriate tree species • Conserve natural enemies through limited pesticide use

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