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 Spittlebugs Thrips Mealybugs Thrips Tree/leaf- hoppers Aphids Whiteflies

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 Crapemyrtle Aphid Asian Wooly Hackberry Aphid Oleander Aphid Giant Bark Aphid

Scales Tuliptree scale Scale “crawler” Oak Lecanium Scale Holly Pit Scale Florida Wax 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 Laurel, water, other oaks One wasp emerges from each “horn” 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

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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