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

Thrips

Mealybugs

Aphids

Lacebugs

Thrips

Whiteflies

Adelgids

Spittlebugs

Tree/leaf- hoppers

Sucking Insects: possible signs and symptoms

Honeydew

sooty mold

Ants

Sucking Insects: possible signs and symptoms

Curled, discolored, and/or distorted foliage

Pink hibiscus mealybug

Wooly ash aphid

Thrips “stippling” on sweetgum

Sucking Insects: possible signs and symptoms

Waxy or cottony masses or coatings

Asian wooly hackberry aphid

Flatid planthopper excretion

Woolly pine scale

Pine bark adelgid

Sucking Insects: possible signs and symptoms

Twig and branch dieback

Kermes scale

Asian Wooly Hackberry Aphid

Giant Bark AphidOleander Aphid

Aphids

Crapemyrtle Aphid

Scales

Oak Lecanium Scale

Florida Wax Scale

Holly Pit Scale

Pine Needle Scale

Tuliptree scale

Scale “crawler”

Sycamore Lace Bug

Damaging Exotic Sucking Insects in Florida

Lobate Lac Scale

Pick Hibiscus Mealybug

Hemlock Woolly AdelgidAn 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

• 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

Oak Apple Gall

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

Thanks Again!