Date post: | 04-Jan-2016 |
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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”
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!