Scale DiseaseMaggie JordanDecember 7th, 2011
Overview
Define Scale
Look at two main categories
Define and associate damage
Look at a few types
Describe methods of treatment
Scale
Appears as small bumps on trees and shrubs
Scales are actually insects
Parasites that suck out plant juices
Male’s only purpose in life is to feed. They have no functional mouthparts and cant feed. Males disappear after mating (of course)
Scale Life Cycle
Greatly vary between species
Eggs are laid beneath ovisacs
Generally hatch in 1-3 weeks
Many species of males grow wings and fly to locate mates
Spends most of life feeding on same spot of a plant
secrete a waxy material that covers and protects them from predators, drying out and contact insecticides
Crawlers
Newly hatched nymphs
Crawlers small and flattened, look like dust
Six legs move around plant until they find suitable feeding site them molt and begin forming scale over their bodies
Susceptible to insecticide sprays
Infestations spread when crawlers walk or are blown by the wind to nearby plants or plant parts
Crawlers for Euonymus Scale
Two Major Categories
Those that excrete a sugary liquid (honeydew)- SOFT
Those that do not- HARD
Honeydew DamageExcrete a sugary liquid
Threat to plant health
The sugary liquid attracts ants, flies and wasps
http://www.youtube.com/watch?v=SMVF40Mcrx4&feature=related
Liquid becomes a food for a black air-borne fungus called sooty mold
Sooty mold can effect photosynthesis by shading leaves and reducing plant growth
Honeydew also causes damages to streets, bikes, benches, etc.
Sooty Mold Damage
Other Damage
Scales feed on contents of plant cell
“The armored scale's straw-like mouth moves like a plumber’s snake to burst plant cells and feed on their contents” –Purdue Entomology
Large numbers weaken plant and can kill it
Becomes prone to drought, severe temperatures and other insect attack
Some species inject a toxin into a plant as they feed and cause even more damage
Soft ScaleGenerally one generation per year
appear convex in shape or resemble a helmet
highly active crawlers
Secrete attached, thin, waxy layer that can’t be separated from bodies
Move between branches and leaves and produce sticky, shiny, wet-looking honeydew.
With a heavy population, sooty mold can form
Crawlers hatch from eggs in mid summer and usually crawl directly to leaves then excrete honeydew then return to twigs and bark
Females can have up to 1,000 eggs
Eighty-five species of soft scales occur in the United States, with 60 species in Florida.
Hard Scale
use shed skins and wax that is unattached to their body to form hard, shell like cover. Do not move to leaves
generally, two or more generations per year
appear circular or rounded in shape
crawlers are less active compared to soft scale crawlers
rupture and destroy plant cells they are feeding on and oftentimes bypass the plant vascular bundles that transport nutrients through the plant
Armored ScalesThree hundred-fifty species of armored scales occur in the United States and about 175 species are present in Florida.
Armored Scalessucking insects, feeding on the contents of cells
not as easily killed with systemic insecticides as are soft scales that feed on phloem contents
many systemic insecticide labels list armored scales as being suppressed rather than controlled
Winged males crawl out from below clear wax shell and mate with still covered females
Females can produce about 100 eggs each
Kiwi fruit- http://www.youtube.com/watch?feature=endscreen&NR=1&v=395XmUkWVBg
Some Types….
Soft
Gum-tree scale
Brown Soft Scale
Hemispherical Scale
Hard
Pine Needle scale
Oystershell scale
Euonymous scale
Soft scales
Cottony maple scale (Pulvinaria innumerabilis)European elm scale (Gossyparia spuria)
Fletchers scale (Parthenolecanium fletcheri)
Magnolia scale (Neolecanium cornuparvum)
Pine tortoise scale (Toumeyella parvicornus)
Tuliptree scale (Toumeyella liriodendrii)
Spruce bud scale (Physokermes piceae)
Hard scales
Hemlock scale (Abragallaspis ithacae)
Obscure scale (Melanaspis obscura)
Oystershell scale (Lepidosaphes ulmi)
San Jose scale (Quadraspidiatus perniciousus)
Euonymus scale (Unaspis euonymi)
Pine needle scale (Chionaspis pinifoliae)
Scurfy scale (Chionaspis furfura)
Juniper scale (Carulaspis juniperi)
Gum-tree scale
Brown Soft Scale
Hemispherical Scale
Pine Needle Scale
Oystershell Scale
Euonymus Scale
Mealy Bug
http://www.youtube.com/watch?NR=1&feature=endscreen&v=rmUSz-56yD0
Treatment/Management
Build up to large numbers before they’re noticed
Hard to control because of scale protection
Crawlers most vulnerable
Sprays/Insecticides
Dormant oils
Adhesive bands
Predators
Birds such as the silvereye feed on insects
Frogs and possums feed on honeydew and destroy scale in process
Insect predators- assassin bugs, lacewings, hoverflies, ladybird beetles and caterpillars, several wasp and fly species
Attacked also by insect-attacking fungi
Expected Learning Outcomes
Look at ecological problem and relate it to:Parasitic relationship
Biodiversity
Life cycle
Predation
Environmental impact/damage
Works CitedPurdue pest information- http://extension.entm.purdue.edu/eseries3/view.php?article=articles/scale_insects_on_shade_trees_and_shrubs.txt&id=1§ion=Landscape%20and%20Ornamentals
http://bugs.osu.edu/bugdoc/Shetlar/factsheet/ornamental/FSscaleuonymus.htm
University of Illinois Home, Yard and Garden Newsletter- http://hyg.ipm.illinois.edu/article.php?id=154
South Australia Forestry-http://outernode.pir.sa.gov.au/forestry/publications_index/forest_health_information/factSheets/gum-tree_scale
Pictures: heyne.com.au, flickrhivemind.net, outernode.pir.sa.gov.au
University of Florida-edis.ifas.ufl.edu/mg005
Washington State- treesforyou.org/Planting/insectsandDisease/insects/scale_insects.htm
Meyers Pest Services- blog.myerspest.com
http://www.floridiannature.com/GardenPests.htm
http://ipm.illinois.edu/landturf/insects/oystershell_scale/index.html