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&section=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