Defoliators Continued: Gypsy Moth and Sawflies

The gypsy moth: Lymantria dispar L.

A world class problem: another Lymantriidae

The Gypsy Moth, Lymantria dispar L.

• Gypsy moths are native to north Africa, all across eastern and western Europe, across Siberia, the Russian Far East and on into Japan. What an enormous range?

• With this enormous gene poolenormous gene pool, it’s small wonder that gypsy moths consume the foliage of practically any hardwood.

Gypsy moth biology, ecology and control has been studied for a long time, especially in Europe.

An opening statement: A single instance of complete defoliation can kill conifers, i.e. white pine, and eastern red pine.

Three consecutive defoliations kill deciduous trees, especially the oaks.

Defoliation of eastern oak white pine forests by the gypsymoth – heavy oak mortality.

• The pest was brought into the U.S. by an artist, amateur astronomer and biologist, Leopold Trouvelot.

• Trouvelot lived at 27 Myrtle St. in Medford, Mass. He wished to cross the gypsy moth with the satin moth and start a silk industry in the U.S.

• In 1889 some moths escaped, and the rest is history!

American Naturalist. 1867.Vol.1, pp. 30-38

Etienne Leopold Trouvelot and his house on 27 Myrtle St., Medford, MA. His gypsy moths escaped in 1889.

Medford Fire Departmentcutting and burningdead oak trees.

Medford, MA courthouseand its famous oak trees,and they are dead.

The first demonstrationof the power of the “GypsyMoth.”

20 yrs later!

Spread fast across the U.S.

Spread: Eggs are laid on anything, including cars, campers, outdoor furniture, tent folds etc.

If the larvae don’t land on their hosts, they can easily land on air cargo containers, trains, ships, buses etc. Not called gypsy moth for nothing!

Asian gypsy moth eggs on military equipment comingfrom Germany to Ft. Benning, Georgia

The entire U.S. is continually monitored for the gypsy moth. Often one pheromone trap/4 sq. mi. along highways & a trap/1 sq. mi. in population centers.

Active gypsy mothtacking system inCanada also.

Egg laying sites search

Opened pheromonetrap

Pheromone trapsat hwy. rest stops

Objects aroundold barns searchedfor egg masses

When males are trapped the affected area is delimited: 1st. 4 traps/sq.mi., then 8 traps and even 16 traps/sq.mi.

When the source is found:

The area (often a backyard) is treated with one or two Bt sprays.

When egg massesare found, threesprays of Bt bracket the emergence of the moths.

Life cycle of thegypsy moth

Lifecycle of thegypsy moth

Over the years many parasitoids and predatorshave been introduced from Europe to control thegypsy moth, only a few have become established.

The Calosomaground beetleis a good example.

The best natural control, however, is the

Wipfelkrankheit that somehow was introduced from Germany in 1909.

Even though the gypsy moth is an exotic pest itsmain natural control did enter North America. It’s a NPV virus called (in English) the wilt disease.

The NPV particles enters the larvae where the virus kills the insectan blood cells and the larvae seem to wilt.

Gypsy mothpopulation

Weather

Hosts

Site - soil - climate Competition

- intra - inter

Health ofthe population

Virusepizootic

Naturalenemies

Directinsolation

Big current problem is the potential establishment of the Asian variety of the gypsy moth.

Asian European

And she flies!

The two varieties of the gypsy moth

1992 Eradicationprogram against the Asian gypsymoth

The Sawflies: ImportantDefoliators of Hardwoodsand Conifers.

Some Are Leafminers,Skeltonizers, but MostAre Leaf-chewers.

Sawfly defoliators are larvae of a group of primitivewasps, the Symphyta.

Sawfly larvae look like caterpillars, but they aren’t.

Caterpillars are Lepidoptera

Sawflies Caterpillars

More Sawflies

Oviposition of sawfliesinto pine needles

Sawfly larvae feedingon conifer foliage.

Feed in spring!

Feed in summer!

Sawfly defoliationof hybrid poplar plantation nearPortland, OR.

Poplar sawflypupa, new adult ovipositing andlarvae devouring the foliage.

Adult in spring

Sawfly larvae

Number of eggs per female = 63.74

Larval parasitoid

Pupal parasitoid

My 1958 experience withthe black-headed sawflyin East Texas.

1958 outbreak of the black-headed sawfly, Neodiprionexictans.

2,400 Acres

(1) Raining frassand the foliageis thinning.

(2) Aerial appraisal

Swamp

Kirby Lmbr. Co.R.R. Skidway

D4

D4

Cocoons

The great 1958spraying operationdirected by Bob G.

Loading DDT

The Kirby skidwayused as runway

Headquarters and radio

Spray planes liningup on smoke

Smoke

Even though defoliators are beautifulwe must move on to Barkbeetles