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EXTENSION EXPERTS MONITORING GYPSY MOTH SPREAD

AUBURN, APRIL 14, 2000---The gypsy moth that escaped into the forests of Massachusetts about 130 years ago has made its way into Alabama. 

Dr. Wayne Brewer, an Extension entomologist, is confident the moths eventually will gain a toehold in Alabama.  In the meantime, funding from the U.S. Department of Agriculture’s Animal Plant and Health Inspection Service  and additional support from Extension System agents is helping set traps in 45 counties north of Montgomery to  detect this unwelcome pest. 

The gypsy moth is one of the most devastating pests of forest trees in the United States. Caterpillars feed on the foliage of hundreds of plant species, although the most common hosts are oaks and aspens. When moth  populations are high, trees may become completely defoliated, Brewer says. Several years of defoliation, coupled with other stresses caused from drought and other factors, kills many trees. (In picture above, Extension entomologist Wayne Brewer inspects one of many traps that will be set to help monitor for traces of the gypsy moths.  Click picture for a larger version of the image)

While tree death can be heavy at times, experience with infested forests in the northeastern United States shows less than 20 percent of trees are lost.

In 1868, the gypsy moth was brought into the United States from Europe by Leopold Trouvelot, a Frenchman hoping to develop an improved strain of silkworm. 

Unfortunately, in the course of his experiments, some of the moths escaped. 

"As the story goes, Trouvelot warned the city fathers about the escapes," Brewer says, "but nothing was done until almost 10 years later when the problem had become apparent.

New England paid dearly for this oversight. Not long after Trouvelot’s return to France, the moths wreaked havoc in the area and spread throughout the Northeast. 

"Generally, a few moths move into the area, their population increases dramatically and defoliation occurs -- much to the dismay of property owners," Brewer says. 

What often results is a change in the forest’s composition. In urban and suburban landscapes, valuable landscape trees may be lost. In highly populated areas the moths create a nuisance because larval feeding results in excrement dropping on decks, picnic tables and people. Also, larval hairs, while not poisonous themselves, cause allergic reactions among some people. 

Although moths feed on pines and other conifers, their survival rate on these trees aren't as high as on hardwoods. For this reason, Brewer says, the moth won't be a problem in the southern part of the state where conifers are prevalent.

The moths already have spread west to Wisconsin and south to North Carolina. Occasional traces of the insect 
have turned up in north Alabama. 

Ironically, people are the biggest contributor to the moth’s spread. Brewer describes the moth as a hitchhiker. Female moths lay their eggs on any vertical surface, usually trees. However, camper trailers and other recreational vehicles do just as well. As a result, when people from northern-infested areas travel south for vacation, they bring the eggs with them, Brewer says. The eggs hatch and move to nearby trees to feed.

Brewer is confident that moth populations will increase in Alabama. So far, only a few moths have been trapped in Alabama -- most likely brought in on vehicles from the North. When a moth population is located in Alabama, Brewer says he and other experts will make every effort to eradicate it before it spreads.

The good news is there are a number of insecticides and biological methods available to control the moths. For example, a virus specific to the moth has been cultured and used as a viral spray in northeastern forests. Another promising agent is a fungus that, when used under the right conditions, kills many moths. 

In addition, fire ants, small mammals and birds are major predators of the moths, which may account for moths not gaining a toehold in the Deep South, Brewer says. 

Nevertheless, Brewer believes this will not be enough to stop the moth’s onslaught. 

"It’s possible the moths will continue to move and become established here over a long period of time," he says. "Another scenario is that the insects will be accidentally introduced into and established in an area that no one notices. Hopefully, our efforts will prevent that from happening."

SOURCE: WAYNE BREWER, Extension Entomologist, Alabama Cooperative Extension System, 
(334) 844-2935