264 APPLIED ENTOMOLOGY 



trunks and limbs of the trees, but others are found in cavities in the trunks, on 

 the stones of stone walls, even in the middle of the wall, in tin cans, and in fact, 

 anywhere the female may crawl to. They hatch the following spring. 



Distribution appears to be accomplished by the crawling of the caterpillars; 

 by carrying to other places objects on which egg-clusters have been deposited; 

 by caterpillars spinning down on threads from the trees onto passing vehicles; 

 and by the wind. 



The injury caused by this insect is often very serious. The caterpillars 

 have voracious appetites and eat large amounts and their abundance has often 

 resulted in the stripping of large areas, which repeated several years in succession 

 usually causes the death of the trees. With evergreens, a single defoliation is 

 usually sufficient to kill the trees, and in many parts of Eastern Massachusetts 

 the thinning of woodland areas in consequence of the work of these insects, is 

 very evident. 



Parasites and other enemies of the Gypsy Moth have been introduced in 

 large numbers by the Federal Government, and where these have become abun- 

 dant they have done good work, though of course nothing like extermination of 

 the pest has been accomplished. A wilt disease present in favorable seasons, 

 kills many of the larvse at such times. In general though, outbreaks of this 

 insect in any locality are not repressed by their natural enemies for several years, 

 and in the meantime the damage is great. This condition therefore calls for 

 the use of control methods. 



Control. — The egg clusters constitute one place where control measures can 

 be applied. It is much easier to kill 400 or 500 insects concentrated in a space 

 an inch square or less, than the same number in the larval stage, scattered over 

 a tree. Soaking the egg clusters at any time after they are laid until they hatch 

 the following spring, with creosote to which a little lampblack has been added 

 (to show by its color which clusters have been treated and which have not) is a 

 good treatment. Care must be taken, however, in using this material, to take 

 enough to reach all the eggs in the cluster. Usually a swab on the end of a 

 stick, soaked in the creosote, is used for this work. The difficulty with this 

 method is that of finding all the egg clusters in their varied places of concealment. 



While the caterpillars are very small, spraying infested trees and other 

 plants with arsenate of lead, using about 5 lb. of the paste (23^ lb. of the powder) 

 in 50 gal. of water, is a good treatment, but as the larvse become larger they 

 seem to develop a greater resistance to poisons and spraying becomes less 

 effective. 



As the larvse feed largely at night and seek concealment during the day, put 

 loose bands of burlap around the trunks of infested trees, where they may hide 

 in the daytime. Success with this method of control is dependent upon daily 

 visits to the bands and the destruction of the caterpillars found under them. 



Sticky bands around the trunks of non-infested trees will keep the caterpillars 

 off such trees as long as the bands remain fresh and in good order. 



As the caterpillars do not feed on the pine until after they have passed their 

 second instar, pure stands of pine may be protected by removing all under- 

 growth other than pine and banding the trees as above, to prevent older larvse 

 from crawling to them from places outside where they have obtained their earUer 

 food. 



