498 ANNUAL. REPORTS OF DEPARTMENT OF AGRICULTURE. 



The brown-tail moth has established itself in the northeastern 

 part of the State in several towns. A line from Providence to 

 Springfield, Mass., would include practically the area infested. 



GENEBAL CONDITIONS. 



The force of men on the pay roll has varied from 170 to 540. As 

 the roadside work is carried from the cities into the farming districts 

 we have been able to get men for the work who are more accustomed 

 to hard outdoor labor, and the efficiency of the force is constantly 

 increasing. 



During the feeding season of the caterpillars, 10 gasoline-power 

 spra3dng machines w^ere used, and approximately 40 tons of arsenate 

 of lead have been distributed. 



The inspection of forest products shipped from the infested terri- 

 tory to points around its outer border has been continued, and Christ- 

 mas trees and wreaths for holiday decoration have been added to 

 the list of material which the transportation companies will not ac- 

 cept without inspection certificates or permits. 



A most important series of experiments has been carried on with 

 regard to the relative resistance of native trees to the attack of the 

 gi})sy moth. All publications upon the feeding habits of the gipsy 

 moth caterpillar state that the food plants include almost our entire 

 native llora. Although it has long been known that this insect has its 

 favorite food plants, very few trees have been considered as immune 

 or even resistant. It now transpires that a number of species of trees 

 are resistant if in clean stands, or in mixed stands when all the trees 

 are of the varieties considered resistant. An experiment, for example, 

 has been made on a 17-acre tract of chestnut, the owners of which 

 granted permission for the removal of all trees except those thought 

 to be resistant. The tract was badly infested with egg clusters, which 

 were left untreated. The trees have not been sprayed, and only a 

 few along the roadside have been banded. The underbrush was 

 removed, together with all the oaks and birches. There are now no 

 trees standing on the ground except the chestnuts and a few white 

 pines. The result was that the foliage continued practically perfect. 



On another experimental tract in the town of Methuen the pines, 

 hemlocks, and maples only were left. The egg masses were not creo- 

 soted except on a few trees. The trees on a strip 200 feet wide were 

 banded where this lot adjoins another infested but untreated wood 

 lot. No spraying has been done and no other attention given except 

 to keep the few bands in a perfect condition. The foliage on this 

 tract remained nearly perfect, whereas many of these trees would 

 have suffered severely if the faA'orite food trees had been left growing, 

 since when the foliage of the latter w^as consumed the others would 

 have been attacked by the well-grown caterpillars. It seems that the 

 trees most subject to attacks of the gipsy moth, the removal of which 

 is advised wherever possible, are the neglected apple trees, the oaks, 

 the birches, and the willows. The same species are favorite food 

 trees for the caterpillars of the brown-tail moth. 



The reason for the success of this new method seems to be that 

 the young caterpillars of the gipsy moth are able to feed only upon 

 the foliage of the favorite plants, and that when the eggs happen to 

 have been placed upon one of the resistant species they are unable to 



