510 ANNUAL REPORTS OF DEPARTATENT OF AGRICULTURE. 



FIELD WORK AGAINST THE GIPSY MOTH AND THE BROWN-TAIL MOTH. 



The work against the gipsy moth and the brown-tail moth during 

 the fiscal year ending June 30, 1910, has been continued along lines 

 similar to those used in previous years, with a few modifications and 

 additions. The infested area is somewhat hirger, but the rate of in- 

 crease is proportionately less than it has been in any year since the 

 beginning of the work. Except for the finding of a bad colony of the 

 gipsy moth at Wallingford, Conn., all the additions to the territory 

 have been contiguous to the previouslj^ infested areas. The coopera- 

 tion with the state authorities in the infested States has been most 

 cordial and effective, and the livable conditions in the older infested 

 areas are better than at any previous period since 1900. This means 

 that the streets, roadsides, and cultivated lands are measurably free 

 from both pests. Spread has been in forested areas, and looking 

 away from the roadsides toward forested hillsides it was possible at 

 any period during July to find large ranges of browned trees indi- 

 cating the almost total removal of the foliage. As indicated before, 

 however, the death of forest trees does not necessarily follow a com- 

 plete defoliation in July, since the coming of rains in August brings 

 out another crop of leaves, thus saving the trees from asphyxiation. 

 Moreover, it is becoming evident that it is only rarely that the same 

 area is completely defoliated two years in succession. It much more 

 commonly occurs that the bulk of the caterpillars in a large infesta- 

 tion bringing about complete defoliation die as the result of disease 

 from overcrowding, or from starvation owing to the complete de- 

 struction of food; hence the following season the new infestation 

 begins on the borders of the old one, and contiguous rather than 

 identical areas are defoliated. 



The work, as in the past, has been confined chiefly to the gipsy 

 moth. The infested area in New England is now little more than 

 10,500 square miles. 



There has been little increase in the area infested by the brown-tail 

 moth within the past year. The territory which this insect is now 

 known to inhabit is about one-third of the extent of New England. 



WOKK IN MASSACHUSETTS. 



The work in Massachusetts has been principally in the way of 

 keeping the most traveled woodland roadsides through the worst- 

 infested areas clear of the gipsy moth, and has been a continuation 

 of previous work in nearly every direction, except south, where the 

 conditions are not so serious as they are north and west of Boston. 

 The roadsides which have been cared for more than one year are in 

 such condition as to require a constantly lessening annual expense, 

 and in a few instances additional work may be discontinued, since the 

 roads are so clear that the towns are willing to care for them them- 

 selves. It seems that the Bureau may be able to induce the towns to 

 take over more of the work which it has been caring for. As shown 

 in previous reports, the strip on either side of the road which has 

 been cleaned up has been 100 feet in width. Experimentally during 

 the past year in several instances this width has been reduced to 75 

 and 50 feet. If these narrower belts prove to be effective in keeping 

 the caterpillars from roadways, an extension of the number of miles 

 of roadsides covered can be gained with the same appropriation. 



