BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 27 
defoliation in the eastern part of the infested area than had been recorded in 
the several years immediately preceding. This was particularly true as to 
Barnstable and Plymouth Counties in Massachusetts. Beyond these sections 
the amount of defoliation increased considerably, particularly in New Hamp- 
shire, westward to the Connecticut River, and in Massachusetts from the cen- 
tral part of Worcester County to and beyond the above-named river. The 
records for the summer of 1934 showed that there was considerable increase 
in defoliation for Maine and New Hampshire. Massachusetts showed some 
decrease, owing principally to a decided decrease in the southeastern part of 
the State, which was not offset by a large increase farther west. There 
was a decided increase in the amount of defoliation in Rhode Island. 
EFFECT OF DEFOLIATION ON FOREST GROWTH 
Beginning about the middle of January 1935 an extended series of observa- 
tions on the extent of gypsy moth infestation and damage caused to woodland 
was begun in several towns in the eastern part of Franklin County and the 
northwestern part of Worcester County, Mass. The purpose was to obtain 
accurate records of the degree of infestation, the types of growth, the natural 
conditions of the infested areas, and the amount of injury caused by defoliation. 
Areas were selected for which records of degree of defoliation in 1934 were 
available. One area was selected in Athol, 3 in Orange. 4 in Erving, and 8 in 
New Salem. Mass. This work has been under way for such a short time that 
it is hardly possible to draw very definite conclusions with respect to the 
effect of defoliation on all species of trees. It has been definitely established, 
however, that one complete defoliation is sufficient to kill hemlock, for in the 
Athol point 38 out of a total of 42 large trees of this species, ranging up to 
55 feet in height, were killed by being completely defoliated in the summer of 
1934. The other 4 trees in this group were not completely defoliated and 
still show signs of life. With respect to white pine, a section of the same 
point in Athol has quite a stand of small pines averaging about 5 or 6 feet 
in height. A count showed that one-sixteenth acre of this area contained 94 
small pines. All of these were heavily defoliated in 1934, and at present 
25 percent are dead and the remainder are in very poor condition. In all 
of the areas where white pines were selected within sections that were de- 
foliated, these trees suffered injury, depending on the degree to which they 
were eaten. If they were completely defoliated they were killed. At a hill- 
side location in Athol 42 pines ranging in height from 30 to 35 feet have died 
as the result of complete defoliation in 3934. Most of these pines attempted to 
refoliate after being stripped of their needles. Last winter they were more or 
less covered with the short, undeveloped new needles, but since then they have 
turned brown and are dead. For all of the 16 acres in which records are being 
taken the proportion of growth favored by the gypsy moth is rather high. In 
general, the growth most desirable for gypsy moth"' food consists in the main 
of white, red. black, and chestnut oaks, poplar, and gray birth. By actual 
and careful checks of the areas, which range in size from 2 or 3 up to 50 
acres, these favored food plants comprise from 30 to 95 percent of the entire 
growth, the general average being between 60 and 70 percent. White pine 
and hemlock, which have been eaten so heavily, comprise from 5 to 60 percent 
of the woodland growth, the average probably being about 20 percent. The 
remaining growth, which might be considered only partially or not at all 
favored, consists of paper birch and red maple, with a scattering of other 
species. It can be seen, therefore, that for most of the area where the 
records are being taken the ltowtIi is. in the main, extremely desirable to 
this insect, and this fact is attested by the cxinit of defoliation that has taken 
place in those areas. 
THE BROWN-TAIL MOTH 
In general, there was a light-to-medium infestation of this species through- 
out practically all of the infested territory, but no instances of appreciable 
defoliation were reported during the summer of 1934. During the winter of 
1934-35 numbers of winter webs wore cut by the Slates in Maine. New Hamp- 
shire, and Vermont. For Maine only partial records ;n v available, and this 
work was performed by men from three Civilian Conservation Corps camps, A 
total of 72,819 webs were cut and destroyed in 23 towns Located mostly in the 
southern part of the State. In New Hampshire webs were Cu1 in towns 
throughout the greater part of the infested area. A total of 1,548,287 webs 
