406 Report oF THE DEPARTMENT OF ENTOMOLOGY OF THE 
The failure to prevent losses to the fruit by the usual treat- 
ments for the codling moth and apple scab, and by special 
sprayings, has led some fruit growers to conclude that the 
tussock moth caterpillars cannot be killed by applications of 
arsenical poisons. The large numbers of damaged fruits in 
orchards that were sprayed one or more times would tend to 
support this belief. However, an examination of a number 
of orchards at the time of the appearance of injuries indicated 
that the principal reason why spraying was not generally suc- 
cessful was the lack of thoroughness in the first treatments. 
This was especially emphasized by the fact that, preceding the 
attack of the tussock moth, case-bearers had caused in many of 
these same orchards more than their usual amount of injury, 
which should have been prevented if the poisons had been well 
applied. The orchardist in his efforts to drive the poisonous 
spray into the leaf and blossom clusters is liable to neglect the 
undersides of the leaves, especially on the lower and inner 
portions of the trees where the tussock moth caterpillars, on 
hatching, are likely to feed. Thus, even in orchards where the 
spraying for the codling moth has been fairly well done, the 
young caterpillars may feed unharmed for a time on the under 
surfaces of leaves, and on the foliage of water sprouts on the 
larger limbs. 
HISTORY OF TUSSOCK MOTH AS A FRUIT PEST. 
The early records on the habits of the white-marked tussock 
moth indicate that it was a general feeder, and that it thrived 
on fruit trees, shade trees and shrubs. In 1828 Harris re- 
corded the caterpillars as very numerous on fruit trees 
throughout New England.t. Again in 1832 the eggs of this 
insect were observed on apple trees about Salem, Mass., by 
B. Hale Ives, who in the following year proved experimen- 
tally that collecting and destroying the egg masses is an effec- 
tive means for controlling this insect.2 Fitch® reported in 
‘Harris, “Insects Injurious to Vegetation,” p. 367. 
2 American Gardeners (Hovey’s) Magazine, 1:52. 
* Fitch. Rpts. 6-9, p. 199. 
