1909.] PUBLIC DOCUMENT --No. 73. 49 



THE GYPSY MOTH v. WHITE PINE. 



In the last report of this department (page 163) this subject 

 was discussed in a conservative manner, and details were given 

 of a certain number of experiments with young gypsy moth 

 caterpillars on white pine foliage, tending to show that in 

 the early stages of their existence these insects could not live 

 on white pine alone. Because of the importance of this dis- 

 covery, if true, Mr. Kirkland preferred to take conservative 

 ground, and await the results of the larger series of experi- 

 ments in 1908. Fortunately for the thorough testing of the 

 matter, there was found in the fall of 1907, at Arlington, 

 Mass., on the property of Mr. F. A. Pierce, an area of 10 acres 

 of white pine free from deciduous growth which was generally 

 infested by the gypsy moth, some of the trees bearing hundreds 

 of egg clusters. In co-operation with Mr. D. M. Rogers, Field 

 Agent of the United States Department of Agriculture, these 

 trees were banded early in the spring with the sticky preparation 

 known as tanglefoot. Upon the hatching of the eggs the young 

 caterpillars spun downward in large numbers to the ground, or 

 died in the foliage of the trees. The bands, which were kept 

 fresh for a period of about ten days, prevented their ascent, 

 and, although the tree tops were literally full of the young 

 insects, not a single pine was defoliated, and at the time of the 

 fall inspection only 14 new egg clusters could be found in the 

 entire area. The accompanying photographs, taken at the height 

 of the caterpillar season, show the effectiveness of this method of 

 treatment. This experiment on a large scale seems to give final 

 and conclusive proof that where the hardwood growth is thor- 

 oughly destroyed in a pine forest, there need be no fear from 

 damage by the gypsy moth caterpillars, provided the trees are 

 properly protected from invasion from without by the use of 

 sticky bands. 



At Beverly, Mass., in the center of a large wooded area, 

 about 3 acres of large white pines were found badly infested 

 by the gypsy moth during the winter of 1907-08. Here all 

 hardwood growth and brush were removed, and a limited pro- 

 tective belt cut around the pines. ]STo further care was given 

 to this colony. N"o egg clusters were treated or spraying done, 



