76 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. & 



area. No other treatment was applied and no injury resulted to the 

 trees. 



During the following two years observations were made on the 

 feeding habits of the gipsy moth caterpillars by various observers, 

 and in 1910, when bulletin No. 87 of the Bureau of Entomology was 

 published, covering a report of the field work against the gipsy and 

 brown-tail moths, enough information had been secured so that the 

 authors felt warranted in making the following statements. 



On page 14 it is stated that the gipsy moth has a varied list of food 

 plants, "in fact, it will eat almost any kind of vegetation, although 

 it seems to prefer the fohage of oaks, willows, and apple trees. Re- 

 peated observations have shown that the ash, juniper, and red cedar 

 are practically immune from attack, while the maple is not injured 

 to any great extent if more desirable food is within easy reach." As 

 a result of these observations it was recommended, pages 73 and 74, 

 that "owners of woodland on which the trees are of marketable size 

 should cut the timber if the gipsy moth is prevalent in the region. 

 Care should be taken in doing this work to cut out all poor and worth- 

 less trees, and if possible to leave for reforesting purposes, vigorous 

 specimens of ash, maple, pine, or coniferous trees of which the insect 

 is not especially fond and which can be protected with the least pos- 

 sible expense. The planting or preservation of ash and hickory 

 is recommended as the wood is of high value and these trees are not 

 subject to attack by the brown-tail moth. Planting pine or other 

 coniferous trees for reforesting purposes is also advisable, as the 

 region is suited to their growth and these can be protected from moth 

 injury at slight expense. It is probable that many of the forests 

 containing oak or other trees which are preferred by these insects 

 must in time give way to species less subject to attack. In the mean- 

 time the owner should take advantage of the opportunity to harvest 

 his merchantable trees that are susceptible to attack and foster the 

 growth of other species that will not be destroyed." 



After the publication of this bulletin more observations were made 

 on the food plants of the gipsy moth and Mr. Rogers became so 

 thoroughly convinced of the practical utility of eliminating the trees, 

 which were most favored by this insect, that in the winter of 1910-11 

 much consideration was given to the subject by him and several 

 experiments were carried on, on a large scale to determine what would 

 happen if forest areas were thinned to solid blocks of species which 

 had frequently been observed to withstand defoliation. 



An area was selected near Chelmsford Center, Mass., where the 

 tree growth was chiefly chestnut, with some gray birch and oak, and 

 where the infestation was heavy. Seven acres were used for the. 



