78 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. & 



of maple and ash were allowed to remain. On one side of the area 

 large pines predominated which were mixed with gray birch and an 

 occasional oak. The last two species were removed leaving a pine 

 stand with an occasional maple, chestnut, or ash tree. The brush was 

 cut over the entire area except the seedlings and sprouts of the same 

 species as the trees left standing. No gipsy moth injury has been 

 observed during the summer of 1912, frequent observations having 

 been made by Mr. H. R. Gooch, who had charge of the thinning opera- 

 tions in this and several other selected areas. The infestation appears 

 to be about the same as it was last year. Other areas have been thinned 

 leaving solid pine and hemlock stands and no injury has resulted to 

 the trees during the past summer. In one case a remarkable decrease 

 in the number of egg clusters has been noted, while in the adjoining 

 unthinned block a slight increase has been observed. 



It is apparent that it will be necessary for a number of years to pass 

 before the final results of this work can be given, but the information 

 at hand is of such practical importance to owners of woodland that it 

 seems well to make pubhc the results that have been secured. In 

 this connection it should be said that very thorough and detailed 

 observations are being made, both in the field and by means of labora- 

 tory tests, to secure exact information on the feeding habits of gipsy 

 moth caterpillars in each stage and on all the food plants which are 

 common to New England. The data secured during the past summer 

 are not yet ready for publication, but the results indicate that the oaks 

 should be eliminated as rapidly as possible from our woodlands. 



While they are the chief offenders they are not the only species that 

 should be eliminated. Gray birch is a common species and is of low 

 value as far as the wood is concerned. In some cases it is useful as a 

 nurse crop for pine but its susceptibility to gipsy moth attack renders 

 it a dangerous companion for the latter. Neglected or wild apple 

 and willow trees should be destroyed as they furnish attractive food 

 for the caterpillars. First stage gipsy moth caterpillars do not feed 

 freely on pine or hemlock and the same is true in regard to some of 

 our hardwood trees. In fact, it is exceptional for first stage cater- 

 pillars to grow and develop w^hen their diet is confined to certain species. 

 If half-grown or larger caterpillars feed on the same plants a large 

 percentage of them will develop and if the same thing happens in the 

 field where the infestation is at all severe, defoliation by the larger 

 caterpillars often results to species which are not jjarticularly favored 

 as food by the younger larvae. 



From the present data it appears that oaks of all species are the 

 greatest menace to improvement and development of New England 

 forests as far as the gipsy moth is concerned. If these were cut the 



