18 FABMEBS' BULLETIN 564. 



more valuable when the land is subdivided. Limited areas of wood- 

 land on private estates may be of sufficient value to the owners to 

 justify a considerable expenditure for moth destruction. In all cases, 

 however, the species of trees involved should be carefully studied be- 

 fore a plan of work is adopted in order that the expense may be re- 

 duced as much as possible. Unfortunately the difficulty of treating 

 the woodlands in the infested area of New England is considerably 

 increased by the fact that they are for the most part composed of a 

 variety of species in mixture. 



Experiments have shown that coniferous trees are not injured by 

 the gipsy moth if grown in isolated pure stands, and if the growth 

 is such that the trees can be thinned to a stand of conifers no hand 

 suppressive measures are necessary in order to prevent injury by this 

 insect. (See fig. 10.) Such lots will also be immune from attack by 

 the brown-tail moth, as the larvae of this insect do not feed on conifers. 



If mixtures containing a large percentage of deciduous trees are to 

 be protected from moth injury it is very necessary that the species 

 involved should be carefully considered before a decision is reached as 

 to the best methods of treatment. Sometimes practical methods of 

 thinning can be adopted so that species will be left that are only 

 slightly subject to injury by these insects. A limited number of ex- 

 periments have shown that mixtures of chestnut, pine, red maple, ash, 

 and hickory, regardless of the proportion of each species, are seldom 

 injured by the gipsy moth. 



In woodlands the oaks are the most favored food plaat-of this 

 insect, and unfortunately the infested region abounds in fl^e areas 

 where these species predominate. At present there seems to be no 

 means aside from hand treatment which will prevent serious injury 

 to oak woodland, but as a large part of such land consists of poor 

 sprout growth the amount of damage sustained is not always so 

 great as it might at first appear. The greatest injury likely to be 

 caused in such areas where oaks and gray birch abound is the dying 

 of small seedlings of pine or other valuable species which have been 

 denuded by the caterpillars after the oaks and birches have been 

 defoliated. This leaves the prospective woodland in a much worse 

 condition than it was before the defoliation took place and reduces 

 greatly the chance that the sprout growth will be replaced by any 

 .species of value that can withstand gipsy-moth attack. This problem 

 is being given special study and consideration in the hope that some 

 economical method may be -devised for protecting and improving 

 wood lots of this character at moderate expense. It is true that 

 there are considerable areas of oak woodland where the trees, al- 

 though not mature, could be utilized for small timber, railroad ties, 

 or cordwood, and in cases of bad infestation such woodland should 

 be promptly cut if the wood can be sold to advantage. On cheap 



