18 FARMERS’ 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 isolatea 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 larve 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 plant of this 
insect, and unfortunately the infested region abounds in large 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 
ereatly 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 
