132 Bulletin 76 



no doubt that the plan could be very advantageously carried out when the 

 eggs to be collected were those of the forest caterpillar. As to this Slinger- 

 land' writes : "Just such a crusade has been successfully carried out even 

 in so large a city as Rochester, N. Y. We believe that there is no cheaper 

 method of controlling these forest tent caterpillars in village shade trees." 

 It is scarcely necessary to add that the time to seek and destroy the eggs is 

 after the leaves have fallen in the autumn and from this time on until they 

 appear in the spring. I do not suppose that it is practicable to do very 

 much in this way in the large sugar groves, but in those that are not too 

 large I am sure that it would pay to try it, especially if there are no other 

 groves near by that have been infested. It seems at first thought a hope- 

 less task to go over a large tree and utterly useless to attempt to go over a 

 grove ; but actual experience has shown that it can be done, at least to an 

 extent that is of great value, and with less labor than was expected at the 

 outset. 



SPKAYING TO DESTROY THE YOUNG CATERPILLARS 



Nothing can be done in the spring, after the eggs have hatched until 

 the leaves have opened sufficiently to allow spraying. This would not be 

 until after. the first of May. By this time the caterpillars will have ordinarily 

 been able to do some damage, but if now the leaves on which they are feed- 

 ing can be well poisoned the career of the enemy will come to a sudden end. 

 Any tree or trees of moderate size can be effectually protected by thorough 

 spraying. The sooner this is done after the leaves are expanded the more 

 likely it is to be effectual, as less damage is done of course early in the sea. 

 son than later, and, too, the caterpillars are more easily killed when small- 

 Indeed, some authorities assert that spraying is of little use unless done 

 before^he caterpillars are half grown. Spraying to be most effectual should 

 be done in this state about the first of May and certainly before the end of 

 the second week in May. 



Probably the best poison to use on maple and apple trees is paris green 

 five ounces in a forty gallon cask of water, to which is added a pint of fresh 

 lime water. Arsenite of lead, which has been very extensively and success- 

 fully used by the Massachusetts gypsy moth commission, is excellent for 

 all sorts of trees and is less likely to injure the foliage than paris green. 

 This can now be bought from almost any large dealer in insecticides. 

 Spraying will also be found useful against any leaf eating -larvaj, such as 

 the fall canker worm, so abundant last fall in many parts of the state, 

 that may be infesting the trees in company with the forest caterpillar. 



DESTROYING THE CATERPILLARS WHEN CLUSTERED 



If no remedial measures have been taken until the caterpillars are 

 well gr own, it is then better to attack them with kerosene or-its emulsion. 



I N. Y. (Cornell) Sta. Bui, 170, p. 56s (1899), 



