other words, we can not rely for assistance upon any of the natural ene- 

 mies except birds. These should be encouraged in every possible way, 

 and warfare should be waged against the English sparrow, which does 

 not feed on this caterpillar, save perhaps occasionally in nesting time, 

 and is a great pest in itself, especially as it drives other and useful 

 birds from cities and towns, 



REMEDIES. 



Arsenica^.— Spraying with an arsenical mixture, if accomplished 

 when the caterpillars are young, is the most effective means of con- 

 trolling this insect, but a spraying is not easily applied when a large 

 grove of maples is infested. Either Paris green or arsenate of lead 

 may be used and applied in accordance with the directions furnished 

 for other shade-tree defoliators, as described in detail in Farmers' 

 Bulletin No. 99. This publication should be in the hands of all per- 

 sons suffering from the ravages of shade-tree insects, and that portion 

 relating to general instructions in the last chapter should be read." 

 Paris green may be applied on maple trees as strong as 1 pound to 50 

 gallons of water, but half that strength, or one-half pound to 50 gallons 

 of w^ater, will probably suffice in most cases. Arsenate of lead ma}^ 

 be safely used at as high a rate as from 2 to 4 pounds of the poison to 

 50 gallons of water. 



Trenching. — If an arsenical spray has not been used while the larvae 

 are young, large numbers of the pests may be trapped and easily 

 destroyed by digging a trench either around individual trees or around 

 groves or belts of trees. The trench should be at least a foot deep, 

 with the outer walls sloping under. The larv;© usuall}" wander away 

 from the trees before entering the earth, and will ])e caught in the 

 trench in great numbers or will bur}^ themselves in the ground in the 

 bottom of the trench, where they can be killed. This remedy was 

 given a practical and thoroughly satisfactory test many years ago 

 by Doctor Riley, and has been recommended to our correspondents 

 generally. 



Hand picking. — When the public once becomes well acquainted 

 with this insect in all of its stages, from the ^gg to the moth, large 

 numbers of the eggs and the moths can be killed by hand on their 

 appearance in May or June, and individual choice trees may in a 

 measure be protected in this manner. 



Approved : 



James \^^ilson, 



Searetai'y of Agriculture., 



Washington, D. C, May 26, 1900. 



a Farmers' Bulletin No. 99 is furnished gratis on application to the Department of 



Agriculture. 



[Cir. 110 



o 



