208 Bulletin 176. 



soiiri (Bull 35 of the Mo. Exp. Station), and in some Oliio experi- 

 ments (Bnll. 106 of tlie O. Exp. Station) peacli trees were killed by 

 injecting it around them. 



Carbon bisnl})liide is too expensive and too dangerous to use 

 against the peach-tree borer, and we have no evidence that it is an 

 effective way of fighting the insect. 



The " digging-out " method. — This method was one of the first 

 to be used by peach-growers, and it is to-day more universally prac- 

 ticed than any other method. Its name well describes the n\ethod. 

 After removing a little of the soil from around the base of the tree, 

 the presence and usually the location of a borer is readily deter- 

 mined in a peach tree by the gunmiy mass exuded from the wound 

 made by the borer . Sometimes it is a little difficult to locate and 

 reach a borer which is working far down on a root. When once 

 their burrow is located it is usually an easy matter to kill them with 

 the knife or a wire. With a little experience one can often locate 

 and kill the borers with but little injury to the tree from the " dig- 

 ging-out" process. The peach tree so quickly repairs such wounds 

 that one should not hesitate to use this method for fear of doing 

 more injury with the knife than the borers would do. 



Some of the most extensive peach-growlers first have a man hoe 

 the soil and gum away from around the base of the trees and leave 

 it thus exposed for a few days. In the meantime, the fresh excre- 

 ment and gum resulting from the borers' work renders it easier for 

 one to locate them then, than to do so when the soil is first removed. 



When is the best time to dig them out f In the peach-growing 

 districts north of Washington, D. C, the ideal time would be in the 

 fall in September or later, or in April the next spring. By Septem- 

 ber most of the borers have hatched from the eggs but have not 

 done much damage. And usually most of them do not get half 

 their growth before it is time for them to stop eating and go into 

 liibernation ; and they usually do not begin feeding in the spring 

 before the latter part of April ; thus they get most of their growth 

 and do much more damage in May and June. Therefore, by dig- 

 ging them out in September or April one can catch the rascals 

 before they have done much damage in northern localities. But 

 the borers are then so small that many will be missed, enough to 



