382 REPORT OF STATE BOARD OF HORTICULTURE. 



ting their full growth in June. (See Fig. 46). They then leave their burrows 

 and spin about themselves a brown cocoon (Fig. 48) at the base of the tree, 

 usually at the surface of the soil. A few days after its cocoon is made, the 

 borer changes to a pupa (Fig. 49) in which stage it remains for about three 

 weeks, usually in June in New York. From the pupa the moth emerges, 

 thus completing its life-cycle in a year, fully ten months of which are usually 

 spent as a borer in the tree, the remainder or a little more than a month 

 being spent in the egg, pupa and adult stages. About the middle of July all 

 stages of the insect may be found in some orchards. The above brief sketch 

 of the life of the peach-tree borer will apply in general to most localities in 

 the United States north of Washington, D. C. In Canada the moths do not 

 begin to fly until about a month later, while in the South they appear a 

 month or more earlier, so that the dates in the above sketch will not apply 

 to these regions. 



ITS NATURAL ENEMIES. 



As the peach-tree borer spends most of its life under the bark beneath 

 the surface of the soil, it is not readily accessible to enemies. But it does 

 not entirely escape, for several insects have discovered a way to include 

 this serious peach pest in every course served to their growing progeny. 

 At least eight different enemies of the peach-tree borer have been found, 

 and all of them are parasitic Hymenoptera. 



There are indications that in some localities the enemies of the peach- 

 tree borer may play quite an important part in checking the normal in- 

 crease of the pest. 



SOME GENERAL CONCLUSIONS REGARDING METHODS OF 

 EIGHTING THE PEACH-TREE BORER. 



Although American peach growers have been fighting the peach-tree 

 borer for a hundred and fifty years, the results from to-day's methods of 

 warfare are not strikingly different from those recorded by Peters in 1806. 

 Most of the applications now recommended were devised nearly a century 

 ago. 



Cultural methods — Different cultural methods such as budding on various 

 stocks, irrigation, and cultivation seem to have little or no effect upon the 

 number of the borers. But to make a success of peachgrowing it is usually 

 necessary to thoroughly cultivate and feed the trees, and we believe the 

 borers can be • controlled more successfully and much easier in such an 

 orchard. 



Our experimenix — During the past five years we have conducted the most 

 extensive and scientific series of experiments ever attempted. An experi- 

 mental orchard of four hundred peach trees was set for the sole purpose of 

 testing the so-called "remedies." Portions of this orchard are shown in 

 Fig. 52 and 53. The details of the plan and extent of these experiments ai'e 

 discussed in the unabridged edition of this bulletin. We thoi-oughly tested 

 about twenty-five representative methods for combating the peach-tree borer. 

 Vulnerable stage of the insect — The insect is open to successful attack only 

 in its larva or borer stage and in its pupa stage ; the pupae are reached only 

 by searching for the cocoons and destroying them. 



