358 CONTROLLING INSECTS AND DISEASES 



It is not possible to include here a complete treatment of the various 

 insects and diseases that affect fruit trees. Some are serious in one sec- 

 tion and less so, or not at all, in another. Some are seasonal in their 

 inroads, being destructive one year and unimportant another. New 

 and more complete knowledge concerning them and the methods for 

 their control is constantly being acquired and is available from authori- 

 tative sources. The enterprising grower will keep in touch with the 

 experiment stations and government agencies and will study their find- 

 ings. He will develop a library of good books and publications on the 

 control of insects and diseases of the orchard and will revise it con- 

 stantly to keep it up to date. 



GENERAL INFORMATION 



Controlling Peach Tree Borer 



The peach tree borer (Sanninodea exitiosa) kills many peach trees 

 and destroys the vigor of others. It passes the winter in the larval form : 

 if anall, usually on the bark in silken protective coverings; if larger, in 

 burrows under the bark. In the far South the larvae feed all winter 

 instead of hibernating. 



In the spring the boring is continued and a cavity is formed several 

 inches long in the sapwood, just beneath the bark. Gum and sawdust 

 collect at the openings of the burrows and about the base of the tree. 

 As many as 50 or more borers may work in a single tree. Most of the 

 work is done about the trunk just at or below ground level, though 

 sometimes at a greater depth. 



. When full grown, the larva leaves the burrow and pupates in a dark 

 round cocoon, usually attached to the bark near the ground. The adult 

 fly emerges in about a month, and eggs are soon laid by the female, 

 singly ar in small clusters on the lower trunk. The eggs hatch in about 

 ten days, and the larvae start their burrows at once. 



Control. Larvae may be dug out with a knife and wire. This 

 method is not so satisfactory as the use of ethylene dichloride. 



Slowly stir 9 parts by volume of ethylene dichloride into 1 part 

 by volume of potash fish-oil soap. Add 9 parts of water to make a 50 

 percent stock emulsion. Dilute, and apply as recommended in Table 44. 

 This material may be sprayed or poured on in the fall, winter, or early 

 ^rmg as long as the weather is warm. Apply the emulsion about the 

 base of the tree and on the lower trunk. A knapsack sprayer or a 

 sprinkling can with a small spout may be used to advantage. Place a 



