Apr.i. i9i8 Laspeyresia molesia 71 



Of the two secondary parasites, Dihrachys houcheanus (Ratzeburg) 

 pupated within and was reared from cocoons of Macrocentrus sp., already 

 mentioned as a parasite of L. molesia. Of three specimens of Ceramby- 

 cobius sp. (Q. 5195), two were found in cocoons of Macrocentrus sp. 



OTHER NATURAL ENEMIES 



A small spider was observed to kill a partly grown larva of L. molesia. 

 The larva was evidently migrating from one feeding place to another when 

 captured. On two occasions larvae of lacewing flies were seen with the 

 larvae of L. molesia in their mandibles. In a few instances cocoons were 

 found torn open and contents removed, evidently by woodpeckers. 



CONTROL MEASURES 



Because of its habit of feeding inside of the twigs and fruit, no success 

 was obtained in controlling the insect on peaches by the use of poisoned 

 sprays. Arsenate of lead, though applied to the fruit, foliage, and twigs 

 just before the eggs were due to hatch, did not prevent the larvae from 

 entering the twigs and fruit and gave no degree of control. Other appli- 

 cations in addition to this one, made at such times as it was thought the 

 insect would be most vulnerable to attack, gave no better results in 

 control. A 40 per cent nicotine sulphate solution, diluted to i part in 

 400 parts of water and applied in the same way and at the same time as the 

 treatments with arsenate of lead, did not control the insect; although 

 counts made early in the season of the number of infested twigs on the 

 sprayed and unsprayed plats seemed to indicate slight benefit from the 

 treatment. A combination spray of lead arsenate and nicotine sulphate 

 likewise gave negative results. 



Banding the trees with burlap resulted in the capture of a few larvae, 

 but most of the insects, after leaving the twigs and fruit, spin their 

 cocoons around the fruit spurs, on the peaches, and in the axils of the 

 twigs, thus making this operation a failure. 



Clipping the infested twigs from the trees and destroying them, and 

 destroying infested fruit, gave partial control, but was too laborious to 

 be practical. 



Tests were made of the killing power of miscible oils and nicotine 

 sulphate when applied to the cocoons containing overwintering larvae, 

 and when applied directly to the insects by immersing them in the 

 liquid. A number of larvae in cocoons were immersed for 17 hours in 

 a miscible oil diluted in water at the rate of i part in 10. Several hours 

 after removal from the solution one-third of the larvae appeared to be 

 uninjured and were spinning new cocoons. The balance were almost 

 inactive but none was dead and none died within a week. A similar 

 test was made using 40 per cent nicotine sulphate at a dilution of i to 

 233 combined with the oil solution used above. The larvae after removal 



