226 FRUIT INSECTS 



larvae bore their way out through decayed spots. They 

 burrow into the soil an inch or two, and after a variable time 

 spin delicate cocoons within which the insect hibernates. 

 Most of the larvse spin cocoons within a month after entering 

 the ground, but some are found naked as late as October. As a 

 general thing the winter is passed in the pupal stage, but some- 

 times a large percentage of the larvse may not pupate until 

 spring, about two weeks before the flies emerge. When about 



to transform the pupa 



ft«% 



leaves the cocoon and 

 works itself to the sur- 

 face of the ground, 

 where the fly is set 

 free . There is only one 

 generation a year, al- 

 though it has been ob- 



Fig. 205. — Young pears infested by the pear served in France that 

 nudge, cracked open to permit the escape of the 



larvse. some oi the nrst larvae 



to pupate transform to 

 flies during July of the same year. As there are no pear 

 blossoms available at that time and as they have no other 

 food-plant, these precocious individuals necessarily perish. 



Remedial measures. 



So far no method of sprajdng has been devised to prevent 

 the laying of the eggs or the development of the larvae in the 

 fruit. The infested fruits are easily distinguished by their 

 size and shape, and where only a few trees are affected it would 

 pay to collect and burn them before the larvae have emerged, 

 that is before May 15. In larger orchards this would be too 

 expensive to be practicable. Experiments in New Jersey have 

 shown the great value of kainit in destroying the larvae in the 

 ground. It should be applied during the latter half of June, 

 at the rate of 1000 to 2000 pounds to the acre. While it has 

 been successfully used on the sandy soils of New Jersey, the 



