86 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



51: 49 per cent, respectively, and averaged 36 per cent transforming 

 larvae and 64 per cent wintering larvae. 



The larvae of either brood shed the skin (molted) five times, and 

 had thus six "instars." A limited number of larvae molted only 

 four times. 



A hymenopterous fly, Ascogaster carpocapsse Vier., was found to 

 parasitize from 6 to 7 per cent of the larvae of the codling moth. 



Hibernating codling-moth larvae succumb extensively to the cold 

 during the winter. From 25 to 35 per cent were found to be killed. 



From the foregoing records of the life history of the codling moth 

 and from the variability of results obtained, it is evident that reliable 

 data can only be obtained from a large number of observations. 



From the point of view of mechanical control of the codling moth 

 the most important observations of the habits of the insect relate to 

 the time of emergence of the moths in the separate broods. Such 

 observations should preferably be made from carefully conducted 

 band records. It is essential that the collecting of larvae from the 

 banded trees should commence sufficiently early in the season so 

 that the first-appearing larva may be secured. It is also of importance 

 to make the collections at regular and frequent intervals (three days) 

 and for the entire season. Apple trees of late varieties should be 

 selected whenever available. 



On applying the results of this investigation to the present methods 

 of controlling the codling moth in Michigan it will be found that the 

 poison-spray applications should be most effective when applied at 

 the following periods : 



First. — Shortly after the petals drop, to fill the open calyx cup and 

 thus destroy the larvae which hatch later. It is the habit of most of 

 the first-brood larvae to penetrate the apple through the calyx end. 



Second. — From three to four weeks after the petals have dropped, 

 when the first-brood larvae commence to hatch. 



Third. — Ten weeks after the petals have dropped, when under 

 normal seasons the first larvae of the second brood commence to 

 appear. During advanced seasons the above period may be short- 

 ened to nine weeks and only very exceptionally to eight weeks, as 

 noted in 1911. 



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