The Plum and Apple Curculio. 257 



period spent by each individual in its subterranean burrow is about 

 four weeks, although some complete their transformations in three 

 weeks and others require as much as five weeks. But since at no one 

 time are all the curculios in the ground, some of them being in the 

 egg or larval state while earlier ones have long since emerged as 

 adult beetles, it follows that the entire period in which curculios 

 are to be found underground is of no considerable length. Approxi- 

 mately it extends from the middle of June to November, but there 

 is a period during July and August when the great bulk are in the 

 ground together, either as newly arrived larvae, pupae or adults ready 

 to emerge. As we have seen, these pupae are only a short distance 

 below the surface, over one-half of them buried less than one inch 

 and practically all of them under two inches, so it follows that light 

 cultivation of the surface soil with a disk or harrow would disarrange 

 the burrows and bring the delicate pupae to the surface where they 

 would be exposed to the elements and perisli in a short time. It 

 has been shown that direct sunlight will kill them very quickly, while 

 on a warm day tliey cannot survive long even in the shade. The exact 

 time wlien the greatest number of pupae could be thus exposed varies 

 greatly with the season; three applications of the disk at least, and 

 more if possible should be made, one probably a little before the middle 

 •of July, another during the latter part of that month or early in 

 August, and a third in middle August. These diskings would disturb 

 nine-tenths of the pupae and result in the death of a very large pro- 

 portion of them. The remedy next in importance is the 



2. Destruction of Fallen Fruit. The object in destroying this 

 fruit is to kill the larvae developing therein. We have seen that the 

 ■curculio attacks the fruit quite extensively even when it is very young, 

 so the earlier fallen, very small fruit should be destroyed even more 

 ■carefully than that which falls later. It is often a matter of difficulty 

 dn orchards of considerable extent to devise a practicable means of 

 gathering up this fallen fruit, a process which should be repeated 

 ■every few days. In open cultivated orchards much of it will be exposed 

 to direct sunlight which in itself is quite sufficient to kill the larvae; 

 in other cases the fruit might be raked together in a spot whe^e 

 the sun could reach it. Much good will be accomplished during 

 •cultivation, for many of the larvae will be crushed when the fruit is 

 ■cut up by the disk. This remedy also applies primarily to the plum 

 curculio, since we have seen that apples attacked by the apple curculio 

 do not usually fall, but it is also of considerable avail against the 

 ■codling moth. An old remedy for the plum curculio which is very 

 lielpful in small orchards is the 



