204 THE APPLE 



The pupa. On the emergence of the larva, it digs its way into 

 the earth, where it is transformed after a few days into the pupa. 

 The depth to which it tunnels the soil varies, but rarely exceeds 

 three inches. A pupating cell is prepared by the twisting and turning 

 of the worm. In this the pupa remains dormant and inactive until 

 it has reached the final (or beetle) stage, when, conditions being 

 favorable, it at once forces its way to the surface. The subter- 

 ranean life of the curculio is extremely variable and is largely 

 governed by the condition of the soil. A moist soil hastens the 

 emergence of the beetle, while a hard, baked condition greatly 

 retards it. The average subterranean life of the beetle in loose, 

 moist earth is about three weeks. 



Soon after emergence the beetle renews its feeding upon fruit, 

 this time by gouging out holes with its long snout, thereby making 

 the circular punctures so commonly found in fruit in the fall. It 

 sustains life by these depredations until the approach of winter, 

 when it goes into hibernation in such protected places as are most 

 readily found. In the early days of the following spring the beetles 

 reappear, mate, and soon begin egg-laying in the fruit left exposed 

 by the falling of the blossoms. 



Treatment. By means of thorough spraying with arsenate of lead 

 just after the blooms are off, the apples may be rendered relatively 

 immune from the curculio egg-laying and feeding. The first appli- 

 cation of arsenate of lead for the codling moth is rightly timed to 

 give a protective coating of poison against the earlier activities of 

 the curculio. Apples at that time have a pubescent growth which 

 is retentive of liquid spray. A second spraying a week or ten days 

 later (as recommended for the codling moth) is of more value 

 against curculio than if applied several weeks later. The spray 

 material adheres much better to the surfaces of apples and foliage 

 after one or two applications. The solids deposited hold subse- 

 quent sprayings, and aid in securing a thicker and more uniformly 

 distributed investment of poison. For this reason two sprayings 

 should be administered in quick succession. 



The habit of the plum curculio in pupating at a shallow depth 

 in the soil renders it peculiarly liable to destruction by the clean 

 cultivation of the orchard. Light surface harrowing either destroys 

 the beetles or so exposes them that they ultimately perish. 



