INSECTS 203 



This treatment by jarring has been found to be impracticable, 

 however, and inordinately expensive. 



The egg. A large number of the eggs never hatch. One reason 

 is improper fertilization ; another is the condition produced in the 

 egg cavity by the drying out of the tissues immediately surround- 

 ing the egg, and the heat to which it is subjected when exposed 

 to sunlight in this relatively moistureless environment. Under 

 such unfavorable conditions the egg collapses and the contents 

 become thin and watery. 



The greater part of curculio injury is found not in the actual 

 destruction of the apple, but in the misshapen and blemished fruit 

 caused by early-season egg punctures. Most of the eggs are de- 

 posited within the first six or eight weeks of the apple's life. These 

 eggs are usually accompanied by the characteristic crescent mark 

 of the female curculio's puncture, and with the growth of the apple 

 the crescent cuts produce an atrophied growth at the point of inci- 

 sion, resulting in a malformation of the apple at that point. Later 

 the wound heals over, but the skin forming the cicatrix is thick- 

 ened and russeted. By the time the fruit is ripe for picking, this 

 russeted skin has enlarged until it is the size of a dime, with an 

 irregular outline. Very often there are several of these scars on 

 a single apple. 



The larva. Four or five days after it is laid, the egg is hatched 

 into a minute, footless grub nearly white in color and with a dis- 

 tinct, brown head. At first very small, it grows rapidly with feed- 

 ing until ready to emerge, attaining a length of about a third of 

 an inch. The larva rarely goes to the core, as does the codling- 

 moth larva, but eats its way into the flesh of the apple, leaving 

 a brown, grainy ordure in its wake. Small apples often are com- 

 pletely emptied of their contents, save for the castings of the 

 departed worm. In about three weeks from hatching, the larva 

 emerges and goes into pupation in the earth. 



Larval mortality. Very few larvae ever succeed in attaining 

 full growth in the apple. They perish before half grown, leaving 

 as the only evidence of their occupancy a hairlike line, dark green 

 against the white flesh of the fruit. The tissues along this line 

 harden, becoming bitter to the taste and impairing the flavor of 

 the apple to that extent. 



