Apr. 1. 1918 Laspeyresia Molesta 63 



however, a small amount of frass is left at the point of entrance. ThQ 

 small larvae may tiot be discovered even after opening the fruit, for at 

 first they work along the grooves in the seeds. Another favorite point of 

 entrance is between two peaches which hang against each other or on 

 the surface of a peach on which d leaf is resting (PI. 6, A). This seems 

 to give the larvae a better foothold than they can find on the open surface 

 of the fruit. 



The fourth-brood larvae begin to hatch in time to attack late-ripening 

 Elberta and varieties that ripen still later, Smock being badly damaged. 

 The attack continues until late in the fall after all peaches have been 

 picked. 



Larvae of the fifth generation that hatch early may appear in time to 

 attack the latest-ripening varieties of peaches, but their work is confined 

 mostly to the peach twigs, where they cause little injury, and to the 

 pome fruits, such as quince and apple. 



Injury was not noticed on the pome fruits until late in August, and 

 it is thought that before this time they are not heavily attacked. Later, 

 however, the infestation appeared to b,e serious. From 1% bushels of 

 medium-sized Ben Davis apples showing signs of injury (PI. 7, A, B) 

 354 larvae of Laspeyresia molesta were reared. Fifty per cent or more 

 of the fruit in the orchard from which these apples were taken were 

 injured. In another apple orchard about a half mile distant from the 

 infested peach orchard very little injury was found. Quince was more 

 severely injured than apple (PL 6, B). In a row of several trees not a 

 sound fruit could be found, and, as mentioned before, the average 

 number of insects reared from each of 10 quinces, picked at random, was 

 more than 9 per fruit. Even though commercially the injury to pome 

 fruits might not be severe, such food plants are of great importance in 

 that they affect materially the problem of control by furnishing food 

 for the insect in the fall after other fruits have disappeared. The mor- 

 tality among newly hatched larvae is probably very great in peach orchards 

 after the twigs have hardened and the fruit is gone, but quinces, 

 apples, or pears furnish an ideal place for the development of the late 

 broods. Such fruits in the vicinity of a peach orchard doubtless form 

 a reservoir from which the infestation spreads the following spring. 

 Cherry and plum ripen too early in the season to be severely injured by 

 this insect. On several cherry and plum trees growing beside an infested 

 peach orchard not one injured fruit was found. 



As previously stated, the periods of attack by the first, second, and 

 third generations do not overlap, and there is a period between each 

 generation when no insects can be found working in the twigs or fruit. 

 The larvae of the third and of the following generations appear over a 

 much longer period of time and before the latest individuals of one 

 generation have developed the larvae of the following generation are at 

 work. Because of this overlapping of the later broods it was not pos- 

 41811°— 18 5 



