April, '13] • HODGKISS: PEAR PSYLLA 243 



and during each cleaning of the machine from one to two or three 

 gallons of insects would be removed. 



This sort of machine can be run at very slight expense and in those 

 blocks where it was run regularly during the summer it was impossible 

 to find any signs of curled leaves due to the injury of the pest. The 

 writer is of the opinion that if three or four applications of contact 

 washes of the oil type are made at intervals of three or four days in 

 the early spring when the first young nymphs appear and then follow 

 this up during the summer with a machine for catching the adults, 

 this pest can be controlled in any nursery at a very reasonable expense. 



FALL SPRAYING FOR THE PEAR PSYLLA 



By H. E. HoDGKiss, Geneva, N. Y. 



Life history studies on the pear psylla were continued by the station 

 during the past year for the purpose of determining more efficient 

 methods for the control of this pest, and special attention has been 

 given to the habits of the hibernating adults or "flies." Our investi- 

 gations have shown that these individuals remain on the fruit spurs 

 and young growth of the trees until the first severe cold weather 

 occurs in November, when they seek the protection of the loose bark 

 of the trunks and larger branches of the trees or hide under leaves 

 or other debris which may be in the orchard. The roughened bark 

 on adjacent trees of other kinds of fruits is often sought by them. 

 If there is a warm spell during the late autumn and winter the ''flies" 

 become restive and abandon their sheltered places to gather on the 

 lower branches of the trees, especially on the newer wood and fruit 

 spurs. Whenever the weather moderates to a marked extent few of 

 them remain in hiding, and where severe infestations exist myriads 

 of the tiny insects cluster in the center of the trees. At such times 

 the adults walk, but are sluggish in their movements and rarely at- 

 tempt to jump or fly. The short duration of sunshine and the daily 

 increasing cold cause a continual lessening of the activities of the 

 insects, which become numbed and cling to the wood for considerable 

 periods of time without exhibiting signs of movement. 



The behavior of the hibernating psyllas in the spring is quite dif- 

 ferent from the habits of the insects in the fall. With the conclusion 

 of winter the temperatures are constantly increasing and the daily 

 effectiveness of sunlight is correspondingly longer. Coincident with 

 moderation in the weather thousands of them leave their places of 

 concealment and often a few hours of time are sufficient to effect 

 great activity among the pests. It is not uncommon for them to 

 jump and fly directly after emergence from their winter retreats. 



