August, '12] 



BACK AND PRICE: STOP-BACK OF PEACH 



331 



that they were causing the Stop-back. They were found sucking the 

 sap from the terminal buds. There were noted perfectly healthy termi- 

 nals from which bugs were sucking the sajj, slightly'- and badly wilted 

 terminals, as well as dried and blackened terminals. Close observation 

 over a large area clearlj^ indicated that Lygus pratensis was causing 

 the damage. The injury was, generally speaking, in proportion to the 

 abundance of bugs as previously noted by Webster and Mally in Ohio. 

 In some instances, leaves close to the terminal bud were blackened 

 as a result of the feeding of the bug while the bud itself was unaffected. 

 Several hundred affected buds showing all stages of Stop-back were 

 collected and of these, one hundred were examined by the senior writer 

 in the laboratory and but one mite and three thrips were found. 

 The bugs were noted to thrust their beaks into the tip of the tender 

 shoots to their full length. Examination of shoots dying but not yet 

 blackened, showed discolored streaks in the plant tissues corresponding 

 in length with the beaks of the bugs. 



An examination of the trees at 2 p.m., sun bright and hot, gave the 

 results in Table I. - 



Table No. 1. Relation Between Number of Trees Affected and Abundance of the 

 Tarnished Plant-Bug 



In some instances, as many as seven bugs were found on one plant. 

 As the insects flew from the plants on the slightest provocation, it is 

 thought that the number counted was smaller than was actually pres- 

 ent. On June 1st, the trees were again examined and over 99 per cent 

 of the trees in Block No. I were found affected, and but four bugs 

 were found on one row of trees as compared with 223 on May 21st. 

 Had one only the observations made on June 1st to judge by, it would 

 have been impossible to associate Lygus j)ratensis with the injury. 



