April, '13] HASEMAN: PEACH STOP BACK 237 



PEACH "STOP BACK" AND TARNISHED PLANT BUG 



{Lygus pratensis Linn.) 

 By Leonard Haseman, Department of Entomology, University of Missouri 



For many years the nurserymen of Missouri as well as those of 

 other states have been confronted with injury to peach and pear buds 

 in the early spring. This injury has been laid to various causes. 

 Some attribute it to the work of thrips, others to mites and in some 

 cases it has been supposed to be due to soil conditions. A number 

 of papers during the past year have appeared in which the relation 

 of the tarnished plant bug to this injury has been carefully discussed. 

 In the writings of some of the earlier entomologists we find brief 

 discussions of the importance of the tarnished plant bug with reference 

 to the destruction of buds and to the injury it does to fruit and plants 

 in general. It is not strange, therefore, that we should suspect this 

 insect and attribute to it at least a part of the injury to peach and pear 

 buds. 



For the past two years the writer has been following the injury 

 commonly spoken of as "stop back" of peach here in Missouri and 

 finds that the tarnished plant bug is responsible for this injury. The 

 injury is worse some seasons than others and seems to be worse in 

 certain parts of fields. Invariably it is the more thrifty growing nursery 

 stock which suffers most and this is usually in the damper parts of 

 the nursery blocks and where the soil is richest. During the past 

 spring this injury was probably as noticeable in certain sections of 

 Missouri as it has even been known to be in this state. Some seasons 

 the injury begins to appear soon after the dormant buds in budded 

 peach stock begin to push out but fortunately the past summer it did 

 not occur until the first week in June after the young growth had 

 advanced from eighteen inches to two feet and therefore was not 

 especially destructive, though in some portions of the infested blocks 

 nearly all of the growing buds were killed. This injury occurs all of a 

 sudden and the agent of destruction seemingly disappears from the 

 nursery almost as suddenly. 



The study of this pest is being carried on at the Experiment Station 

 and in one of the nurseries of central Missouri. The nurseryman 

 notified the writer on June 7, three or four days after the first severe 

 signs of the pest appeared, and on arriving at the nursery it was found 

 that but few bugs still remained in the nursery, but on visiting ad- 

 joining fields of clover, timothy and weeds it was found that they were 

 present in great swarms, especially in clover where they were at work 



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