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OUTLOOK ON PEAR PSYLIA 



H, E. Wave 

 Department of Entomology and Plant Pathology 



The pear psylla. Introduced into Connecticut about 1832, is a major 



insect pest of pears throughout the United States. Its role in pear 



culture is being reexamined by entomologists of the New York Agricultur- 

 al Experiment Station. 



In an article appearing in the March-May 195i| issue of Farm Research, 

 a quarterly bulletin published by the New York State Agricultural Exper- 

 iment Station, entomologists, A. L. Jones and E. H. Smith state that the 

 renewed interest in pear growing, especially the practice of increasing 

 vigor of the trees to obtain better yields, is expected to favor the 

 increase of such insects as the pear psylla. 



The pear psylla is reported to have developed resistance to insec- 

 ticides in the Pacific Northwest and there is a real likelihood that 

 this could occur in the East„ Studies by the New York State Agricul- 

 tural Experiment Station have shown that under some conditions psylla 

 may increase fire blight infections. 



In order to obtain more effective and lasting controls, they are 

 re-evaluating some earlier research on this pest, including the insects 

 biology. 



The psylla overwinter as adults under loose bark of pear trees. 

 They begin their activity earlier in the spring than most other pear 

 insects. During warm days in March and April they begin depositing 

 their eggs in crevices on fruit spurs and on the new leaf growth as it 

 emerges. 



Late season build up of psylla has been observed to occur in pear 

 plantings which results in a large overwintering population. This would 

 suggest the possible need for either a late season or a spring-dormant 

 spray treatment to assure low population levels early in the season. 



Dormant applications of 60-second petroleum oils have proven highly 

 effective against all stages of the psylla except eggs. Besides killing 

 adults and nymphs, petroleum oils also prevent egg laying by adults 

 until after green tissue appears „ Adults appear to be killed only when 

 spray deposits hit them directly whereas nymphs may be killed by the 

 oil deposits as they crawl over it to the emerging leaf tissue. While 

 oils are not effective ovicides against this pest, they do provide sat- 

 isfactory control by preventing oviposition of adults and by killing 

 newly emerged nymphs . 



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