70 



and in orchards were so badly infested that growth was seriously 

 checked and the trees in many cases permanently injured. Two nurs- 

 erymen report that their losses would aggregate $5,000 each. Apple 

 and sweet cherry stocks suffered the most; sour cherries beside badly 

 injured sweet varieties were not touched; some" varieties of apples 

 were damaged more than others, and the infestation was worst in 

 certain spots in some nurseries. But the most surprising and 

 destructive work was wrought by these little pests in many large 

 bearing apple orchards in western New York. Reports reached us 

 in June that large prospective crops of apples were being ruined by 

 plant-lice. So unusual is it for these insects to appear in sufficient 

 numbers to injure the fruit that we could hardly believe our eyes 

 when we visited some infested orchards. The young fruits were 

 swarming with the lice, which had stunted their growth and given the 

 fruits a misshapen, knotty appearance, as shown in PL II. One large 

 apple buyer stated in the autumn that it was very difficult to pack 

 good stock in the infested orchards. One grower reports that he 

 thinks his crop was reduced one-half by the lice. 



We believe that certain weather conditions and a scarcity of their 

 natural enemies were potent factors in causing this unusual outbreak 

 of plant-liee. We found but comparatively few of their enemies, 

 like the ladybird beetles and their grubs, the lacewing flies, and the 

 Syrphus flies, in the infested orchards in June. Later in the season 

 some of their enemies "rose to the occasion" and reaped a rich 

 harvest, often cleaning trees completely of the lice. It is possible 

 that the excessive wet season of 1902, or perhaps an extreme dry 

 period in the spring, may have been unfavorable for the development 

 of these natural enemies and favorable for the plant-lice. We have 

 but little definite knowledge of just what weather conditions cause 

 the "ups and downs" of insect life. Can not this Association devise 

 some scheme for filling in this much-needed chapter in our insect-life 

 book? 



We found both the rosy apple aphis (Aphis sorbi) and the apple 

 leaf aphis (Aphis pomi) in the infested orchards in June, but it is 

 quite probable that Fitch's apple aphis (Aphis fitchii) was also abun- 

 dant on the buds earlier in the season. Owners of large orchards 

 made little or no effort to check the lice, but many young orchards 

 and hundreds of acres of nursery stock were treated several times 

 with the usual oil and soap mixtures with good success where the 

 work was thoroughly done. We can offer no definite predictions for 

 1904, but it is very doubtful if plant-lice are again as numerous in 

 several years in New York. 



THE PEAR PSYLLA. 



The summer broods of this serious pest swarmed over most New 

 York pear orchards last season, and much damage was done; even 



