!N"ew York Agricultural Experiment Station. 349 



pared with the winged thrips it is less active and less destructive 

 on the whole to the trees, but it is nevertheless capable of causing 

 quite a little damage under certain conditions. On pears the 

 principal injuries by the larvae are to the young leaves. The pro- 

 duction of the young is unfortunately most abundant on those 

 trees which suffer the most from the adult thrips because oviposi- 

 tion largely accompanies feeding at the time when the trees are 

 most severely injured. The destruction of a considerable per- 

 centage of blossom and leaf buds by the adults is a great shock to 

 the tree, and because of its weakened state it is usually slow in 

 recovering its normal conditions of foliage. The new growth 

 from the weak leaf clusters and the adventitious buds is, likely 

 to be feeble and small in quantity, and not infrequently young 

 leaves in the opening buds or before they have unrolled are 

 killed by the young thrips, or are so injured that on ex- 

 panding they are stunted and ill-shapen. This accumulated 

 injury by the larvae further retards the recuperation of the 

 tree and may result in premature dropping of the young pears or 

 in the death of fruit spurs. With the dropping of the petals the 

 calyx basins of the fruits become less and less attractive to the 

 larvse and eventually most of them find their way to the foliage. 

 The folds or rolled edges of unfolding leaves, particularly of the 

 terminal growth, are especially sought by them. Globules of sap 

 accumulate from wounds as a result of the feeding punctures and 

 the young leaves become blackened along the margins and cup- 

 shaped or otherwise distorted in appearance. On cherries, espe- 

 cially of the sweet varieties, the larvse collect in large numbers 

 under loosened calyces of the young fruits and cause abrasions 

 in the surface of the skin. During the past season these injuries 

 were superficial and did not appreciably affect the appearance of 

 the fruit. The larvse also feed on the foliage and seem to prefer 

 to work on the under surfaces of the leaves, principally along the 

 main rib or in the angles formed by the secondary veins. Light- 

 colored blotches with brownish centers develop which become quite 

 conspicuous at the time the calyces are dropping, for hardly a leaf 



