90 



LOWER PTERYGOTA 



Pear Thrips (E nth rips pyri). — The pear thrips has been 

 a serious jjest in California, attacking beside pear a number 

 of the rehited fruits. Its attack is directed largely against 

 the bloom and the loss of fruit is serious. Contact sprays 

 are only partially effective, as the insect is protected so much 

 of the time within the parts of the bloom. 



Grass Thrips {Aphanaihrlps striata). — The grass thrips is 

 an extremely abundant species in the northeastern United 



Fig. 50.— The pear thrips {Euthrips pijri) : nymph or pupa. Much 

 enlarged. (After Moulton, Bur. Ent., U. S. Dept. Ag.) 



States, and has been reported as destructive to oats in 

 Canada. It attacks the upper part of the plant and its injury 

 shows, especially in the blasting of the heads of grass and 

 oats. In grass this is called "silver top," a condition of 

 whitening and withering of the upper stem and seed head 

 which is probably produced by other insects as well as thrips, 

 but which is no doubt in large measure to be credited to 

 these almost invisible little pests. 

 Another species is Thrijjs tahaci — known now as onion 



