810 Popular Editions of Station Bulletins of the 



In 1910, when the loss from the thrips was 



Amount of greatest, pear growers in the region about Ger- 



injury. mantown found their Kieffer crops reduced from 



one-third to nine-tenths or even more. The ex- 

 cessive damage during this season was probably due to the early 

 and sudden arrival of warm weather which favored the insects 

 and also brought the pears into bud and bloom when the pests 

 were most abundant. The union of these two factors exposed 

 practically all Kieffers and some other varieties to the attacks 

 of countless hordes of the thrips at the most critical time. In 

 1911, the damage to Kieffers, though general in some orchards 

 and severe in scattered spots in other orchards, was not nearly as 

 great as in 1910; while Bartletts and Clapp Favorites, the other 

 varieties most grown in the section, were not seriously injured. 

 Beurre Bosc, Beurre Anjou, Vermont Beauty, Dana ITovey, 

 Rhode Island, Clairgeau and Beauty of Wakefield were badly 

 affected; but these varieties are not generally grown so the loss 

 on them was not great. 



The mature thrips is a very minute insect, only 

 Adult insect, one-twentieth of an inch long. It is dark brown 



in color, appearing almost black on casual view; 

 and bears four peculiar, long, narrow, feathery wings which gave 

 the thrips its old name, " fringe-wings." The wings are simple and 

 each consists merely of a single strong rib bordered by closely set, 

 long hairs. 



These adults come from resting cells in the soil, where they 

 have spent the winter. The date of emergence varies with the 

 season, but is apparently timed to precede by a few days the 

 swelling and opening of the pear buds. Growers, where the 

 insect is suspected or wliere pear buds hai^^e blighted from 

 unknown causes, should watch their trees carefully from the 

 middle of April on, and if they find them spotted with tiny dark 

 flies, should prepare for immediate, vigorous action. 



In 1911 the adults were most active and destructive from 



April 28 to May 11. As soon as they come from the ground 



they seek the trees whose buds are nearest ready to open, and 



work their way between the spreading tips into the centers of 



