360 Eepokt of the Department of Entomology of the 



preparation to 100 gallons of water to which were added 3 gallons 

 of stock emulsion; and (3) Black Leaf 40, % pint to 100 gallons 

 of water and 5 pounds of soap. The accompanying chart shows 

 the arrangements of the plats and dates of the applications of the 

 sprays. The treatments during the period of April 28 to May 1 

 were made for the purpose of protecting the opening blossom buds 

 and blossom clusters from the adult thrips, while the sprayings 

 from May 10 to 12 were intended to destroy the young larva on 

 the fruits and foliage. 



DETAILS OF SPEAYING AND RESULTS ON THEIPS. 



The first treatment of Plat B was made on April 28, when the 

 most advanced Kieffer buds were quite compact, and at least three 

 days before any blossom clusters separated at the tips. The ma- 

 jority of the thrips were on the outsides of the buds. Quite a 

 few of them were working their way into the ends of the buds, 

 although most of these were still in more or less exposed positions. 

 The nicotine extract with soap was used liberally and the trees 

 were thoroughly drenched. The treatment was, in the main, very 

 effective, killing all of the insects which were wetted with the 

 spray. With the exception of the comparatively few thrips buried 

 deeply in the substance of the buds, the sprayed trees were during 

 the remainder of the day noticeably freer of the insects than the 

 untreated portions of the orchard. While many thrips escaped 

 treatment the effect of the day's work was to encourage the belief 

 that by thorough and repeated spraying the thrips could be re- 

 duced to unimportant numbers. 



On April 29 the buds were in a condition of growth that fav- 

 ored deeper penetration by the insects and a much larger per- 

 centage of the thrips on the trees were within the buds feeding 

 apparently about the pedicels of the rudimentary flowers. Sap, 

 too, was flowing from injured blossom clusters. During the first 

 application of this day's spraying large numbers of the thrips were 

 killed but it was practically impossible to reduce materially the 

 numbers of those well within the compact blossom clusters. 



