426 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



possible to get the spray on the thrips, that there was no trouble in 

 killing them. The difficulty lay in being able to get . the spray into 

 the blossoms and later under the husks of the little peaches. 



Various types of nozzle were used and as high pressure as was possible 

 to obtain with a power sprayer was tried in an effort to get the spray 

 where the thrips were protected by the blossoms or the husks. In all 

 the work the fact was apparent that the protection of the stamen bars 

 and the pistil of the peach blossom was such that it was almost impossible 

 to reach the insects with the spray and after the peaches had formed the 

 same difficulty was experienced in getting the spray beneath the dried- 

 up blossom or husk. Thus, after recommendations had been made 

 regarding the way this insect might be controlled, spraying was stopped 

 in orchards of the community because of failure to get the desired results. 



Dusting 



Sam.ples of Nicodust manufactured by the California Walnut Growers 

 Exchange were also used in some experiments. Regular strength of this 

 material as well as double strength ; also a Nicodust material made from 

 nicotine and sulphur, were all tried but none of them were successful. 

 Blossoms that were thoroughly coated with these dust materials were 

 brought into the laboratory and in twenty-four hours' time it was found 

 that the thrips were apparently just as lively as before the material was 

 applied. A few thrips seemed to be killed where the dust came in actual 

 contact with them, but where it did not, there seemed to be no effect from 

 fumes and thrips inside of blossoms where the stamen bars and 

 pistil -were heavily coated with this material were as lively as ever. 



In 1921 the dusting experiments were repeated although it was not 

 possible during this season to find as bad an infestation as most of the 

 orchards had the previous season. The same negative results were 

 secured in 1921 as in 1920. 



Injury 



The characteristic injur}^ done to peaches by thrips assumes a number 

 of different form.s which seem to be influenced somewhat by the variety. 



In the case of Phillips Cling variety for example, a very common type 

 of injury is a little conical shaped swelling on the surface of the fruit. 

 In the case of the Tuskena variety the injury that is more commonly 

 noticed consists of a pitting or dimpling of the surface of the fruit. In 

 other cases where the fuzz has been removed entirely by the thrips in 

 feeding, the skin will be colored a deep red and will be smooth like the 



