ANNUAL REPORT, 1943-14 37 



larvae and early varieties were severely damaged. Many varieties of flowers 

 were attacked, and some commercial plantings of dahlias were ruined. 



In the middle Connecticut Valley moths were emerging by May 24, and the 

 larvae began to appear by June 10. In the experimental plots insecticides were 

 applied on June 11, 16, 21, 25, and 30. Precipitation was comparatively light 

 during this period and caused no serious interference with any application. 



Preharvest examination of the experimental plots for early evidence of attack 

 showed that 85 percent of the plants sprayed with derris, 89 percent of the plants 

 dusted with fixed nicotine, 55 percent of the plants given fixed nicotine sprays, 

 but only 15 percent of the unsprayed plants were free from infestation. Sub- 

 sequent counts of borer population showed an average of 53^ borers per plant 

 in the check plots, 2^ in the fixed nicotine sprayed plots, 2 in dusted plots, and 

 1 J^ in the plots sprayed with derris. 



In the dusted plots 95 percent of the corn harvested was free from borers, and 

 94 percent of the total yield was of marketable grade. In the plots sprayed with 

 derris, 91 percent of the ears were clean and 89 percent of marketable grade. A 

 schedule of fixed nicotine spray at 3 pounds to 100 gallons dosage gave 90 percent 

 of the yield free from injury and 86 percent of marketable grade. A 2-pound 

 dosage allowed 89 percent borer free ears, with 85 percent of the total yield of 

 marketable grade. In the unsprayed check plots, while 64 percent of the crop 

 harvested was borer free, only 55 percent ot the total yield was fit for market. 



In late pickings the contrast between treated and check plots was greater. 

 Only 35 percent of the last picking in the check plots was of marketable grade. 



Introduction of Parasites of Oriental Fruit Moth in Peach Orchards. (A. I. 



Bourne.) The fruit buds of peaches were practically all destroyed by the un- 

 usually low temperatures of the winter (1942-43) in Massachusetts, and some 

 injury to the wood also resulted. There was practically no peach crop in this 

 State or throughout most of the northern peach-growing area. Only two growers 

 requested Macrocentrus parasites of the oriental fruit moth and these orders were 

 filled by purchase from the Connecticut Agricultural Experiment Station through 

 the cooperation of Doctors Friend and Garman. A few colonies for experimental 

 release were supplied bj' Dr. H. W. Allen of the U. S. Bureau of Entomology and 

 Plant Quarantine Laboratory, Moorestown, N. J. 



Apple Maggot Emergence. (W. D. Whitcomb.) In 1943 the number of apple 

 maggot flies was generally below normal but many of the flies remained active 

 and laid eggs over a long period, which resulted in moderate infestation in many 

 commercial orchards and heavy infestation in home orchards. 



The emergence of flies in the cages at Waltham was the lowest since the cages 

 have been in operation, being only 9 percent of the possible total and 18 percent 

 of the expected total. 



Emergence of Apple Maggot Flies, 1943, Waltham, Mass. 



Control of Common Red Spider Mite on Greenhouse Plants. (W. D. Whit- 

 comb, Wm. Garland, and Wm. E. Tomlinson, Jr., Waltham.) Life history 

 studies of the common red spider mite at constant temperatures were continued 



