36 MASS. EXPERIMENT STATION BULLETIN 417 



each reduction of 50 percent in concentration, the effectiveness was reduced 

 about 7 percent. Semesan at the rate of 3 ounces in 10 gallons of water gave 86 

 percent protection in two applications. Tar paper discs when applied care- 

 fully gave perfect commercial control on both cabbage and cauliflower, and it 

 was demonstrated that this is the most practical treatment in the home garden. 

 The results of these studies have been summarized and published in Bulletin 

 412. 



Control of Squash Vine Borer. (W. D. Whitcomb, Waltham.) The field in- 

 festation of the squash vine borer at Waltham in 1943 was moderately severe, 

 averaging 4 borer injuries per vine in Blue Hubbard and 2 per vine in Buttercup. 

 The Buttercup is a relatively small-stemmed variety and appeared to be less 

 attractive to the borer, but the borer injury was more destructive to the vine than 

 to the larger-stemmed Blue Hubbard. 



Four applications at weekly intervals during July of nicotine sulfate 1-250, 

 and nicotine sulfate 1-500, plus Volck 1 percent, gave good control and reduced 

 borer injury 72 and 80 percent. The addition of bordeaux mixture 2-2-50 to 

 these sprat's failed to cause significant differences either in borer control or yield. 



The addition of 33 percent cryolite to a nicotine-copper dust increased the 

 control 25 percent and gave satisfactory protection. 



The Value of Control Measures to Supplement the Standard Spray Program 

 for Apple Pests in Massachusetts. (A. I. Bourne, in cooperation with the De- 

 partments of Pomology and Plant Pathology.) All of the early-season sprays 

 were applied within a temperature range of 57° to 67° and with low to moderate 

 humidity. In the subsequent cover sprays the temperature range was 66° to 

 80° and humidity moderate. No evidence of spraj' injury was noted throughout 

 the entire season. 



The season proved to be very favorable for most insects and especially so for 

 scab. Foliage infection was evident very generally in all blocks, although the 

 fruit was fairly well protected, Unsprayed checks showed 96 percent scabby 

 fruit. 



Examination of the fruit at harvest showed 23 percent codling moth and 17 

 percent curculio damage and 5 percent scab on the plot which received the stan- 

 dard schedule. Unsprayed trees showed 72 percent codling moth, 66 percent 

 curculio, and 96 percent scab. 



A special application of fixed nicotine between the 2d and 3d cover sprays 

 reduced codling moth damage to 13 percent, a reduction of nearly 44 percent 

 from that in the standard schedule. 



The nicotine in DX base, in a modified schedule with reduced strengths of 

 lead arsenate, held codling moth damage to 5 percent, a 78 percent reduction 

 from the standard schedule, with approximately the same protection against 

 scab. 



One application of a fixed nicotine spray replacing lead arsenate in the 4th 

 cover spray reduced codling moth injury to 7 percent; and when an additional 

 application of fixed nicotine followed in mid-August, injury was cut to 5 percent, 

 a reduction of 78 percent from the standard schedule and 92 percent from the 

 unsprayed checks. 



Insecticides for the Control of European Corn Borer. (A. I . Bourne.) Through- 

 out practically all the Northeastern States, European corn borer developed one 

 of the heaviest infestations and caused the greatest amount of damage in recent 

 years. Relaxation of fall clean-up programs did much to aggravate the situation. 

 Damage was not confined to corn. Potatoes were heavily infested by first-brood 



