75 



TJie Littleton Experiment. — Mr. Homer Richards, a truck gardener and orchardist 

 living in Littleton, offered the use of a one-acre field of winter squashes and, in 

 addition, his assistance in the application of the sprays. The field contained 

 twenty rows planted fifteen feet apart, and twentj'-five hills six feet apart in each 

 row. Plots were marked off as follows : — 



Four applications were made: on July 5, July 12, 

 July 19, and Jul.y 26. Compressed air sprayers of 

 three-gallon capacitj^ were used for the first three 

 applications. Each was fitted \yith. a short spraA' rod 

 and a 45° angle disc nozzle, pictured in figure 1. All 

 portions of the plants were thoroughly sprayed, par- 

 ticular attention being paid to the base of the stem. 

 The fourth application was made with a power sprayer 

 and one lead of hose bearing the short spray rod and 

 angle nozzle. A pressure of 100 to 125 pounds per 

 sciuare inch was maintained. 



Examinations to check the progress of the infesta- 

 tion and the effect of the treatment were made by 

 the writer on each trip to Littleton. On July 13, a 

 count of eggs on about twenty-five plants in each treatment gave the following 

 results : — 



FiQ. 1. 45° Angle-disc Noz2le 

 Used in the Experiments. 



The difference in number of eggs exhibited by the check and treated plots is 

 attributed to the mechanical effect of the spraj- in knocking some eggs from the 

 plants. The writer has noticed frequently that while some eggs are firmly attached 

 to the plants, others may be dislodged at a touch. The difference exhibited between 

 the lead arsenate treatment and the Black-leaf "40" is attributed to a possible 

 slight repellent effect of the nicotine sprays, the odor of which can be detected on 

 the vines for about twenty-four hours following their application. 



The effectiveness of the treatments was determined by counts of the number of 

 borers and number of plants in treated and check plots. The final count was made 

 on August 13 and 14, at which time the oldest larvae were readj'' to leave the vines, 

 and the youngest ones were large enough to make their presence knoA\ai. Every 

 plant in the experimental field was carefully examined for borer injury, and the 

 number of plants and number of borers in each hill recorded. The detailed results 

 of this count are given in Table V. A summary of these counts, translated into 

 borers per thousand plants, is also given. 



