Table IV, — Squash Vine Eggs at Littleton, July 13, 1923. 



Tkeatmext. 



Check 



Black Leaf " 40 ". 1-500 

 Lead Arsenate, 2.5—50 

 Black Leaf '"40 ", 1-100 



Eggs per Plant. 



1 04 

 77 

 94 

 80 



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

 is attributed to the mechanical etfect of the spray 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 ready 

 to leave the vines, and the youngest ones were large enough to make their 

 presence known. Every plant in the experimental field Avas 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. 



Table V. — Effectiveness of Treatments, Littleton, 1923. 



The Amherst Experiment. — The experimental field at the Massachusetts 

 Agricultural Experiment Station contained twenty-eight rows, twelve feet 

 apart, with nine hills, eight feet apart in each row. Each treatment was 

 applied to each of three separate plots, and each treated plot was flanked by 

 a check plot with which its infestation was compared. The plan was as 

 follows : — 



Rows. Treatment. Rows. Treatment. 



Four applications were made : — on July 7, July 17, July 23, and August 2. 

 The first application was made with a compressed air sprayer, and the other 

 three with a power outfit. Before the last application it was found necessary to 

 move some runners from the path of the spray rig as it passed between the 

 rows. 



On July 24, a count of eggs and larvae present in the different plots gave 

 the following results : — 



