48 MASS. EXPERIMENT STATION BULLETIN 315 



appeared to exert a considerable repellent effect in addition to their direct killing 

 action. The sprays were slightly superior to the dusts. The pyrethrum dust was 

 effective for a short time after application but appeared to have very little residual 

 effect. No opportunity was allowed for the development of any aphid or leaf- 

 hopper infestation in the rotenone or pyrethrum plots, but in order to control 

 incipient attacks of aphids nicotine sulfate had to be added in two applications 

 of the Bordeaux mixture in those plots where Bordeaux alone had been applied. 



Excellent yields were secured in all the plots and particularly in those where 

 rotenone compounds had been applied. The yield record of the different plots 

 is as follows: 



Material Yield 



(Bushels per Acre) 



Cubor spray (rotenone) 647 . 99 



Cubor dust (rotenone) 579. 



Ku-ba-tox spray (rotenone) 573 . 75 



Ku-ba-tox dust (rotenone) 601 .38 



Pyrethrum dust 489 . 57 



Calcium arsenate-arsenite mixture 519. 12 



Bordeaux mixture 560 . 3 



The high yields in the rotenone-treated plots confirmed the superior appearance 

 of the plants in those plots throughout the season, and indicate the correlation 

 between heavy yields and the protection of the growing plants from diseases 

 and insect pests. 



Value of Electric Light Traps against Orchard Insect Pests. (A. I. Bourne.) 

 During the past summer, through the cooperation of the New England Rural 

 Electrification Committee and the Western Counties Light and Power Company, 

 this department began a series of tests with electric light traps at the Bay Road 

 Fruit Farm orchards in South Amherst. 



Five bulb and pan and five electrocutor traps were installed in parallel rows. 

 Electric power was supplied from wires running from a take-off from the main 

 power line at the edge of the orchard. On the outer pole was placed an automatic 

 time clock, fuse-box, and cut-out switch, and on the pole in the orchard was placed 

 a recording thermograph. The electrocutor traps consisted of a 75-watt bulb 

 suspended inside of a screen charged with about 1100 volts from a transformer 

 in the top of the trap. Beneath the circular screen was suspended a wire basket to 

 catch the insects which were electrocuted while flying through the charged screen 

 toward the light. The bulb and pan traps consisted merely of a 75-watt bulb 

 suspended over a pan of water, the surface of the water acting as a reflector to 

 which the insects were attracted and drowned. 



The lights were operated from June 18 until August 28, under control of an 

 automatic time clock in series with the power line to the traps. The lights were 

 on from one-half hour before sunset until about one-half hour before sunrise, 

 corresponding to the flight period of the insects present in the orchard. Lights 

 were turned off on rainy nights when insect flight was very slight. Each day the 

 insect catch of the night before was counted and identified. A total of 42,857 

 insects was counted and identified, of which 1,498 were beneficial species. Orchard 

 pests were counted as follows: codling moth, 321; apple tent caterpillar, 684; 

 forest tent caterpillar, 52; bud moth, 43; cherry leaf roller, 35; plum curculio, 1; 

 and apple maggot, 1. These numbers are undoubtedly only indicative of the 

 actual numbers caught in the traps as the electrocutor traps completely burned 

 the insects entering them. 



