Results of Use of Electric Light Traps to Control Insects in the 

 Home Vegetable Garden. 4 



Experiments were conducted in both 1958 and 1959. The season of 1958 was cool and 

 wet; the total rainfall for May, June, July, and August was 29.41" or 13.95" above the 

 normal of 15.46". In 1959 the rainfall was 6.11" below normal and the temperatures were 

 normal or above. The experiment was set up in three blocks in 1958 and in four in 1959. 

 Each block contained four 50' x 60' plots. Each plot contained six vegetables (beans, 

 cabbage, cucumbers, potatoes, sweet corn (an early and a late planting), and tomatoes.) 

 In each block one plot was protected by a trap containing a single 15-watt BL fluorescent 

 lamp, a second by a trap containing one 15-watt BL and one 15-watt green fluorescent 

 lamp, and a third by a trap containing three 15-watt BL lamps. The fourth plot in each 

 block was unlighted and served as a check. The lighted and unlighted plots in each block 

 were chosen at random. The plots were placed Z30 feet apart in a 14-acre field in 1958 

 and a 16-acre one in 1959. No insecticides or fungicides were used on any of the plants 

 in the experiment or in any of the adjacent fields. 



Beans : The Mexican bean beetle was scarce in both 1958 and 1959 and rather evenly 

 distributed in both the lighted and unlighted plots. The population of potato leafhoppers 

 and the incidence of hopperburn were light but were heavier, but not significantly so, in 

 the lighted than in the unlighted plots. Hopperburn was significantly heavier in the un- 

 lighted checks in 1959 than it was in the plots protected by the three BL lamps. 



Cabbage: In 1958 imported cabbageworms and diamondback moth larvae were 

 scarce and ■were evenly distributed throughout all plots. Damage •was confined to outer 

 leaves and no commercial damage occurred. The cabbage looper damage was light and 

 rather uniform. In 1959 the imported cabbageworm population was very high and all 

 plants were damaged severely. 



Cucumbers : The yields for the 2 years are shown in the following table: 



Average Yield in Weight and Numbers of Cucumbers 

 Six Inches or More in Length 



Treatments 



1958 (Av. 3 Rep.) 



Weight (lbs.) Number 



1959 (Av. 4 Rep.) 



Weight (lbs.) Number 



Unlighted check 



70.9 



154 



1 15-WBL lamp 



118.8 



293 



1 15-W BL & 1 15-W green 



183.8 



388 



3 15-W BL 



328.4 



665 



89.3 



212 



116.2 



280 



98.2 



232 



147.0 



331 



In 1958 the yields were significantly better in all the treatments than in the checks. 

 In 1959 the yields in the plots protected by the three 15-watt BL lamps were significantly 

 higher than in the check plots. In 1958 the main reason for the differences in the yields 

 seemed to be due to the number of plants that died from cucurbit wilt. In 1959, although 

 there were 2x as many striped and 6x as many spotted cucumber beetles captured at 

 the traps as in 1958, only half as many plants died from cucurbit wilt. Since the same 

 number of plants survived until the last of August and the amount of feeding by the 

 beetles was practically the same in both years in the plots protected by the three 15-watt 

 BL lamps, it would seem that the lower yields obtained in 1959 can be attributed to the 

 dry weather. 



4 See footnote 3. 



52 



