EFFECT OF SOIL APPLICATIONS OF INSECTICIDES O 



Since the planted rows were well within the borders of the plots, 

 the entire crop in each row was harvested. With the exception of 

 the tomatoes, which were spaced 5 by 5 feet, the distance between 

 the rows was 30 inches (fig. 3). 



. . . '■:;::"■ :■'■- 



. ■ ■■--: -'-:. '-■' ' '■.'.■ ■ . . 



Figure 3. — Arrangement of vegetable plantings in a single plot. 



Small seeds were sown with a single-row garden planter, larger 

 seeds such as lima beans with a cylinder-type hand planter, which 

 spaced the seed at the desired distance. Plants for transplanting 

 were grown in flats in the greenhouse and then set out in the field 

 by hand. 



The plots were kept free of weeds during the winter months; 

 after the crops had been planted they were cultivated and weeded 

 at 2-week intervals. The crops were irrigated as uniformly as 

 possible by regulating the flow and irrigating the furrows in each 

 plot the same length of time (fig. 4). In 1949 the crops were irri- 

 gated on May 25 and June 29 ; in 1950 on March 30, May 18, and 

 July 6 ; and in 1951 on April 5 and June 8. 



Pest Control 



The fumigation with ethylene dibromide in 1949 did not prevent 

 wireworms from damaging some of the plots in 1950, and it was 

 necessary to fumigate the soil again on February 17, 1951, with 2 

 gallons of ethylene dibromide per acre. 



To insure a crop it was necessary to apply an insecticide or a 

 fungicide periodically to control other plant pests. To lessen the 



