Mortality Effected by Pesticide Residues on Peas, Summer 1977

The peas were planted in 5x20-ft, 8-row beds with 7-inch interrow spacing. The treatments were applied to the beds on June 17, about 14 days before harvest, by using a rear-mounted boom sprayer fitted to a JD 1520 tractor traveling at 2.75 mph. An air pressure of 60 psi forced 80 gpm through D2-25 TEEJET nozzles mounted 11 inches apart on the spray boom. The boom height was adjusted to provide maximum coverage of the foliage. There were 3 replicates of each treatment. Immediately after treatment and 2, 4, 6, and 8 days later, bouquets were prepared from foliage selected at random from the middle of each bed. Each bouquet, consisting of five 12-inch-long plant terminals, was placed into a 1/2-gal polyethylene container together with 5 each of second- and fourth-stage larvae. Then the containers were closed with a piece of cheesecloth and held in the greenhouse in natural light and at temperatures of 65-75°F. The larvae in each container were examined every day for 5 days to determine both mortality and feeding damage.