1985 Volume 36 Issue 4 Pages 309-313
Two insect growth regulators (IGRs), diflubenzuron and methoprene, were tested against laboratory-reared larvae of Chironomus yoshimatsui. A 25% WP formulation of diflubenzuron resulted in high larval and pupal mortality when 3,7,and 10-day-old larvae were exposed to the chemical solution at a concentration from 0.312 to 2.5ppb for 15,10,and 8 days, respectively. During the same exposure periods to a 10% SR formulation of methoprene in the laboratory, the larvae and pupae suffered from insignificant mortality but the adult emergence remained low at the same concentration prepared. A drip application of diflubenzuron in a river at 1ppm concentration maintained for 60min resulted in excellent larval control with no adult emergence as measured by using adhesive tapes; however, methoprene at same rate of application to the river produced lesser control of the midge.
