Laboratory and Field Trials Using Altosid® Insect Growth Regulator Against Black Flies (Diptera: Simuliidae) of Newfoundland, Canada

Abstract

Altosid® (methoprene), an insect growth regulator, was used in laboratory and field trials to assess its potential as a control agent for black flies (Simuliidae). Results of laboratory trials showed that (I) Altosid caused pupal rather than larval mortality in Simulium venustum/verecundum ; (2) of the several formulations tested, Altosid microencapsulated PS10 gave the best results, completely inhibiting eclosion in S. venustum/verecundum at a dosage rate of 20 μg/l × 30 min; (3) exposure of S. vittatum larvae to Altosid PS10 at dosage rates up to 20 μg/l × 30 min did not affect fecundity in adults; and (4) “pulse” (i.e., 30-min) dosing with Altosid was a more efficient means of inducing mortality than was continuous dosing. Field trials were carried out using single applications of Altosid PS10 or emulsifiable concentrate at 12. 25, or 50 μg/l × 30 min in 5 local streams. Altosid application produced a sharp drop in pupal emergence 6–7 days after dosing; the emergence rate subsequently returned gradually to predose levels. 1n the 1978 field program, Altosid PS10 applied at 25 or 50 μg/l × 30 min at 14-day intervals to 3 streams inflicted 93.8–99.1 % mortality in Simulium spp. and was also effective against Prosimulium mixtum .