A PILOT BLACK FLY (DIPTERA: SIMULIIDAE) CONTROL PROGRAM USING BACILLUS THURINGIENSIS VAR. ISRAELENSIS IN NEWFOUNDLAND

Abstract

AbstractA pilot black fly control program using Bacillus thuringiensis var. israelensis on a small stream system near St. John's, Newfoundland resulted in a 70% or greater population reduction of adult black flies from the previous year. The species present in the system were Prosimulium mixtum, Stegopterna mutata, Eusimulium vernum, Simulium tuberosum, S. venustum/verecundum complex, and S. vittatum. The formulation used was Teknar® flowable concentrate (Sandoz Inc.) rated at 600 ITU/mg which proved effective against the larval stages of all black fly species at a dose of 10 ppm for 1 min. The results indicated that this agent will be effective if applied at the appropriate locations and times. The 1-min dose was practical except in very cold water (0°–7 °C) where a 5-min or longer dose may be required. The unpredictable relief pattern of the northern streams resulted in a highly variable downstream carry for the B.t.i. Therefore application sites must be determined by a stream survey and not just from discharge characteristics.