Black Fly Control and Suppression of Leucocytozoonosis in Turkeys

A large-scale Simulium control program using a wettable powder formulation of Vectob8c~, Bacillus thuringicnsis val". israelensis de Bnrjnc. was conducted in coastal South Carolina to suppress Lcucocytozoon smith; (Lnveran and Lucet) transmission in turkeys. All pennanent streams within a 7.2 km radius of 8 commercial turkey fnrm in the Coast.al Plains were treated fit 1 to 2 wk intervals during the summer and carly foil of 19B I and 1982. LeucocytozoOTl smithi infection levels and pnrnsitemias in sentinel Bnd commercial lurke)' flocks were t.he major criteria used in cvaluuling the results. Erratic and high levels of precipitation during 1981 prevented adequate treatment. of the streams. A more frequent. treatment schedule was maintained in 1982 resulting in substantial decreases in parasitemia and no losses or observable pathology in either the sentinel or commercial flocks. In 1982, as in previous years, infection levels were higher in ranged turkeys than in housed birds. During 1982, I... smilhi gllmctocytc levcls were much higher in housed turkel's than those observed in previous years. This reflected greater numbers of Simulium vectors entering the houses to feed; however. the reasons for this arc uncleal".