Wildlife Damage Management, Internet Center for


Date of this Version

November 1976


On August 26, 1976 Avitrol FC Corn Chops-99S (AFCC-99S) was federally registered (EPA Registration No. 11649-15) for use in protecting ripening sunflowers from damage by blackbirds. The registration was the culmination of seven years of effort by the U.S. Fish and Wildlife Service to extend the use of AFCC-99, which was registered for use against blackbirds in field corn in April 1972. Ripening sunflowers are probably more intensively damaged by blackbirds in the U.S. than any other crop. In a 1972 survey in 469 randomly selected sunflower fields in North Dakota and Minnesota, Stone (1973) found that 9.7% of heads examined had been damaged by birds. Initial small-scale tests with AFCC-99S for protecting sunflowers were conducted in North Dakota in 1967. R.V. Hansen and W.K. Pfeifer (unpublished reports of Division of Wildlife Services, North Dakota) reported satisfactory to excellent results by spreading AFCC-99S in disked strips between standing sunflowers in Rolette County in 1967, in Ransom County in 1968 to 1970, in Cass and Ransom counties in 1971, and in Cass County in 1972. In 1973, the first large-scale tests where AFCC-99S baits were broadcast within ripening sunflower fields were conducted by personnel of the Denver Wildlife Research Center and cooperators. The purpose of this paper is to summarize the data from tests in 1973 and 1974 that largely formed the basis for the registration. Greater detail is presented in the unpublished reports of these studies (Guarino 1974; Besser and Cummings 1975).