METHIOCARB AS A BIRD REPELLENT FOR MATURE SWEET CORN

Sweet corn in Ohio is an important high-value truck crop (74,000 acres in 1974--Ohio Crop Rep. Serv., 1975) that is especially vulnerable to blackbird damage. For this reason, a chemical treatment that would repel birds from sweet corn would be advantageous. A candidate chemical for this use is methiocarb [3,5-dimethyl-4-(Methylthio)-phenyl methylcarbamate = Mesurol (product of Chemagro, Division of Mobay Chemical Corporation)]. In addition to insecticidal, acaricidal, and molluscieidal properties (Hermann and Kolbe, 1971:286), Schafer and Brunton (1971) established in cage tests that methiocarb was a promising bird repellent because low concentrations (\u3c0.16%) would repel birds from treated rice seed. The chemical apparently reinforces a bad taste by producing a conditioned aver- sion to its intoxicating effects (Rogers, 1974). When applied to corn seed prior to planting, methiocarb treatments reduced blackbird damage to sprouts (Hermann and Kolbe, 1971; Stickley and Guarino, 1972; Ingram, et al., 1974; Linehan, et al., 1975; Stickley and Ingram, 1975). However, Mitchell, et al. (1975) did not show significant protection, and Linehan, et al, (1975) showed some phytotoxicity in cold, wet growing conditions. Methiocarb treatments also have shown indications of efficacy when applied to mature grain crops [rice at 10.0 and 3.2 lb (active material) per acre (DeHaven, et al., 1971), sorghum at 2.0 lb (active material) per acre (Mott, et al., 1974), and sorghum at 1.6 lb (active material) per acre (Mott and Lewis, 1975)]. Because of these results, we conducted a screening experiment in 1975 to determine the feasibility of methiocarb treatments for repelling blackbirds from ripening sweet corn