Field Tests of a Copper-based Fungicide as a Bird Repellent Rice Seed Treatment

In east Texas, bird damage to sprouting rice was reduced in two of seven study plots when rice seed was treated with the fungicide Kocide® SD at the maximum label rate (8 fluid oz/100 1b seed). Foraging rates of male redwinged blackbirds (Agelaius phoeniceus) in treated plots were lower (P = 0.02) than were those in control plots. We suspect that the copper in Kocide SD produces physiological effects that suppress feeding activity that results in reduced losses in some cases. Because it is registered for use on rice and is relatively inexpensive, Kocide SD may be a useful component of some bird damage reduction strategies. Proc. 16th Vertebr. Pest Conf. (W.S. Halverson& A.C. Crabb, Eds.) Published at Univ. of Calif., Davis. 1994. INTRODUCTION Bird damage to newly planted rice costs growers in southwestern Louisiana and eastern Texas millions of dollars annually (Wilson et al. 1989, Decker et al. 1990). Methiocarb is an effective bird repellent (Holler et al. 1985), but it is unavailable to growers because it is not EPA-registered. Lethal control using rice bait treated with DRC-1339 (3-chloro-4-methylaniline HC1) may reduce local bird populations, but its effectiveness as a general damage reduction tool remains to be demonstrated (Glahn and Wilson 1992). Alternatively, bird-resistant, nontoxic seed coatings have proven effective in various cage and small enclosure trials (Daneke and Decker 1988, Avery and Decker 1992, Avery et al. 1993). In particular, Kocide® SD, a seed treatment fungicide currently registered for use on rice, has proven effective as a bird repellent in cage feeding trials and flight pen tests (Avery and Decker 1991). This multi-year study was performed to evaluate the field efficacy of Kocide SD, applied at the current fungicide label rate, as a deterrent to birds feeding on newly planted rice in east Texas. METHODS Experimental Design and Damage Assessment 1990—We selected study sites based upon willingness of growers to cooperate and their intention to plant about 1 April. Three fields met those criteria, but uncommonly heavy rainfall in March and early April delayed planting two to three weeks. The sites differed in several respects (Table 1), but based on recent history, each was expected to receive heavy bird pressure. At each study site, paired treated and control plots were situated along the field edges where we anticipated high levels of bird activity. The sizes of the treated and control plots were identical at each site but varied among sites (Table 1) due to differences in field configuration. Table 1. Characteristics of study sites used to evaluate Kocide SD as a bird repellent rice seed treatment, east Texas, 1990-1991. In 1990, all sites were seeded by air whereas those in 1991 were drill-seeded.