Protecting Ripening Sorghum with Methiocarb from Bird Damage in Senegal

The simultaneous completion of the rainy season and nesting of granivorous birds between October and November in the Sudano-sahelian region of Senegal often results in very extensive bird damage to cereal crops. This occurs from both increased bird populations, due to the presence of juveniles as well as from their accompanying change in diet from insects to seeds. The damage is caused by several species of birds, most notable the Red-billed Dioch (Quelea quelea) and the Village and Black-headed Weavers (Ploceus cuculiatus and Ploceus capitalis). The Buffalo Weaver (Bubalornis albirostris) and the Glossy Starling Lamprotornis chalybaeus) also are at times serious crop depredators. Traditionally, farmers employ many different frightening techniques to chase or scare birds from their crops. The methods provide at best only temporary relief and require considerable time and energy. A possible solution to the bird problem involves the use of chemical repellents applied directly to the ripening grain. The purpose of the trial reported here was to evaluate methiocarb or Mesurol [4-(methylthio)-3,5 xylyl N-methylcarbamate] as a bird repellent on ripening sorghum. The study was undertaken as a part of the Regional UNDP/FAO Project " Research into the Control of Grain-eating Birds, " aimed at the development and improvement of control techniques to prevent or reduce bird damage to cereal crops. The effectiveness of methiocarb as a nonlethal bird repellent has been demonstrated on several types of crops, among them cherries (Guarino, et al., 1974), blueberries (Bollen-gier, et al., 1973), sorghum (Mott and Lewis, 1975) and rice (DeHaven, et al., 1971). Trials by DeGrazio and DeHaven (1974) on wheat and rice in eastern Africa also have shown promise. Likewise, the Quelea Project has obtained some success with it against Passer Iuteus, Quelea quelea, and ploceus capitalis when applied to both ripening millet and rice (Brug-gers, 1975, 1977). METHODS Test site: The trial was conducted on sorghum variety CE 90 at an Institut Senegal-ais de Recherches Agronomiques (I.S.R.A.) field station at Darou, Senegal. The treated zone comprised four consecutive 550 m 2 bands (2220 m 2 total) adjacent to three other control bands (1650 m 2 total). Treated and control zones were separated by a 0.5 m path and three 15-cm red, plastic ribbons mounted on poles above the sorghum heads. The test parcel was located between fields of millet and sorghum planted by I.S.R.A. personnel for replicate variety trials in a corridor between dense strands of Combretum glutinosum …