The impact of Furadan 3G (carbofuran) applications on aquatic macroinvertebrates in irrigated rice in Senegal

The impact of Furadan 3G applications (carbofuran, granular formulation; dose rate 1 kg a.i./ha) on aquatic macroinvertebrates was studied in irrigated test plots with rice in northern Senegal. Total biomass of macroinvertebrates and numbers of Odonata, Ephemeroptera, Mematocera (Diptera), and Hydrocorisae (Hemiptera) were severely and significantly reduced after treatment, and remained significantly lower than those in control plots until at least 24 days after treatment. No effects could be demonstrated on Veliidae (Hemiptera), Coleoptera, and Arachnida. In an in situ bioassay, Ephemeroptera was the most sensitive taxon, showing 50% mortality at 18-19 days after treatment. Side-effects of carbofuran applications were also observed in frogs and birds; some birds that consumed spilled granules died immediately. Furadan 3G applications, as practiced in the region, causes dramatic effects on many nontarget organisms. Its use is hazardous to wildlife, and it severely reduces the significance of irrigated rice fields as a feeding habitat for birds, including waders, and other insectivorous organisms. © 1991 Springer-Verlag New York Inc.