Repellency and choice: feeding responses of wild rats ( Rattus norvegicus) to cinnamic acid derivatives

Plant secondary compounds and other chemical compounds known to deter feeding in birds were tested for their repellency against wild rats under two-choice and no-choice conditions. In two-choice tests, where treated food was presented with a control diet, rats avoided eating cinnamamide, ferulic acid and dimethyl anthranilate (DMA), but did not significantly reduce consumption of cinnamic acid. In no-choice tests, where rats were offered only the treated diet, cinnamamide (at 0.5% weight/weight) reduced consumption by 62%, while DMA had little effect. Cinnamamide has low toxicity and could be useful in protecting crops, stored products and farm structures where pesticides would be hazardous.