Response of rice plants to rat damage at the reproductive phase

Abstract

Rats are the most important among the vertebrate pests of rice. They attack stored grain and rice plants growing in the field. More than 20 species of rats attack rice. The most important rodent pest species belong to the genera Rattus, Mus, and Bandicota. Their distribution depends on geographic location and agroecological situation. Rats can attack rice plants throughout their growth period. However, the attack intensifies during maximum tillering, when the rice canopy becomes dense. The rats cut the rice tillers and panicles, store the panicles inside their burrows, and eat the grains. Damage at the reproductive phase is generally considered to result in a total loss of yield because there is insufficient time for compensation to occur. A few stem-cutting experiments in deepwater rice (Poche et al 1980, Haque et al 1986) failed to provide evidence to support this hypothesis. Recent studies have also indicated that plants probably respond more strongly to artificial than to actual pest damage (Islam and Karim 1999).