General Information

Rat field rat
Scientific name: Rattus argentiventer, R. exulans, R. rattus spp., R. tanezumi
Rodentia : Muridae
Common name: Riceland rat, Rice rat, Rat

Hosts

Rice, corn, peanut, bell pepper, sweet potato, cacao, coconut, African oil palm

Distribution

Southeast Asia

Damage

Newly sown seeds at the seedbed are eaten by rats as well as the endosperm on the pre-germinated ones. Re-sowing is needed once the damage is so high.

On the transplanted seedlings, they cut and chewed the tillers.

During the booting stage, they chew the tillers near the base and feed on the developing buds and heads.

During the grain-filling stage, they make an oblique cut on the rice stalk bearing the inflorescence and feed on them.

During a severe rat infestation, all the rice plants are attacked and left totally void of grains.

Description

Rice field rats are brown to black in color. They have scaly, thinly furred tails, and distinctive chisel-like incisors. A commonly found rat species has a tuft of red hair at the base of its ears, orange-brown fur that is streaked with black on its back, and has a silvery white belly. They can live for one year or longer.

The female rat can reproduce up to four times a year for she easily gets pregnant again after a few days of giving birth. She can produce an average of 6 pups per litter and 24 weaned offspring in a year. Pregnancy lasts for 3 weeks.

The pups are ready to mate after 6 weeks.

Their population build-up and the amount of damage they cause are closely related to the crop's growth and development. If there is one crop planted in a year, there is only one breeding season. If there are two rice crops in a year then there are two breeding seasons. If the harvesting is staggered by more than one or two weeks within a single cropping area, the rat colony will move from one field to another causing severe damage to the remaining crops.