Three types. Pacific rat (Asia and Pacific islands, small, nests on the ground); black rat (worldwide, often nests in trees) and brown rat (worldwide, mostly in human settlements; nests underground). Important pests.
Attack cassava, cocoa, coconut, oil palm, peanut, maize, rice, sweetpotato, and others in storage; also, carry fleas with bacteria causing scrub typhus.
Cultural control: do not leave food for rats to eat; aluminium bands around coconuts; snap-traps; cats.
Chemical control: Gliricidia leaves (or Barringonia, flesh of fish poison tree) mixed daily with e.g., cooked rice or root crops; alternatively, warfarin or brodifacoum in baits with coconut, wheat or maize (place in e.g., bamboo sections. Put out in evening and collected in mornings.