Pacific Pests, Pathogens and Weeds - Online edition

Pacific Pests, Pathogens, Weeds & Pesticides

Rats (035)

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  • 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.
Common Name

Polynesian rot, black rat (also called ship rat), brown rat

Scientific Name

Rattus exulans (Pacific rat); Rattus rattus (black rat); Rattus norvegicus (brown rat).

AUTHORS Helen Tsatsia & Grahame Jackson
Information from CABI (2019) Rattus (rats) Invasive Species Compendium. (; and Rat - Wikipedia. (; and Rattus exulans (Pacific rat) (2019) Invasive Species Compendium. (; and Rattus rattus (black rat) (2019) Invasive Species Compendium. (; and from Rattus norvegicus (brown rat) (2019) Invasive Species Compendium. ( Photos 2&4 Gerald McCormack, Cook Islands Biodiversity & Natural Heritage ( Photo 3 Black rat. Wikipedia. ( Diagram Vergleich_Hausratte_Wanderratte_DE.svg, based on the work by Karim-Pierre Maale. ( Photo 5 Snap trap. (

Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat of the Pacific Community.

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