WARFARIN RESISTANCE OF Rattus tiomanicus IN OIL PALMS IN MALAYSIA AND THE ASSOCIATED INCREASE OF Rattus diardii

摘要: Author(s): Wood, B. J.; Chung, G. F. | Abstract: Rattus tiomanicus is a serious pest of oil palm plantations in Peninsular Malaysia, feeding on the ripening fruit. R. diardii rat human habitations and has been only an occasional field species, presumably because it cannot compete with better adapted species. A widely used control for proven effectiveness uses maize-based baits containing warfarin at 0.05% 2 cm3 (14.5 g) wax-bound cubes. These are applied campaigns one per palm, replaced 4 daily rounds, until acceptance declined to 20%. This "standard method" about 6-month intervals, populations remain low. In early 1980s resistance began tiomanicus, from same time was found more often palms, apparently localities. review studies these phenomena. Rat population by mark, release, recapture (MRR) confirmed that baiting failing against or required prolonged application, whereas second-generation anticoagulants (brodifacoum, bromadiolone, flocoumafen) were effective. Physiological laboratory. Direct substitution compounds increased cost considerably, ways reduce costs investigated. Smaller bait size presented problems monitoring acceptance, longer intervals between replacements did not consumption. Half active ingredient concentration had some promise, but first-round application two palms most practicable. Bromadiolone 0.005% now half density first areas resistance. Where problem noted, compared without continued baiting. 81-ha plot left unbaited, gradually during 1982-84. then remained predominant 1989. baited plot, once bromadiolone (from 1984) both species controlled. It postulated became able out-compete genotype latter somehow weakened rapid selection