Field efficacy of anticoagulant rodenticides against rat infestation in oil palm plantation was carried out in a comparative study between five rodenticide baits. They were first-generation anticoagulant rodenticide baits, coumatetralyl, chlorophacinone and warfarin, and second-generation anticoagulant rodenticide baits, flocoumafen and brodifacoum. A control plot was left untreated for comparison purposes. In general, all treatments were effective to reduce the fresh rat damage on oil palm fresh fruit bunch (FFB) below the threshold level (5.0%) except for warfarin bait treatment. In the final round of baiting (5 th round), the flocoumafen bait recorded the lowest fresh rat damage on FFB at 1.54 ± 0.14%. Coumatetralyl, chlorophacinone and brodifacoum recorded 2.95 ± 0.73%, 2.42 ± 0.57% and 4.30 ± 0.53% of fresh rat damage on FFB at the end of the study. The least effective was warfarin treatment which recorded 5.40 ± 0.18% in the final round of baiting. Only flocoumafen, coumatetralyl and chlorophacinone baits recorded more than 70.00% of rat damage reduction throughout the study as compared to pre-treatment. The brodifacoum treatment recorded rat damage reduction up to 58.70% and warfarin treatment was in the range of 13.58%-33.62%. All the rodenticide treatments managed to reduce the relative abundance of the estimated rat population in the field at the end of the study, except in the control plot.

A study was carried out to determine the preferences of rats in damaging pineapple MD2, based on hormonal induced days. Biologische Bundesantalt, Bundessortenamt and Chemische Industrie (BBCH) coding system, a phenology scale for all flowering plants, was used to describe the vegetative growth stage of MD2 pineapple in this study. The evaluation of MD2 phenology was carried out between 60 and 173 days after hormonal flower induction activity. Rat damage was studied at two growth stages, namely fruit development and fruit ripening of MD2 pineapple. The results showed that MD2 pineapple takes around 72 to 95 days to ripen from fruit development. The pineapple is best to be harvested around 140-145 days after hormonal flower induction activity or at BBCH scale 801-805. At this time, the pineapple turns from light green to yellowish green. Two species of rats, namely Rattus tiomanicus and Rattus argentiventer preferred matured fruits in between BBCH scales 800 to 805. Chemical control through rodenticide baiting campaign for rats needs to be done as early as 70-78 days after hormonal flower induction activity or before the BBCH scale 700 as best control measures. Keywords: Biologische Bundesantalt, Bundessortenamt and Chemische Industrie coding system, pineapple, rat damage.