Brodifacoum was evaluated in the laboratory against the two gerbils, Tatera indica and Meriones hurrianae and the house rat, Rattus rattus. The acute oral LD50 for these rodents was found to be 0.10 mg/kg, 0.083 mg/kg and 0.77 mg/kg respectively. Feeding tests with 0.002% and 0.005% brodifacoum produced a 100% mortality after a 3-day feeding period in the gerbils and after a 4-day period in R. rattus. The anticoagulant is toxic at both the concentrations to all three species but is less palatable in comparison to plain baits. Results of this laboratory evaluation indicates that 0.002% brodifacoum-treated bait can be effectively used against T. indica, M. hurrianae and R. rattus.

SUMMARYIndividually caged northern palm squirrels, Funambulus pennanti, were fed with bait containing 0-025 00 warfarin or fumarin, 0'0075 % chlorophacinone or 0-005 %o brodifacoum for a fixed number of days varying from 1 to 14. Brodifacoum (WBA 8119) was found most toxic since 66 % and 70 % of the animals died after one and two days' feeding respectively. Chlorophacinone killed 70 % of the squirrels after three days' feeding. Squirrels were relatively tolerant to warfarin and fumarin since the mortality after a period of 14 days' feeding was only 58 % and 75 % respectively.

Brodifacoum, chlorophacinone and coumatetralyl treated pearl millet (Pennisetwn typhoides) grains were tested in a desert scrub grassland to evaluate the comparative field efficacy of these three anticoagulant rodenticides. Baits were placed for 10 consecutive days in bait stations in 18 plots of one hectare each in a randomized block design. Per cent reduction in rodent population was caIcu1ated by pre arid post-treatment active burrow counts, census baiting and live trapping. Results revealed that brodifacoum is significantly more effective than other two anticoagulants. However, analysis of variance revealed significant difference in the estimation of per cent reduction in the rodent population caJculated by three methods, the possible reasons for which are also discussed.

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Held trials were conducted in 18 1-ha plots arranged as a 6×3 randomised block to evaluate brodifacoum (0.002%), chlorophacinone (0.0075%) and coumatetralyl (0.0375%) for the control of desert rodents, predominantly Meriones hurrianae Jerdon. Success was measured by counts of inhabited burrows before and four days after the treatment period of ten days. Average kills were 90.5, 83.2 and 81.1 % respectively. It is concluded that all three poisons are effective, but brodifacoum performed significantly better than either chlorophacinone or coumatetralyl.