Pakistan J. Zool., vol. 41(3), pp. 203-207, 2009. Control of Rodent Damage to Groundnuts in the Pothwar Plateau Region of Pakistan Abdul Aziz Khan, Iftikhar Hussain* and Shahid Munir Department of Wildlife Management, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Pakistan (AAK, IH) and Vertebrate Pest Management Programme, Institute of Plant and Environmental Protection, National Agricultural Research Centre, Islamabad, Pakistan (SM) Abstract.- Efficacy of 0.005% flocoumafen, 0.0375% coumatetralyl and 2% zinc phosphide was evaluated for small rodents infesting groundnut fields in the Chakwal District of the Pothwar Plateau, Pakistan. The baiting duration was about 10 weeks, starting at the peg formation crop stage until two weeks before harvest. Treatment efficacy was assessed by live burrow counts before and after treatments and by the yield of nuts from treated and untreated reference plots. After three treatments, the reductions in rodent activity were: 70.2% (zinc phosphide), 90.4%, (flocoumafen), and 95.0% (coumatetralyl). The yield of groundnuts, obtained only from the flocoumafen- and coumatetralyl-treated plots, was substantially increased - 61.6% and 59.2%. Partial budget analyses, based on benefit /cost determinations for the rodent control treatments by anticoagulants showed a more than 20-fold economic return for both. Key words: Groundnut crop, rodent damage, control, rodenticides, baits INTRODUCTION Groundnut (Arachis hypogea) is one of the major summer crops grown in the Pothwar Plateau, an uneven, rainfed landscape, in Pakistan. National production of this crop at the country level is 73,900 metric tonnes (GOP, 2007), of which about 70% is contributed by the three districts (Chakwal, Attock and Rawalpindi) of the Pothwar region (Ahmad, 1990). Average per hectare yield is about 1194 kg. This relatively low yield is usually attributed to many biological and environmental factors such as losses caused by diseases, insects, and rodent pests, low yielding varieties, and rainfall uncertainties. Five species of field rodents; Bandicota bengalensis, Nesokia indica, Tatera indica, Golunda ellioti and Mus spp. have been recorded from the crop fields of this area and except for G. ellioti the other species are considered to have pest status (Brooks et al., 1988; Hussain et al., 2003). On-farm constraints studies revealed that rodents severely damaged groundnuts in Pothwar and were perceived to be a limiting factor in achieving optimum production (Ali and Iqbal, 1984; Ali et al., 1984). These researchers also indicated that the * Corresponding author: E-mail: ifthussain@uaar.edu.pk 0030-9923/2009/0003-0203 $ 8.00/0 Copyright 2009 Zoological Society of Pakistan. spreading groundnut varieties were more susceptible to rodent damage than the erect ones. Ahmad (1991) reported that the majority of farmers (77%) in groundnut growing districts realized that vertebrate pests (principally rodents) were a problem, while 44% considered them a factor for limiting production. Islam (1987) estimated that vertebrate pests caused 17% yield reduction. Brooks et al. (1988) estimated 3.4% loss of the groundnut crop in Pothwar area due to rodents, with a resultant mean yield loss of 43 kg/ha. Groundnuts are one of the most important subsistence crops in some arid and semi-arid countries but little information is available on the losses caused by rodents which can reach 100% locally (Meehan, 1984). Bindra and Sagar (1971) assessed loss in yield of groundnuts that ranged from 12-31 Kg/acre with an average of 20 Kg/acre. Prakash and Mathur (1988) reported rodent losses to the groundnut crop in India from 4 to 26%, while, according to Parshad et al. (1987), the yield loss of groundnuts to these pests was 3.86%. Low yields of groundnuts, because of rat damage, have also been reported from Philippines and Sudan (Baltonado and Bongolan, 1985; Ishaq et al., 1980). In China, an enclosure study of groundnut damage by the rat-like hamster, Cricetulus triton, has revealed 14.8-19.6% damage (Zhang et al., 1998). Survey of literature offers scanty information