N.S. Azad Thakur, D.M. Firake, D. Kumar, G.T. Behere and Kanchan Saikia ICAR Research Complex for North Eastern Hill Region, Umiam, Meghalaya
Introduction
Rodents are the most notorious vertebrate pest and frequently cause severe damage to almost all standing agricultural crops, stored food grains, grasses, fodder crops and other useful commodities. Annual losses caused by rodent’s in commonly cultivated agricultural crops are in the range of 2 to 15% and sometimes up to 100% damage during outbreak situations (Islam et al., 1993). In general, bamboo flowering is considered as a harbinger of famine in North-East India. The popular belief is that the gregarious flowering of bamboo produces large quantities of seeds, resulting in a population explosion of rats which feed upon other food commodities, thus damaging stored produce leading to famine (John and Nadgauda, 2002). Lesser Indian mole rat (Bandicota bengalenis), common house rat (Rattus rattus), himalayan rat (Rattus nitidu) and house mouse (Mus musculus) are the predominant rodent species of North-East India (Anonymous, 2008).Tribal communities of the region have been using various methods of rodent management since longer time. Among all, rat traps are the most important tool of rodent management. Trapping rat is an age old method which is ecologically sound and environment friendly. Moreover, different chemical baits are available in the market and are also been provided by the government agencies during outbreak period; where they play additional role in rodent management. However, frequent rainfall situations in the region not only destroy the baits and its effectiveness but also increase the chances of poisoning to the non target organisms. Under such circumstances, locally made bait stations/containers play significant role by protecting the bait from heavy rain as well as weathering, and ultimately improve their efficacy. Additionally, it also reduces the chances of non target poisoning. Thus, attempts were made to collect information on different indigenous traps and bait stations and also to evaluate their effectiveness at different locations in the region.
Methodology
All eight districts of Mizoram state were surveyed during 2004 to 2008 (during recent bamboo flowering). Further, indigenous traps and bait stations were collected from the region and brought to the laboratory. As per farmer’s perception, most popular and effective traps (viz., Vaithang and Chepthang) were selected for their evaluation along with conventional traps (Sherman’s and Snap traps) at different locations in Mizoram. Different bait stations/ bait container were also evaluated for their efficacy. Three most widely used
rodenticides viz., Bromadiolone, Coumatetralyl and Zinc phosphide were selected for the study. Common baits (consisting boiled rice+ jaggery+ mustard oil + rodenticide) were kept inside the indigenous bait containers as well as in bare conditions (on plant leaves) during night time.
Results
Survey on identification of different indigenous rat traps in Mizoram
Indigenous traps, Vaithang and Chepthang or Thangchep were observed to be common and widely used by the farmers in different agro-ecological systems. In addition to that, two more traps, Hnawhtawt and Chehrap or Kharkhip or Kawlper were also used by farmers.
However, later two rat traps were not found popular and efficient during outbreak period.
Therefore, their use was limited and mostly during dearth period of rodents.
Evaluation of indigenous traps at different locations of Mizoram
Among all, the Vaithang trap was found to be highly efficient (70 to 90 %) at different places followed by Chepthang trap (50 to 80%); whereas the Sherman’s traps (10 to 20%) and Snap traps (10 to 30 %) were observed to be far inferior in comparison with indigenous traps (Table 1).
Table 1 Evaluation of conventional and indigenous traps in Mizoram
Name of trap Per cent rat trapping (Mean±SE) in different villages
Tawipui south Theiriat Thualthu Chengoui
Vaithang trap 85±2.89a 70±5.77a 90±2.89a 80±5.77a
Chepthang trap 70±5.77a 50±5.77a 80±2.89a 70±5.77a
Snap Trap 30±5.77b 20±5.77b 20±5.77b 10±0.00b
Shermans Trap 20±5.77b 20±5.77b 10±5.77b 20±5.77b
F Value 35.92 18.00 80.00 49.33
P value <0.001 <0.001 <0.001 <0.001
Note: Figures with different letters are significantly different (Tukey’s HSD test, P=0.05)
Survey on identification of different indigenous rat bait stations /bait containers of Mizoram Local people were found to use indigenously available items like hollow bamboo pieces, broken pitchers and coconut shells etc. for the purpose of bait containers. Normally, the size of different bait stations was about 1 to 1.5 feet long and 6-11 cm in diameter.
Evaluation of different bait stations under field conditions
Consumption of rodenticides using bamboo bait station was significantly higher compared to bait on plant leaves (common method) (Table 2). Consumption of bromadiolone
and coumatetralyl by using bamboo bait station was found to be highest (46.17% and 54.14%, respectively); while it was lowest in case of placement on plant leaves (38.05% and 43.00%, respectively). Similar trend was also observed in zinc phosphide bait.
Table 2 Evaluation of different bait stations under field conditions
Treatment Bait consumption (%)
Bromadiolone bait Coumatetralyl bait Zinc phosphide bait
Bait inside bamboo bait station 46.17 54.14 29.08
Bait on plant leaves 38.05 43.00 17.23
‘T’ value 79.37 9.62 21.64
P value <0.001 <0.001 <0.001
Conclusion
Present study concludes that the tribal communities of North East India have developed most efficient rodent traps and bait stations based on their longstanding experiences.
Therefore, basic idea and design behind these indigenous creations could be utilized in future to formulate new improved traps, which can be further commercialized.
References
Annonymous. 2008. Final Report on ICAR Ad-ho c project on “Survey of rodent species and establishment of relationship between rodent upsurge and bamboo flowering in Meghalaya and Mizoram”. ICAR, New Delhi, 2008, 45p
Islam, Z., Morton R.G. and Jupp, R.P. 1993. The effects of rat damage on deep water rice yield in Bangladesh, Int J Pest Manage, 39: 250-4
John, C.K. and Nadgauda, R.S. 2002. Bamboo flowering and famine, Current Science 82 (3):261-262