October 2008. Rats, probably Rattus exulans, are a problem in the lab at Nu’u Crops Rresearch Station, Samoa. It is a common rat in the coutry, although there are other species, R. rattus and R. norvegicus. Suggestions were requested how the outbreak can be controlled.
There were many replies, most suggesting the use of cats, traps and sanitation. Cats might attack rats, but they wererats, but also instumental in the demise of birds, with very serious effects on biodiversity. It’s a good policy to have domestic cats neutered so they cannot breed if they go feral. In general, domestic cats were not good at reducing rat populations, and sanitation in and around buildings, blocking entry/exit holes, removing breeding sites and the use of baits are proabably better methods.
Snap traps give the best short term solution. First bait unset traps with roasted coconut (tunu popo) and place in runways, and do this for a few nights replacing the bait each day, and as it is taken. Use gloves when handling traps to avoid human odours. Rats can smell humans and cats a mile away. Then set the traps. Trap shyness is reduced and trap success is greatly enhanced. Baits are good, but can also cause problems if the rats decide to die inside the structure.
Herbal repellents were suggested from India, and a range of techniques from Malaysia. Information was given on a Barn owl program in Tamil Nadu, India. The owls were reared and released with good effect. If birds are used, it is necessary to limit bait use as they may be detrimental to birds.
Finally, there was a reminder about Gliricidia leves. Infomration about this can be found on PestNet at: