Since Farmer’s Weekly published a previous article on rat infestation in South Africa in 2016, the problem has escalated markedly, leaving many areas overrun by the rodents. This is according to Dr Gerhard Verdoorn, operations and stewardship manager at CropLife South Africa.
The brown rat (Rattus norvegicus) is the most plentiful in the country. Verdoorn ascribed the current rat population explosion to poor waste, hygiene and rodent management in urban areas, including townships and informal settlements.
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“In some of the areas I visited to ascertain the severity of the infestation I saw rats crawling around in their hundreds. This situation is extremely dangerous since the rodents can cause diseases such as rat-bite fever, bubonic fever and salmonella. Bubonic fever antigens were found in some rats in Johannesburg a few years ago.”
According to Verdoorn, it seems as if the authorities are not aware of the true extent of the problem. He said the infestation was caused by waste, especially food waste, left on the streets and in backyards. This forms the ideal habitat for rats, which enjoy sufficient cover, food and water.
“The situation calls for intensive and well-coordinated rodent management on a national level. The country’s decision-makers must, as a matter of urgency, implement measures to take control of the rodent problem. The situation is dire,” he said.
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Brown rat outbreaks on farms are not uncommon, where the rats invade storerooms and packhouses. The rats could potentially cause serious problems for farmers. For instance, rat urine and droppings on animal feed could result in salmonella infections in livestock.
Verdoorn emphasised that only rodenticides registered to control rodents must be used, with strict adherence to the instructions on the packaging.
He said the utmost care was called for in the application of rodenticides to prevent the poisoning of domestic animals, birds and humans. A rodenticide registration code starts with ‘L’, followed by four digits and Act No. 36 of 1947 printed on the label.
Verdoorn added that Jack Russell dogs were excellent rat catchers and were very effective in reducing population numbers.