How pest control affects climate change
by Arnold Letsholo
It sounded like an informative joke. During a SADC Council of NGOs policy dialogue on climate change, a participant from Lesotho told fellow delegates how traditional practice can help curb the contamination of soil by chemical insecticides and fertilizers.
“Maybe the whites here among us may not know it,” he said amid bemusement and murmuring from the Caucasian participants present. “But in Lesotho one just goes to consult a traditional woman. After consultation she instructs one to collect soil samples from various points of one’s ploughing field. She mixes the samples with her ‘things’ and one goes back and places the mixture where she instructed... One’s field is therefore pest free and more fertile for months.”
As laughter the Gaborone Sun, the venue for the meeting, the participant from Lesotho sounded a tad misplaced in such a forum of experts, journalists, religious representatives, even ambassadors.
Yet his hapless comments may have value. According to research on climate change, some 20 percent of the global anthropogenic green house gas emissions are from the agricultural sector, 50 percent from the enteric fermentation and rice paddies, 70 percent from artificial fertilizers, while 5 percent of global carbon dioxide emissions are from fossil fuel consumption and biomass burning.
Indeed, does Botswana have the type of ‘specialists’ the participant from Lesotho talked about? A visit to a Motswana woman who sells traditional herbs near Borakanelo Police raised hope only to immediately shatter it. Her welcoming demeanour quickly vanished.
“I do not have anything that can keep pests away, but I do have muti that keeps the soil fertile and protects plants from excessive heat,” she said. “We do not train people but sell these herbs...If you are not buying then pass on, do not waste your time talking.” She did not want to even divulge how much her stuff costs or what her name is.
In Setswana, the kind of process where one – either a farmer or an ordinary individual – seeks assistance from an expert who mixes powdered roots to solve problems like the one discussed above is called ‘go upa’. These experts might use the plants you know but do not know how they are used. They are unlike modern scientists who disseminate information on their findings to the world.
Plants researchers the world over have discovered some plant species that sustainably control pests. Unlike chemical insecticides or pesticides, the plant compounds work on the insect’s hormonal system and not on the digestive or nervous system and therefore do not lead to development of resistance in future generations.
Researches show that more than 500 arthropod pest species have become resistant to one or more chemical insecticides. With the plant compounds method, insects and pests are not killed immediately, but are both repelled and have their growth and reproduction disrupted.
An Indian tree called Neem has such compounds, also known as ‘limonoids’, according to a report published by the Neem foundation. The report further shows that the most significant of limonoids found in the Neem plant with the ability to block insect growth is Azadirachtin. It appears to cause 90 percent of the effect on most pests.
“Research over the past years has shown that it is the most potent growth regulator and feeding deterrent ever assayed. It will repel or reduce the feeding of many species of pest insects as well as some nematodes. In fact it is so potent that a mere trace of its presence prevents some insects from even touching plants,” says the report.
A visit to a local scientist at the Botswana College of Agriculture (BCA) unveiled some of the shortfalls Batswana have fallen into because of the country’s economic status. This has left them opting for expensive chemical pesticides instead of the organic practice used in the past or in some rural areas.
“Batswana know the plants they used to burn and then use their ashes during grain storage. Animal dung was also burnt and used during grain storage,” explained Dr Kebadire Mogotsi, the BCA Agriculture –Coordinator: Useful Plants Project. “And this (dung) was also originally plants. But they prefer buying imported expensive preservatives. Sometimes it is because those who know the preservatives keep their knowledge to themselves.”
She said among known pesticides are tobacco, onion, garlic which everybody knows about. Asked how sustainable plant pest management can be over the chemical one, Mogotsi thoughtfully said, “I do not know what you mean. As a conservationist I would rather have a harmless and effective method of pest control that may take a while to show results than a fast method that will bring profits while negatively impacting the environment in which it is being operated. That cannot be the approach of someone who is in need of quick cash.”
Mogotsi went on to say in other African nations where the economy is lower than Botswana’s, people are still using plants pest control methods, even for the control of mosquitoes.
She showed this writer a report indicating how some plants, well-known in Botswana by Batswana, are merely under experiment as recorded by correspondents in Botswana, Zimbabwe, Mozambique, Zambia, Tanzania, Kenya, Uganda, Ethiopia and Ghana. In most of the countries, such plants are traditionally used for pest control. Monepenepe, commonly used as medicinal herb, and Mosalaosi, are but some of such common trees.
Instead of using plants Batswana prefer chemicals. During the wet season characterised by mosquitoes breeding, supermarkets are going to make a killing through mosquito coils and other chemical repellents.
Given the revelation by Botswana’s own scientist, it is worth concluding with a caution that with climate change hovering over the world, life is no longer as rosy as it used to be. Not even to a wide country with a small population. Not even to a country that rose from being one of the world’s poorest to a middle class economy.
Sustainability should be everyone’s top priority. There is no second planet. The soils, plants and the whole ecosystem should be kept intact. This calls for collective responsibility by all. As entrepreneurship, including the agricultural type, continues to dominate various forums, will the crucial protection of the farming land gain priority? Batswana should share information for the benefit of the present and future generations. The government should lead in mobilization for sustainable development.