As African farmers face increasing pesticide use, effective strategies are needed, writes Nelson Mandela Ogema.
With Africa’s population expected to double by 2050, according to UN estimates, pesticides that can protect crops and boost food production are in growing demand.
Between 2000 and 2019, pesticide use in agriculture in sub-Saharan Africa rose from 64,000 metric tons to 108,000 metric tons, according to market data Statista.
But most farmers in sub-Saharan Africa are unaware of the effects of these chemicals on health and ecosystems, experts say, and pesticides are often misused.
“Agriculture is the main economic activity in sub-Saharan Africa,” Daniel Otaye, a plant pathologist and professor at Egerton University in Kenya, told SciDev.Net.
“Agricultural production in this region faces challenges with pests and diseases that lead to low productivity. In response to pest and disease pressures, there has been a reliance on agricultural pesticides.”
According to Otaye, the most commonly used pesticides in sub-Saharan Africa belong to a group of endocrine disrupting compounds and dichlorodiphenyl trichloroethane, commonly known as DDT.
“Most of these pesticides, while providing obvious benefits when used, present distinct health and environmental challenges in sub-Saharan Africa,” added Otaye.
A study published last year in the International Journal of Environmental Research and Public Health found a link between pesticide use and disorders affecting the brain or reproduction.
“Mistakes and Intoxications”
Otaye tells SciDev.Net that the widespread adoption of pesticides in sub-Saharan Africa suggests that many users are new, inexperienced and usually unaware of the consequences of pesticide use, even when applied correctly.
“The lack of proper regulation and proper training of farmers increases the risk of pesticide misuse and even poisoning,” he says. “Pesticides are toxic to humans and their handling and use requires several precautionary measures.”
Using personal protective equipment and knowing first aid information are some of the precautions to consider when applying pesticides, Otaye recommends.
Nokuthula Hlanga, a postdoctoral researcher in crop sciences at the South Africa-based University of KwaZulu-Natal, tells SciDev.Net that in sub-Saharan Africa, the use of pesticide sprays is expanding among commercial farmers growing conventional crops.
“Conventional crops require intensive pesticide spray schedules to ward off high pest and disease pressures,” he says. “Economic factors are the main drivers of pesticide dependence. The costs of chemical spraying are offset by high yield returns. It makes economic sense to spray rather than suffer large yield losses.”
Hlanga’s increasing reliance on pesticides comes at a cost. Mechanical or manual pest and disease control can be more expensive than chemical control, he explained.
“Chemical application is easily mechanized in commercial agriculture. This reduces the time spent on operations and increases productivity,” he added.
Francis Onyekachi Nwankwo, head of product management at the African Agricultural Technology Foundation in Kenya, says the widespread use of pesticides can lead to their ineffectiveness.
“It’s important to target those organisms that control pesticides
develop resistance over time, which explains enough why [dosage] the recommendations are not followed”, he explained.
“For example, a farmer who applies the required dose to an organism strain that has developed resistance will not get results and this directly informs that increasing the dose can turn the target organism into a super bug, or kill it but harm the environment. The level of these chemicals for human consumption accumulating more than tolerant.”
Safe practice methods
According to Hlanga, applying pesticides through drip irrigation for soil pests is safe and reduces drift to non-target crops.
According to the UN Food and Agriculture Organization, drip irrigation involves the use of small diameter plastic pipes with outlets called emitters or drippers to water the soil at very low rates so that it only affects the part of the soil where the roots grow.
Nwankwo says agriculture in Africa has always been practiced by farmers with few resources, who sometimes misuse pesticides.
“The enormous use of these chemicals, as the saying goes, ‘if a little is good.’
‘More will be better’ has had serious adverse effects on humans and other life forms,” he tells SciDev.Net.
Nwankwo calls on key stakeholders such as governments, private organizations, service providers and farmer associations to collaborate in promoting the proper use of pesticides to control pests and diseases.
He adds: “Increasing dependence on pesticides is simply due to the lack of coordination of various actors to update the scientific aspect of agriculture. What we are experiencing in Africa is that the actors are working in silos without coordination.
Nwankwo says the use of products derived from biotechnology has shown to be a way out, as in the case of a cassava commercialized in Nigeria and Ghana, which is resistant to the crop pest pod borer.
In the meantime, promoting the correct use of pesticides is key, he says, adding: “Strong and conscious efforts should be made to communicate an appropriate message about how these chemicals should be managed.”
He added that one of the safe methods of using pesticides is to follow the recommended dosage.
“Another area that would help encourage safe use and application of pesticides is the expansion and use of the services of a monitoring expert.
regulatory compliance with a view to quality assurance and control of everything related to pesticides,” Nwankwo explained, adding that the expert can provide guidance, training and technical knowledge for anyone involved in the use of pesticides.
Khumbuzile Bophela, a plant pathologist and researcher at the University of Pretoria in South Africa, emphasizes that when choosing to use a pesticide, the specificity of the pest, pathogen or organism that causes a disease must be taken into account.
“Pesticide selection will be determined by knowledge of the pest or pathogen causing the disease in a particular crop,” he tells SciDev.Net.
This piece was produced by SciDev.Net’s Sub-Saharan Africa English Desk.