- Each year, 385 million cases of pesticide poisoning are reported worldwide, according to the Pesticide Action Network.
- As researchers develop alternatives, farmworkers and environmentalists are raising questions about what should replace hazardous agricultural chemicals.
- One leading alternative is genetically-engineered pesticides, such as RNAi sprays — but there are still important gaps in assessing the safety and effectiveness of these new technologies.
- As further research and studies gather evidence of how GE pesticides might affect farmers and the landscapes they work in, campaigners are making the case for biopesticides.
Insects like fall armyworm or mealybugs can decimate food and commercial crops; like their counterparts elsewhere in the world, South Africa’s small and large farmers alike use synthetic chemical pesticides to control these and other pests.
But about 385 million cases of unintentional acute pesticide poisoning are reported worldwide each year, according to the Pesticide Action Network, an umbrella group of more than 600 NGOs in 90 countries campaigning to reduce the use of chemical pesticides. As researchers look for alternatives, new pesticides that use genetic technologies are raising questions about what should replace hazardous agricultural chemicals.
Colette Solomon, co-director of Women on Farms Project, an organization that advocates for farm workers and farm dwellers in South Africa, says pesticides are often sprayed while female farm workers are harvesting crops. In many cases, these workers, mostly women, are not provided with gloves or other protective equipment, she told Mongabay, as hand protection is seen as impractical for the handling of delicate fruit such as grapes.
“[The workers] are not provided with PPE, such as hand protection, or they’re not practical for the delicate types of work they do, leaving them to handle contaminated vines barehanded, as well as breathing in these chemicals” Solomon said.
Even when agrochemicals aren’t sprayed while women are working, they must often re-enter vineyards soon after they have been sprayed, she added in an email interview, and because farm workers’ homes are often located next to vineyards, pesticides can also drift into their houses.
Led by environmental epidemiologist Regina Molomo, a team of researchers collected urine samples from 9-15-year-olds in one fruit-growing area in South Africa between 2017 and 2019 and analyzed them for biomarkers of pesticide exposure. They found that 60% of those tested showed signs of recent exposure to various pesticides.
Forty percent of the surveyed children lived on farms; 80% had at least one family member working on a farm.
Molomo and her colleagues also interviewed the children and found many of them reported seeing pesticide spray drift from farms onto their homes in Grabouw, Piketberg and the Hex River Valley, as well as regular use of household pesticides by their families. The researchers also found children from households that used open water sources had higher levels of pesticide biomarkers than those relying on taps, boreholes or other closed sources of water.
Phasing out harmful agrochemicals
A recent seminar organized by the African Centre for Biodiversity (ACB), which has campaigned against genetically-engineered organisms in Africa since 2003, put a spotlight on two potential alternatives to hazardous agrochemicals: Biopesticides and genetically-engineered pesticides.
Biopesticides use plant extracts or organisms such as bacteria and fungi to kill pests. Mariam Mayet, executive director of the ACB, told Mongabay that farmers around the world have long used biopesticides including extracts from the neem tree (Azadirachta indica) and pyrethrum, made from chrysanthemum flowers, to control pests.
“They’re quite distinct from genetically-engineered or gene-silencing pesticides,” Mayet said.
Genetically-engineered pesticides use technologies that their proponents say allow them to precisely target only specific pests. They include RNAi (ribonucleic interference) sprays disrupt their target species’ cellular functions — the sprays contains modified RNA molecules that interfere with how a pest’s cells carry out instructions stored in their DNA.
Other GE pest-control methods use CRISPR technology to change or disable a specific gene or trait; researchers can then, for instance, breed and introduce insects that have been genetically-edited to be sterile into a population to hinder that species’ reproduction.
These approaches, which would release living, genetically-modified organisms into farm landscapes, are still in development and testing, while some RNAi pesticides have already been deployed.
Assessing safety
Sarah Zanon Agapito-Tenfen is a plant geneticist and biosafety researcher at the Norwegian Research Centre (NORCE), who was part of a recent international task force of about 20 scientists that reviewed more than 40 years’ worth of studies on genetically-engineered pesticides.
Speaking at the ACB’s webinar, she said that out of 700 research papers the task force examined, just 23 looked into the GE pesticides’ effects beyond their target species — and half of these lacked controls to make them valid studies.
Of the dozen studies the task force deemed sound — all looking at the impacts of RNAi sprays — 11 detected effects on non-target organisms.
Agapito-Tenfen said this means there is still a lot of missing information about how RNAi pesticides might affect, for instance, fungi that help plant roots absorb water and nutrients from the soil, or pollinators like bees.
“This is not a large literature with gaps. This is a very small literature. Whole parts of the picture are missing,” Agapito-Tenfen said.
Gudrun Dittrich-Schröder, who researches genetic methods of pest control at the Forestry and Agricultural Biotechnology Institute at South Africa’s University of Pretoria, takes a different view, though she acknowledges more research is needed.
RNAi sprays, she told Mongabay via email, could provide an additional tool to reinforce a broader, integrated pets management strategy, offering farmers a way to control pests that have developed resistance to conventional techniques.
The sprays will need to be assessed for their toxicity and how they affect their environment, she said. (She was aware of only one RNAi study in Southern Africa, a lab test of genetically-altered RNA on mealybugs, that was published earlier this year.)
Genetically-engineered organisms intended for release, on the other hand, need additional levels of ecological and genetic assessment, especially when the genetic modifications are designed to spread.
“Releasing a living, reproducing organism raises different questions from spraying a product,” she said. For instance, an insect may be genetically-modified to pass on a changed trait like any natural mutation, or scientists can modify it so it produces both the changed trait AND the CRISPR proteins that cause the genetic changes — this is known as a “gene drive” and causes the changed trait to spread through a population more often than normal.
The safe development and deployment of such pesticides, Dittrich-Schröder concluded, calls for proportional, evidence-based assessment of the new technologies, identifying the specific hazards each product may present, testing for them, and then creating regulations appropriate to the level of risk associated with each.
“Important research gaps remain,” she told Mongabay. “Research gaps show that data are lacking; they do not by themselves demonstrate harm.”
Biopesticides may be a better alternative, some say
Anna Shevel, network coordinator of UnPoison, a South African nonprofit organization campaigning to end the use of highly hazardous pesticides, said biopesticides offer South Africa’s farmers a faster, safer alternative to agrochemicals than genetically-engineered pesticides.
She said this is because South Africa already has “great” guidelines which require biopesticide manufacturers to identify all the ingredients in their product, and set out potential risks to crops and the environment — including to wild plants and pollinators. They also have to provide instructions for safe use and storage.
In South Africa, both chemical and biopesticides are reviewed by the same registration authority, but while a chemical pesticide can get registered within six to 12 months, biopesticides have their own testing and documentation requirements.
However, Shevel said, approval for biopesticides sometimes stalls in the registrar’s office of South Africa’s Department of Agriculture. “South Africa introduced a biopesticide and biological control guideline in 2015, which is really great. But the problem is that it hasn’t been capacitated in the registrar’s office,” she said.
So these products are still passing through the same registration pathway as synthetic agrochemicals, causing many of them to be blocked by assessors who lack the technical capacity to adequately evaluate them. “It’s like trying to put a dugout canoe through a bullet train [of] health and safety trials and testing,” she said.
Some biopesticides are already in use in South Africa. One example is already being used successfully on commercial farms, Dittrich-Schröder told Mongabay, is a naturally occurring insect virus, Cryptophlebia leucotreta granulovirus, which has been used for years to control false codling moth (Thaumatotibia leucotreta), a pest whose larvae feed on citrus fruit.
“It was at least as effective as the chemical alternatives tested,” she said. It was also rated harmless to key insects that help control citrus pests by eating them or laying eggs in or on them.
Protecting health and the environment
The health and ecological effects of agrochemicals make the question of how to reduce their use an urgent one — and one that extends beyond farmworkers health. Mayet says that testing commissioned by ACB found pesticide residue in 86% of common South African food items, including bread, maize meal, fruit and vegetables, and infant foods. In 2024, a tragic case of six children who died after eating snacks that had accidentally been contaminated with the highly-toxic pesticide Terbufos, dominated the headlines for weeks.
Africa presently accounts for a small share of global pesticide use, says Mayet, but as use of pesticides has worldwide has rapidly increased over the past 30 years, she is pesticide producers see African markets as offering new, untapped possibilities for expansion.
This makes sound research, strong policy, and effective regulation and enforcement even more important, she said. New regulatory and commercial precedents are being established. “They help normalise RNA sprays, engineered biological products and synthetic biology-derived pest-control tools as ‘sustainable’ alternatives to chemical pesticides, even though many unresolved questions remain about ecological effects, off-target impacts, resistance, monitoring, liability and corporate control.”
The ACB’s Mayet said the most effective alternatives are not simply “safer pesticides,” but farming systems that rely on techniques like intercropping, agroforestry and attracting natural pest predators to reduce the need for pesticides in the first place.
“The safest pesticide is the one farmers do not need to use because the farming system itself is healthy, diverse and resilient,” she said.
The women farm workers who pick fruit and vegetables by hand for minimum wage, in South Africa the equivalent of less than $2 an hour, for the country’s commercial fruit and vegetable sector, want to see an end to chemical-dependent, commercial, capital and water intensive monocultural agriculture, Solomon says.
“Driven by profit maximization rather than workers’ rights, working conditions and health, we don’t imagine that these ‘alternatives’ [genetically-engineered pesticides] can be the solution,” Solomon said.
“Pesticides treat symptoms. Agroecology addresses the conditions that make crops vulnerable to pests in the first place,” said Mayet.
Banner image: A worker pruning fruit trees in South Africa in 2007. Image by Trevor Samson/World Bank via Flickr (CC BY-NC-ND 2.0).
Citations:
Boedeker, W., Watts, M., Clausing, P., & Marquez, E. (2026). Worldwide unintentional acute pesticide poisonings: Reassessing the occupational and non-occupational burden. Frontiers in Public Health, 14. doi:10.3389/fpubh.2026.1825899
Molomo, R. N., Veludo, A. F., Grünig, M., Lindh, C., Röösli, M., Dalvie, M. A., … Fuhrimann, S. (2026). Recent and ever exposure predictors of urinary pesticide biomarkers among children in South Africa: A two-year longitudinal study. Environmental Pollution, 129057. doi:10.1016/j.envpol.2026.129057
Gallego‐Giraldo, C., Urbaneja, A., Ruíz‐Rivero, O., Aragonés, V., Guijarro‐Guijarro, M., Daròs, J., … Perez‐Hedo, M. (2026). Gene‐specific double‐stranded RNAs induce mortality in the South African mealybug Delottococcus aberiae. Pest Management Science, 82(6), 5184-5194. doi:10.1002/ps.70626
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