Often, we believe that washing fruits and vegetables removes all pesticides, making them safe to eat. However, this is not the case as these chemicals are absorbed into the food, and we end up consuming them unknowingly. In Rwanda, chemical pesticides are widely used in agriculture, but their effects on health and the environment is to an extent, underestimated.

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According to the National Institute of Statistics of Rwanda (NISR), approximately 41.9% of farmers applied chemical pesticides in Season A of 2025. Among these, 40.6% were small-scale farmers, and 86.9% were large-scale farmers. The most commonly used pesticides were Rocket (41.7%), Dithane (18.6%), and Cypermethrin (16.3%).

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In an interview with The New Times, Adrien Ishimwe, a crop scientist and managing director of Agro-excellent Company Ltd in Musanze, a company that promotes organic farming, explained how pesticide residues contribute to chronic illnesses and harm essential ecosystems. He discussed safer practices, and called for stronger institutional support to grow organic agriculture across the country.

The excerpts;

What are the health risks associated with consuming food grown using chemical pesticides and synthetic fertilizers?

People who consume food produced with chemical substances like pesticides and synthetic fertilizers are at risk of many health issues. These include chronic illnesses such as cancer and diabetes, as well as problems like diarrhea and irritation in the body. Some even report issues related to hearing and smell, which might result from exposure to chemical residues.

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The danger is that once these pesticides are sprayed on crops, they penetrate into the tissues of the plant. Even after washing fruits or vegetables, these chemicals do not go away. They remain in the produce and eventually get into the body when consumed.

Is washing fruits and vegetables enough to reduce the health risks from chemical pesticides?

Washing helps with dirt, but not with chemicals that have already been absorbed into the tissues of the plant or crop. These residues remain inside and continue to affect the body after consumption. Some people think washing the product solves the problem. But that’s not true.

When someone eats food that contains high levels of chemical pesticides, these substances start to accumulate in the body. For example, the food may contain around 50 grams of pesticide residue over time. This buildup leads to complications. The more contaminated the food, the greater the risk of harm. Depending on the type and quantity of chemicals used, these residues can disrupt body systems, damage internal organs, and, over time, increase the risk of diseases such as cancer.

We know pesticides kill pests. But how do they affect helpful insects like bees and the overall health of the soil?

The use of chemical pesticides affects not just people, but also the entire ecological system. When sprayed on crops, they don’t just target the harmful pests, they also destroy beneficial organisms in the soil and surrounding environment like bees, which are important for pollination, and termites, which help in decomposing organic matter to enrich the soil.

When bees die, you lose honey, and natural pollination, which is essential for crop development. Similarly, when soil organisms die, the balance of nutrients and the soil structure is compromised. This leads to poor soil fertility in the long term. Some of these chemicals also release toxic gases into the environment, which can contribute to climate change.

Over time, such emissions can disrupt the weather patterns and increase greenhouse gases. So, the impact is not just on health and crops, but also on the climate and overall environment.

You have mentioned climate change, biodiversity loss, and ecosystem destruction. Could you give a specific example of how this plays out on the ground?

Let me give a simple example. Animals that feed on plants also contribute to the fertility of land, either through their manure or other natural processes. If those animals are poisoned by eating crops treated with chemicals, they die, and we lose organic fertilizer sources.

Without bees, we cannot get honey, and many crops will not be pollinated. That breaks down the reproductive cycle of plants and threatens the survival of many species. These are the longer-term consequences that many people don’t consider when using chemical pesticides.

What safer alternatives can farmers adopt to reduce pesticide use while maintaining crop yields?

The first step is to move toward organic farming. This means using organic biopesticides instead of chemical ones, and using organic fertilizers to improve soil fertility. In Rwanda and across Africa, we need to produce organic pesticides that are effective at controlling pests and diseases.

High humidity often leads to crop diseases such as late blight and anthracnose. However, organic pesticides can be made from locally available materials, including minerals like titanium and magnesium, or naturally insect-repelling compounds. One example is wood ash, which has been used in traditional farming to control certain insects. It works by creating a hostile environment for pests.

Another example is push-pull technology. Here, a farmer plants maize and then grows a plant like desmodium around the edges. Desmodium produces a smell that repels harmful pests. These are part of cultural methods that help manage pests naturally. We also have formulations in powder form, not liquid, that can be stored safely and used when needed. These organic products help conserve biodiversity, reduce greenhouse gas emissions, and improve human health. They are environmentally friendly and sustainable.

Are these options used in Rwanda?

Not yet widely. Our company, Agro-excellent Company Ltd, is in the process of developing and testing organic pesticides for local use. They are not yet on the market, but we are using them on our own farm as part of the trial phase. The goal is to expand their use across the country once they are fully tested and approved. But we need more support to make that happen.

How aware are farmers of the dangers posed by chemical pesticides?

Unfortunately, many farmers are not fully aware. Most do not understand the risks to their health or to consumers. They also do not always use the right equipment. For example, they might spray chemicals without wearing masks or protective clothing. Some use high quantities of pesticides, thinking that more is better but this only increases the danger to themselves and others.

What kind of training or support is your company providing to farmers?

We are already training farmers in organic practices. For example, we have trained 20 farmers in Kayonza District and 20 in Musanze District. These trainings are done on the field, where our technicians go directly to the farms and show the farmers how to produce and apply organic fertilizers, mix organic materials, manage pest and disease pressure using integrated pest management, and space their crops properly. We show them how to use ash, make compost, and apply natural repellents. This is ongoing, and we hope to reach more farmers over time. The trainings started this year, and are done gradually, district by district, depending on available resources and interest from the farmers.

What kind of support is needed to scale this work nationally?

We need institutional support from different levels. First, the ministry of agriculture can help in supporting the development of organic fertilizers and biopesticides.

Second, Rwanda Agriculture and Animal Resources Development Board (RAB) can assist by facilitating access to local and international markets for organic products.

We also need support from the Ministry of Local Government to set up policies that promote organic farming. That includes providing subsidies, funding community-based projects, and encouraging grassroots innovation. Lastly, the Ministry of Health has a role to play by showing the public how consuming food contaminated with chemical substances affects their health. This could help increase demand for organic products.