By Kilimokwanza
There is a convenient assumption buried in conversations about vegetable production and nutrition in Africa: that more vegetables, grown by more farmers, is unambiguously good for dietary health. The July 2025 research brief titled Vegetable, Fruit, and Staple Crop Production and Input Use: Baseline Findings from the FRESH End-to-End Evaluation (Tanzania Evaluation, Research Brief 3, July 2025), and its companion food safety research from the same CGIAR programme, together complicate this assumption in ways that deserve serious policy attention.
The baseline brief, which assessed agricultural production and input use across 815 vegetable-farming households in Arusha and Kilimanjaro between October 2023 and January 2024, found that tomato farming stands apart from every other vegetable in the study in both its commercial orientation and its chemical input intensity. The question the data raises is whether the tomatoes that dominate the fresh produce market in northern Tanzania are reaching consumers safely.
The Input Profile of Tomato Farming
The numbers are unambiguous. Among the 91 households farming tomatoes in the sample, fertiliser use reached 95%, the highest of any vegetable in the study. Inorganic fertiliser use specifically was 82%. Pesticide use was 87%, again the highest of any vegetable. Chemical pesticide use was 43%.
The threshold data is even more striking. Among all households that produced more than 100 kilograms of tomatoes, which represents the more commercially oriented producers, 100% used both fertilisers and pesticides. There is not a single household in the commercial tomato farming category that is not applying both.
By contrast, for African nightshade, the most commonly grown vegetable in the study, chemical pesticide use was 14%. For amaranth, 10%. For sweet potato leaves, 5%. For pumpkin leaves, 0%. Tomatoes occupy a different tier of chemical intensity from every other vegetable in the system.
What the Food Safety Research Found
The CGIAR programme’s companion research brief on food safety, titled A Dual Threat: Postharvest Losses and Food Safety Issues in Tanzania’s Markets in Arusha and Kilimanjaro, found that chemical and microbial contamination of fresh produce are major food safety concerns in northern Tanzania. It noted limited knowledge and investment in food safety facilities across most markets, and enforcement difficulties in informal markets despite existing regulations.
The two briefs together paint a picture of a value chain in which the most chemically intensive crop is also the most commercially oriented, moving from farm to market at scale with limited monitoring of the chemical residues it may carry. This does not mean that tomatoes in Arusha and Kilimanjaro are unsafe. It means that the question of their safety has not been systematically answered, and the baseline data suggests it should be.
The Integrated Pest Management Opportunity
The FRESH end-to-end intervention’s supply-side components include training on safe and sustainable vegetable production, explicitly including integrated pest management. The brief on increasing safe vegetable production found that where good agricultural practices including IPM were applied, chemical pesticide application frequency decreased by 30% for tomatoes while yields increased by 144%.
This is the intervention’s proposition: that better farming practices can simultaneously reduce chemical input use, improve yields, and produce safer vegetables. The baseline data makes clear what that proposition is working against. Tomato farmers in the study area are using chemical pesticides at 43% overall, and at effectively 100% among commercial-scale producers. The intervention needs to demonstrate that IPM is not just environmentally preferable but commercially viable, meaning it protects yields at least as well as the current chemical regime while reducing residue risk.
The Arusha-Kilimanjaro Divide on Tomato Inputs
Regional differences in tomato input use are modest but present. Fertiliser use was 92% in Arusha and 100% in Kilimanjaro. Inorganic fertiliser use was 84% in Arusha and 79% in Kilimanjaro. Pesticide use was 87% in both regions. Chemical pesticide use was 44% in Arusha and 41% in Kilimanjaro. The chemical intensity of tomato farming is high and consistent across both study regions.
Improved seed use for tomatoes was 63% in Arusha and 83% in Kilimanjaro, a notable reversal of the usual pattern where Arusha households showed higher adoption of improved varieties for most other vegetables. This suggests that tomato seed systems are functioning reasonably well in Kilimanjaro, a region where the crop is less commonly grown but where those who do grow it are investing appropriately in variety quality.
A Food Safety Agenda for the Evaluation
The endline evaluation of the FRESH approach will assess impact on household vegetable production and fruit and vegetable intake among women of reproductive age. It will not, based on the evaluation design described in Research Brief 1, comprehensively assess pesticide residue levels in market vegetables. This is a gap that the food systems community in Tanzania should consider addressing through complementary research.
Increasing production and consumption of vegetables is a public health priority. But the health benefits of vegetable consumption depend on the vegetables being safe. The baseline data from the FRESH evaluation has shown that the most commercially important vegetable in northern Tanzania’s smallholder system is also the one with the heaviest chemical footprint. That finding deserves to sit at the centre of the programme’s food safety conversation, not at its margins.