Tomatoes are among the most popular and widely produced vegetables in Kenya. Successful production of this high-value vegetable provides high income to smallholder farmers and has dramatically improved several livelihoods.
However, tomato farming is also a highly demanding task because of the frequent occurrence of pests and diseases and the consequent reduction of the crop’s productivity and profitability. The notorious problems include whiteflies, leafminers, Tuta absoluta, thrips, spider mites, and fruit worms.
The major tomato diseases are bacterial and Fusarium wilt, early and late blight, powdery mildew, and viral infections. Because of this, tomato farmers invest heavily in agrochemicals, including pesticides and synthetic fertilizers, to protect the crop and improve production.
Although helpful in reducing crop damage, chemical pesticides only provide a short-term solution to control pests and diseases. Moreover, because of the numerous challenges, farmers have resorted to a calendar-based application system of broad-spectrum pesticides.
A recent analysis of pesticide residues on tomatoes produced in Kenya revealed that some commonly used chemicals are highly toxic and have potential chronic health and environmental effects. Besides, most pesticide concentrations exceed the acceptable maximum residue level (see attached image).
Organic tomato farming presents a promising alternative to chemical pesticides. It encourages the production of safe and healthy tomatoes through organic and ecologically sustainable agricultural systems.
The first step towards organic tomato production is the management of soil fertility for better crop nutrition. Rich organic soils are achieved by the addition of animal manure and compost.
Instead of frequent pesticide applications, farmers are encouraged to adopt good agricultural practices to prevent or reduce incidences of pests and diseases. These include:
- Transplanting of pest-free seedlings
- Regular crop monitoring to detect early infestations and promote prompt control.
- Use of commercial and homemade organic pesticides to control severe infestations. Examples include soap sprays, wood ash, flour preparations, neem extracts, onion, garlic, and chili pepper.
- Use of commercially available copper-based and Sulphur pesticides to control the significant tomato diseases.
- Proper weed control.
- Intercropping tomato with insect-repellent crops, e.g., garlic, onions, and basil.
- Embrace natural enemies to control insect pests such as predators and parasitic wasps.
- Adopting companion planting to foster biodiversity and ecological balance of pests and their natural enemies.
- Tomato crop rotation with unrelated crops like legumes, cereals, and brassicas.
A calculated integration of these practices will yield huge agronomic benefits such as enhanced soil fertility, reduced crop damages, and increased tomato yields and farmers’ income.
An organic tomato farming approach will also reduce the overdependence on chemical pesticides and contribute to enhanced human and environmental health.
Grace Kinyanjui is a PhD student pursuing a degree in applied entomology.