Protecting Your Crops from Common Pests and Diseases in Nigeria

Pest and disease losses are estimated to reduce Nigerian crop yields by 20–40 percent annually. Early identification and integrated management can recover most of that loss without excessive chemical inputs.

Maize: Fall Armyworm

Fall Armyworm (Spodoptera frugiperda) arrived in West Africa in 2016 and is now the most destructive maize pest on the continent. Look for ragged holes in the whorl of young plants and dark frass (caterpillar droppings) in the leaf axils. At first infestation, apply sand or ash into the whorl. For severe attacks, approved biopesticides (Bt-based products) are effective and registered in Nigeria.

Tomato: Early and Late Blight

Both blights are fungal diseases that spread rapidly in humid conditions. Early blight (Alternaria solani) appears as dark brown spots with concentric rings on lower leaves. Late blight (Phytophthora infestans) causes water-soaked lesions that spread within days. Prevention is far more effective than cure: use certified disease-free seeds, space plants to allow airflow, and avoid overhead irrigation. Apply copper-based fungicides preventatively at the start of the rainy season.

Cassava: Mosaic Virus

Cassava mosaic disease is transmitted by whiteflies and causes yellow, distorted leaves and yield losses of 20–80 percent. Use certified virus-free cuttings from IITA or state agricultural development programmes. If infected plants appear, remove and burn them immediately to prevent whitefly spread.

Cowpea: Aphids and Pod Borers

Aphids cluster on growing tips and undersides of young leaves, causing curling and stunting. A simple soapy water spray (50ml liquid soap per 10 litres water) controls light infestations. Maruca pod borer is the most damaging cowpea pest — plant early-maturing varieties where possible to reduce exposure.

General Prevention Principles

1. **Use certified seeds**: Most disease-resistant varieties are available through NASC-accredited seed companies.
2. **Practise field hygiene**: Remove crop debris after harvest. It harbours overwintering pests and disease spores.
3. **Scout regularly**: Walk your fields twice a week during the growing season. Early detection is worth more than any chemical.
4. **Rotate crops**: As covered in our crop rotation guide, rotation disrupts host-specific pest populations.
5. **Record every spray**: Know what you applied, when, and whether it worked. This prevents inappropriate repeat applications and helps you refine your programme.