By Umar Nsubuga
Tomatoes are among the most popular crops grown by farmers due to their high demand and versatility in cooking. However, they are prone to numerous diseases and pests that can significantly reduce yield and quality.
Gideon Zakke, an agronomist, and Joseph Bukenya, a seasoned tomato farmer, share their expertise on how to protect tomatoes from these challenges and ensure a healthy, bountiful harvest.
Understanding common tomato diseases
Blight (early and late)
Symptoms: Yellowing leaves, dark spots, and wilting of plants.
Cause: Fungal infections often thrive in humid conditions.
Control: Use resistant tomato varieties, practice crop rotation, and apply fungicides like copper-based solutions. Ensuring proper spacing between plants can improve air circulation, reducing fungal spread.
Powdery mildew
Symptoms: White, powdery spots on leaves and stems.
Cause: Fungal spores spread quickly in warm, dry conditions.
Control: Apply sulfur-based fungicides and avoid overhead watering.
Regularly inspect plants and remove infected leaves to stop the spread.
Bacterial wilt
Symptoms: Sudden wilting of healthy-looking plants and browning of stems.
Cause: Soil-borne bacteria.
Control: Ensure proper soil drainage and sterilise tools to avoid contamination. Crop rotation with non-susceptible crops like maize can reduce bacterial buildup in the soil.
Tomato mosaic virus
Symptoms: Stunted growth, mottled leaves, and poor fruit development.
Cause: Virus spread through infected plants and contaminated tools.
Control: Remove and destroy infected plants immediately. Always wash hands and sanitize tools before handling healthy plants.
Dealing with tomato pests
Tomato hornworms
Symptoms: Large green worms devouring leaves and fruits.
Control: Handpick the worms off plants or introduce natural predators like ladybirds. Applying organic pesticides like neem oil can also help.
Aphids
Symptoms: Tiny insects clustering on leaves and stems, causing curling and yellowing.
Control: Spray plants with soapy water or use insecticidal soap. Attract beneficial insects like lacewings, which feed on aphids.
Whiteflies
Symptoms: White, moth-like insects on the underside of leaves, leading to yellowing and stunted growth.
Control: Use yellow sticky traps to monitor and catch whiteflies. Spray neem oil or other organic insecticides to control infestations.
Cutworms
Symptoms: Seedlings cut off at the base, causing plant death.
Control: Place collars made of cardboard or plastic around seedlings to prevent cutworms from reaching the stems. Keep the soil free from weeds, which may harbor larvae.
Preventive measures
Crop rotation
Avoid planting tomatoes in the same spot every season. Rotating crops with non-host plants like beans or maize reduces the risk of soil-borne diseases and pests.
Healthy soil management:
Use well-drained, nutrient-rich soil to promote plant health. Adding organic matter such as compost improves soil structure and supports beneficial microbes that combat harmful pathogens.
Proper watering
Water at the base of plants to keep leaves dry and reduce fungal diseases. Avoid overwatering, which can lead to root rot and other problems.
Mulching
Applying mulch around plants helps regulate soil temperature, retain moisture, and prevent pests like cutworms from accessing the plants.
Integrated Pest Management (IPM)
IPM combines multiple strategies for effective pest and disease control.
Zakke emphasises the importance of observing plants regularly to detect issues early. Using natural predators, organic pesticides, and resistant tomato varieties as part of IPM minimizes chemical use and supports a sustainable approach to farming.
Tips from Joseph Bukenya
As a farmer who has dealt with various tomato challenges, Bukenya advises the following:
Start with quality seeds: Healthy seeds or seedlings are less likely to suffer from diseases and pests. Purchase seeds from reputable suppliers.
Prune regularly: Removing lower leaves improves air circulation and reduces disease risk.
Monitor and act quickly: Inspect your plants daily. If you spot pests or diseases, take action immediately to prevent their spread.
