Tomato Pest And Disease Problems

7 Mar

Tomatoes are in the potato family, and are susceptible to tens, if not hundreds of pest and disease problems; however, that should not stop any tomato loving gardener from harvesting buckets of healthy tomatoes. The key is to learn how to prevent, diagnose and treat tomato problems.

Tomato Disease Prevention

Banishing disease starts with healthy growing practices. Preparing the soil, watering properly, and feeding appropriately are all keys to tomato disease prevention. Tomatoes like a well draining soil filled with lots of organic matter. Tomato roots penetrate deeply into the soil, helping to stabilize plants and take up water. With well-prepared soil, watering deeply every 2-4 days, will allow the tomato plant to have enough water, without putting the plant at risk of problems of overly “wet feet.” Always water in the morning, so plant leaves have time to dry during the day. Leaves are a perfect spot for disease incubation, and water ripens those conditions even more. Prune your plants to provide air flow through the leaves and branches, which will also aid drying time. Ensure that your tomato plants receive proper nutrition by conducting a soil test, and treating the soil according to the results. All of these practices will give your plants a good start fighting off diseases and pests.

Diagnosing Tomato Pests and Diseases

If all of your well-intentioned cultivation practices have not stopped your plants from succumbing to a problem, then it’s time for diagnosis. Tomatoes can suffer from pest problems, nutrition problems, viral, bacterial and fungal problems.

spider mite damage on tomato

spider mite damage on tomatoes

Pest damage to tomato plants causes visible physical changes. Cutworms actually cut off the plant from its root system, causing the plant to wilt and die. Aphid damage results in sticky residue on the plant. Aside from the damage they inflict, you can often see the pest itself on the plant. Caterpillars bury into fruit and eat it, causing fruit to rot. Whiteflies and spider mites are visible on the leaves. Diagnosing pest problems is easier than other problems because most pests can be observed on the plant.

Nutrition problems manifest in several areas of the plant. Tomatoes absorb a wide variety of nutrients, minerals and trace elements from garden soil. Deficiencies in each nutrient result in specific symptoms in the plant. Excess nitrogen causes deep green, lush, leafy plants with little fruit. Nitrogen deficiency causes yellowing of lower leaves. Calcium deficiency causes blossom end rot, a common problem on tomato fruit characterized by yellow, leathery spots that spread into black, rotting patches on the blossom end of the fruit. (The end away from the stem.) Nutrition problems can be seasonal, or soil related. A soil test helps determine what nutrients are lacking in the soil. If all nutrients are in the soil, factors such as overly wet or cold soil can make it more difficult for plants to absorb nutrients.

Viruses, bacteria and fungus all cause tomato diseases and problems. Wilts, damping off, leaf spots, mildew, fruit rot, cankers, and leaf mosaic problems are all common tomato problems caused by a cocktail of tiny organisms. Each problem shows in the tomato in different ways. Leaf mosaic viruses show up in leaves, causing mosaic-like patterns. Cankers are growths on stems, leaves or fruit. Root rot often shows up in the leaves of the plant, as they shrivel and die from not having enough water.

For a comprehensive, pictorial guide on diagnosing and controlling tomato plant pests and diseases, consult our extensive nutrition, pest and disease chapters in How to Grow Tasty Juicy Tomatoes.