Friday, 26 September 2008

Tomato Pest And Disease Problems - Preventing, Diagnosing And Treating

Tomatoes are notoriously picky plants. Tomatoes are in the potato family, which makes them 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

Disease prevention in tomato plants 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 and infrequently-every 4-6 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 you must diagnose the problem. Tomatoes can suffer from pest problems, nutrition problems, viral, bacterial and fungal problems.

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 in tomato plants 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 tomato plant pests and diseases, consult How to Grow Tasty Juicy Tomatoes (available from

Treating Tomato Pest and Disease Problems

The phrase: an ounce of prevention is worth a pound of cure definitely applies to tomato growing. As earlier related, properly caring for tomato plants and their soil prevents many problems. However, should your plants fall prey to a problem, there are many ways to treat.

First, correctly diagnose the problem. Once diagnosis is certain, follow procedures related to the particular problem. Many plant problems can be alleviated by changing gardening techniques. Plants that are stressed are more susceptible to pest and disease problems. Examine watering, mulching, and feeding practices. If those techniques are in balance, many pest and disease problems will go away. Nutrition deficiencies may be corrected by adding correct nutrients to the soil in easily accessible forms. Some nutrients are best delivered as leaf or soil drenches, while others work well in time-release granular applications. Pest problems can be corrected with beneficial insects, changes in gardening techniques, and insecticides-both synthetic and organic. Viral, bacterial and fungal problems can also be treated with a combination of gardening techniques and soil and plant drenches and sprays. Safety is an important consideration when applying any sort of pesticide. Read the label carefully and follow all directions. More is not better when pesticides are concerned.

While all of this information can seem daunting, tomato growing is a rewarding hobby. Keep a good reference on hand, and whenever your plants are under the weather, open the book and identify the problem. How to Grow Juicy Tasty Tomatoes contains over 260 colored photos of diseases, pests and common nutrition deficiencies and is a must-have for any top-notch tomato grower!

If you want more detailed tomato garden advice and tips from a world horticultural expert, visit

1 comment:

Thomas said...

I've found that fortifying the plant ahead of time with Scorpion Juice helps it to fight off pests and diseases, kind of like taking vitamin C before cold and flu season hits.

It's one of the things Advanced Nutrients makes - worth every penny.

Also, I highly recommend BT for caterpillars. It's a bacteria that's only harmful to them and works better than anything else I've found.