Preventing Tomato Plant Problems - Diseases and Pests

May 28, 2011
Clarice Cook

Yellow, mottled leaves signals Fusarium Wilt - Image: Clarice Cook

Buying disease resistant tomato plants, good gardening hygiene and maintenance is the key to abating problems in the garden.

In planting, harvesting and working with tomatoes, a lot of tomato problems can be solved by cleansing hands and tools with antibacterial soap, before and after contact. Being kind to and encouraging insects and reptiles and birds that feed on tomato pest larvae, such as the nasty horn worm, is also helpful. Preventing disease from the beginning saves a lot of work later on.

Preventing Diseases of the Tomato Plant

Planting disease resistance varieties will prevent many wilting, yellowing and dying of leaves from lower branches upward and finally death of the whole plant. The Fusarium wilt disease is one such enemy that can be stopped by buying wisely.

Leaf spot and early blight is caused by the same fungus that attacks potato plants. The symptoms are dark-brown circular spots on the leaves. This disease may be controlled by spraying with a 3-5-50 Bordeaux mixture or by dusting with 20-80 copper lime dust. This should be done with caution and on a day when it is not windy. To prevent spread of the disease organisms, do not cultivate or walk among the plants during wet weather.

Blossom end rot are the water soaked areas on the blossom ends of fruits that later turn black is due to unfavorable environment conditions. The soil around tomato plants should be moist, but not of "mud pie" content. If the soil drains excess water away, the tomato plants can draw nutrients without getting water logged.

The virus disease, Mosaic (yellowing, mottling leaves and stunted growth, are serious and can spread quickly. Pull these plants with gloves on and burn away from the garden.

Destroying Pests of the Tomato Plant

Cut worms can be kept away from tomato plants by cutting the bottoms from paper or foam cups and feeding the plants through them, or wrapping the stalks in paper, half below the ground. However, there are safe mixtures available at the greenhouses to kill the eggs and adult worms throughout the garden. Spread this mixture at night because cut worms are night feeders.

The cut worm is the larvae or caterpillars of many species of moths. The small larvae winter in the soil under plant debris. In the spring the smooth, dull gray, green or brown, caterpillars emerge to clean up tender plants as they are set out. The plants are cut off near the surface or some species crawl up the plants and eat the leaves. In early summer the caterpillars develop into moths to lay eggs under the debris after harvest. After harvest, clean off the garden spot and till to prevent return of the moths the following year.

To deter the ugly, nasty horned tomato worm moth from laying eggs on or near the plants, check with the local extension service or greenhouse for a mixture to kill the larvae.

A moth with a wing span of 4 to 5 inches lays the larvae for the tomato horn worm that burrows in the ground in early morning and comes back out at night to destroy the leaves and sometimes eats the fruit of the tomato plant. The large caterpillar (up to about 3") is transparent green as it consumes the plant. Signs of small, bead like fecus is apparent at the base of the plant and near the hole. Some have heard a clicking noise in the night as the worm feeds. Using gloves, go out at dusk and pick the worms off and smash them for immediate relief for the plants.