Tomatoes Pests and Diseases

Tomatoes Pests and Diseases

Blossom end rot

tomatoes pests and diseases - tomato blossom end rot Typical symptoms: A circular, sunken, dark-coloured patch can be found at the blossom end of affected tomato fruits. These symptoms are due to a shortage of calcium in the fruit and this deficiency is caused by an irregular supply of water.

Prevention and treatment: Ensure that plants are never short of water, especially those grown in pots and growing bags.

Cold nights

Typical symptoms: Leaves curl up; growth otherwise normal. This is a harmless condition caused by wide differences in day and night temperatures.

Prevention and treatment: Protect tender plants.

Foot and root rots (various fungal diseases)

Typical symptoms: Plant wilts and the foliage may become yellowed. The stem base and/or roots rot.

Prevention and treatment: Correct conditions such as poor soil structure or drainage that could stress plants. Use a crop rotation. Greenhouse tomatoes may be saved by earthing up stems with clean soil or compost. Remove and burn badly infected plants.

Fruit splitting

Typical symptoms: Tomato fruits split.

Prevention and treatment: See Plant Disorders – Understanding the Problem

Hormone weedkiller damage

Typical symptoms: Leaves are narrow and twisted; stems twist in a spiral. Fruit may be hollow and seedless.

Prevention and treatment: See Plant Disorders – Understanding the Problem

Magnesium deficiency

Typical symptoms: Orangish-yellow colour develops between leaf veins, on the lower leaves first.

Prevention and treatment: See Plant Mineral Deficiencies

Potato blight (Phytophthora infestans)

This is the same disease that attacks potatoes.

Typical symptoms: Dark patches appear on the leaves and the stems may collapse. A tough, dry, brown rot can develop on the fruit, although this may not become obvious until after it has been picked.

Prevention and treatment: There is little that can be done against this disease. In a greenhouse, increased ventilation may help to reduce the spread. Bordeaux mixture may be used to protect plants (see Growing Potatoes – Pests and Diseases).

Red spider mite, glasshouse (Tetranychus urticae)

Typical symptoms: Leaves turn yellowish-bronze and die off. With the aid of a magnifying lens, tiny green mites can be seen on the underside of leaves. A severe attack may cause the leaves to wither and die.

Prevention and treatment: Give plants good growing conditions. Do not let the soil or the atmosphere in the greenhouse become too dry. The biological control agent Phytoseiulus persimilis can be introduced to control this pest (see Plant Pests and Diseases – Biological Control). Check new plants before bringing them into the greenhouse; clean the greenhouse out thoroughly every autumn.

Virus diseases

Typical symptoms: Symptoms including stunting, distortion or unusual coloration of leaves.

Prevention and treatment: See Plant Diseases – Understanding the Problem

Whitefly, glasshouse (Trialeurodes vaporariorum)

Typical symptoms: Leaves are covered in small white insects that fly up when disturbed. Yellow scales are visible on the underside of leaves. Black sooty moulds and sticky deposits may be present.

Prevention and treatment: Use sticky yellow traps (see Garden Pests and Diseases – Barriers and Traps) to monitor the appearance of whitefly in the greenhouse; take action as soon as they are seen. Suck up the adult flies using a portable vacuum cleaner or spray with insecticidal soap. The biological control agent Encarsia formosa can be introduced (see Plant Pests and Diseases – Biological Control). Always check new plants for whitefly before bringing them into the greenhouse.

Wilts (various fungal diseases)

Typical symptoms: Leaves wilt but may recover at night initially. Brown streaks are visible in the stem if it is cut well above soil level.

Prevention and treatment: See How to Treat Common Plant Diseases

02. February 2011 by Dave Pinkney
Categories: Kitchen Garden, Organic Gardening, Pests and Diseases, Salads | Tags: , , | Comments Off on Tomatoes Pests and Diseases


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