Tomato pests

Page last updated: Thursday, 23 January 2014 - 4:25pm

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Various insects, nematodes and mite pests can damage tomato crops in the home garden and nematodes, russet mites and budworms can be especially destructive. The plants can be damaged at all stages of growth.

This article describes some of the more important pests and methods for their control.

Exotic pest

The exotic Queensland fruit fly was first detected in Western Australia in green tomatoes in 1989 and subsequently eradicated.

The Mediterranean fruit fly sometimes attacks vine ripened tomatoes in suburban backyards. Spray with a splash bait containing spinosad weekly to reduce pest numbers. Place insect exclusion bags or sleeves, which are made from waxed paper or insect netting, over the green fruits.

Common pests

Aphids

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Aphids are most commonly seen in spring and autumn when the weather is mild and humid. They are small, soft-bodied, green, grey or black insects with thin legs. Aphids may be winged or wingless and are usually slow moving. The insects cluster on the tips of the plant shoots. By sucking the sap they reduce the vigour of the plants. Aphids can also be carriers of virus disease which can severely reduce yields and quality.

In a healthy garden aphids will be controlled by beneficial insects, but these normally take two weeks to build to sufficient numbers to reduce aphid populations. Aphids can be squashed with finger and thumb or reduced by spraying soapy water or knocked from the plants using a water jet from the hose.

Organic controls include horticultural (potassium) soap, horticultural oil and rotenone dust (derris). Imidacloprid is a low toxicity systemic. Other insecticides include dimethoate, cyfluthrin, tau-fluvalinate or pyrethrum and piperonyl butoxide.

Budworm

These caterpillars are tough-skinned, brown, reddish or green and are about 40mm long when fully grown. They have irregular dark stripes on their back and a lighter stripe on each side of the body. Budworms bore holes in the fruit.

These pests are hard to kill and it is important that any infestation is tackled early in the season before the fruit becomes vulnerable to attack. They are common in summer.

The caterpillars pupate in the soil. The moths have light brown forewings and the hind wings have a darker brown margin on the trailing edge. They lay small white visible eggs on the plants, which are a sign of a pending attack.

Pick off the caterpillars or spray early as the small caterpillars are easier to kill and at this stage have caused less damage.

Bacillus thuringiensis is an organic spray. Spinosad (low toxicity), pyrethrin, cyfluthrin or tau-fluvalinate and fluvalinate can also be used on caterpillars.