Root-knot nematode
The root knot nematode or eelworm is a minute worm that cannot be seen with the naked eye.
It attacks most vegetables and may severely damage tomatoes. Damage is seen as enlarged swellings on the roots and wilting of the plants.
Gardeners can use solarisation (using a clear plastic sheet to heat the soil in summer for one month) or clean soil using a biofumigant by growing a crop of mustard or marigolds. For further information read the DAFWA web article 'Nematodes'.
Thrips
Thrips do not cause severe injury to tomatoes, but are carriers of the spotted wilt virus disease, which seriously damages tomato plants.
Thrips are small, yellow, green, grey, or black torpedo-shaped insects with or without feathery wings, which are usually folded along the back. They have sucking mouthparts which slit the surface and withdraw the sap of the leaves, fruit, and flowers. Routine spraying is essential where spotted wilt virus is a problem. This helps to keep thrips to a minimum. Spraying is most important in the early stages of plant growth.
When the infestation becomes severe they are almost impossible to control as they are present in such large numbers. They are also resistant to many sprays.
Control with dustings of sulfur or thorough spraying with good coverage of the undersides of the leaves using horticultural soap, imidacloprid, cyfluthrin, diazinon or dimethoate.
Tomato russet mite or tomato mite
These mites are most severe in summer and autumn. They are cream and torpedo-shaped and much smaller than two-spotted mites and can only be seen with a hand lens with a magnification of 20 times. Damage symptoms include bronzing of the stem, withering of the lower leaves and leathery skin on the fruit. The flavour of the fruit is also affected.
Control with horticultural (potassium) soap, dicofol or dust with sulphur.
Whitefly
Whiteflies are tiny sap-sucking insects often found on the undersides of leaves. Whitefly adults resemble very small moths and fly in large numbers when disturbed. The young stages have no wings and look more like scale insects. They may be difficult to control. Insects such as lace-wings, ladybirds and hoverflies will feed on whiteflies.
Sprays of horticultural (potassium) soap, bioallethrin and bioresmethrin will also help to reduce whiteflies and also leafhoppers, which are tiny leaf-sucking insects that may damage seedlings and small plants.
Unfamiliar pests
Unfamiliar pests could cause significant problems for our primary industries and environment if they were to become established in Western Australia.
So if you see an unusual pest please contact the Pest and Disease Information Service (PaDIS) on 1800 084 881 or enquiries@agric.wa.gov.au.