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Tomato Cyst Eelworms



P_potcysteel

Tomato Cyst Eelworms

Usually appear in

Spring to Autumn.


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Caused By:-     Two Nematodes of the Heterodera Genus

Description

Cysts of yellow potato cyst nematode Picture by Bonsak Hammeraas, Bioforsk - Norwegian Institute for Agricultural and Environmental Research, Bugwood.org.
The Tomato Cyst Eelworms are the same two eelworms that are known as Potato Cyst Eelworm. They are Heterodera rostochiensis the golden eelworm and Heterodera pallida the white eelworm.
It is very difficult to distinguish between both species and identification is only important when choosing resistant varieties of tomatoes.
The majority of eelworms or nematodes are microscopic pest and can only be seen using a microscope or magnifying glass. The potato eelworm cysts can survive in the soil for up to 20 years in the absence of any potato crop. It tends to be common on allotments, where potatoes and tomatoes are often grown without using a crop rotation.
They appear as spherical white, yellow or brown cysts, which develop from mid-July to mid-August, up to 1mm in diameter can be seen on the roots if the plants are carefully dug up. These are the swollen bodies or cysts of the female eelworms and each contains up to 600 eggs.
These cysts hatch when stimulated by chemicals released by Solanum species e.g. tomato, aubergine and, occasionally, weeds such as bittersweet (Solatium dulcamara) when the 200-600 larvae are released in the soil. If the larvae do not find a Solanum root they eventually die. When they find the roots of the Solanum plant they will invade them feeding and developing in the roots of the growing plant.
Males remain worm-like and swim off into the soil when mature. Females grow and swell within the root to erupt through the root wall, whilst the head remains embedded in the root. When mature they release a chemical to attract the males. After mating the body wall of the female starts to tan and harden, forming the resistant cyst which protects the fertilised eggs within. Eventually the female dies and falls of the roots, or is dislodged when the plants are lifted. These can be wind blown or transferred to other sites by dirty equipment or soil.
Infected plants will tend to die back early, sometimes in patches, and yields will be reduced. Where soil is severely infested, growth and yield is minimal. Tomato crops can cope with low level infestation without showing any visible signs.
In the UK there appear to be a North-South divide in the appearance of cyst eelworms, with the white cyst eelworm G. pallid being the mostly encountered north of Yorkshire and Lancashire, with the golden cyst eelworm G. rostochiensis predominating to the south.
Any tomato fruits that are formed will be normal, but reduced in quantity and size.
Pictures from Wikimedia Commons.
See also these other Eelworms CHAFER GRUBS, CHRYSANTHEMUM EELWORM, DIEBACK, EELWORMS, ENCHYTRAEID WORMS, IRIS BORER CATERPILLARS, LEAF AND BUD EELWORM, LEATHERJACKETS, LILY VIRUSES, NUT WEEVIL, ONION EELWORM, NARCISSUS EELWORM, PEA AND LEAF POD SPOT, PHLOX EELWORM, POTATO CYST EELWORM, ROOT KNOT EELWORMS, SLUGS, SNAILS, Stem and Bulb Eelworm, VINE WEEVIL, WILTING, WIREWORM, WORMS.


Control

Infestations of Potato Cyst Eelworm can be predicted by monitoring soil in advance of planting. Check in July/early August by carefully expose the roots of a Solanum plant and look for pinhead sized white, yellow or brown cysts on the roots. A magnifying glass will help.
Potato Cyst Eelworm can be kept under control by the use of good hygiene, crop rotations, pesticides and using tomato varieties which have resistance to eelworms.
Nematicides and soil fumigants are available but expensive and toxic. Accurate and proper application is essential, therefore the manufacturers instructions must be followed to achieve control.
Water from the base of the plant rather than spraying potatoes.
For organic farmers a copper based fungicide is often used.
Use compost and composted manure to improved the soil.
No-dig growing is said to reduce the effects of eelworm on potatoes.
Use a 4 year or longer crop rotation where eelworm is a problem. Tomatoes are also susceptible.
Removal and burning of infected plant debris, and eradication of weed hosts to reduce the number of eelworms that can infect the plants.
Planting agricultural mustard may help to reduce eelworm by hardening their cysts and preventing them from emerging on time, confusing their breeding cycle. Be careful though if you have club root because mustard is a brassica and mustard green manure can further spread the disease.
Plant resistant varieties of tomatoes.

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