Nematodes in Lettuce – How to Treat Lettuce with Nematodes

Nematodes in lettuce can be very destructive, causing a variety of symptoms depending on the variety of nematodes present. However, in general, if this pest infests your lettuce crop, it will cause damage, reduce yields and may even wipe out your entire crop for a season.

What are nematodes?

Nematodes are parasites that attack plants. They are microscopically small roundworms, so you can’t see them, and they feed on the roots of plants. Nematodes in lettuce infestations can be one or more of many varieties. There are about 50 species of nematodes that can feast on lettuce, depending on the geographical location.

Nematode damage to lettuce

The type of damage that nematodes cause in lettuce depends on the species causing the infestation. One type of nematode that usually attacks lettuce is the root ball nematode. This type of nematode causes atrophy, uneven growth and delayed maturity, but the characteristic sign of the root ball nematode is the thickening or gills on the roots of the lettuce plant.

Another type of nematode that can infest lettuce is called the needle nematode. It gives seedlings a wilted appearance and can turn lettuce leaves gray. The needle nematode also causes the roots to swell at their tips or even die.

In general, lettuces affected by nematodes do not grow well or develop smaller heads, and may also show leaf discolouration.

Lettuce Nematode Control

Nematodes can be difficult to control or eradicate, but a combination of cultural, biological and chemical management can have a great impact.

Crop rotation has been shown to be useful, for example. Rotating areas of the garden between lettuce and a crop, such as corn, that does not harbour nematodes can help keep them out of the soil. The use of cover crops, such as oats, wheat or rye, that do not harbour nematodes can also be useful.

If you have had nematodes in your garden, it is important to thoroughly clean all garden tools to prevent their spread.

To help your lettuce crop that is stunted and suspected of being infested with nematodes, use extra fertilizer and water. Nematodes cause stunted growth because they prevent plants from absorbing enough water or nutrients. Adding nutrients and water can help save a crop in trouble.

Finally, chemical means can help control lettuce nematodes, but are most effective when combined with some of the above strategies. Nematicides are pesticides specifically designed to kill nematodes. However, these pesticides are harmful to human health, so if you decide to use them, do so with the help of an expert and be very careful.