Preventing tomato spotted wilt

Once this disease arrives on a tomato land, it is very difficult to get rid of. The problem is made worse if weeds are nearby, as many weed species are susceptible to attack by the virus, says Bill Kerr.

- Bill Kerr

Spotted wilt is a viral disease that affects numerous species, including many weeds. It is this that makes the disease such a threat.

The vector is the western flower thrip (Frankliniella occidentalis). Controlling this pest is not always easy; it’s much better to make sure there are no infected weeds adjoining the land in the off season, as these can keep the virus going until the next crop is planted.

My tomatoes and sweet peppers suffered a lot of damage from spotted wilt until I realised that a few weed species on the verges of the land were infected. I found symptoms of the virus on prickly lettuce (Lactuca serriola), small mallow (Malva parviflora), sowthistle (Sonchus oleraceus), chickweed (