Lowering the risk of viruses in your cucurbit crop

Viruses can be devastating to cucurbits, and you should take every precaution to prevent or reduce the damage they cause, says Bill Kerr.

- Bill Kerr

In the previous issue (FW of 27 January 2023), we listed the four viruses that attack cucurbits in South Africa, namely the cucumber mosaic virus, zucchini yellow mosaic virus, papaya ringspot virus, and watermelon mosaic virus. Their symptoms vary and only a laboratory test can determine whether your plants do, in fact, have a virus and what type it is. Prevention and treatment is the same for all types, in any case.

The source of the virus in your crop may well be a species of weed that has over-wintered in the area. When winter has passed and the weeds grow again, aphids, which can also breed up quickly, seek out the tender new growth and migrate from there into your cucurbits, taking the virus with them.