April 2002. Thailand asked what might have caused the speckling to the leaves of tomato, grown in ‘protected cultivation’, presumably a screen house. The leaves become corky, and the spots turn necrotic.

In response, members suggested insect or mite damage caused when the leaves were much younger. It is possible that there is fungal infection too. It was asked whether there was any fine webbing on the underside. It is most likely caused by either spider mites (Tetranychidae), thrips (Thysanoptera) or possibly leafhoppers (Cicadellidae). Examine the very young leaves and buds – quickly dip them in soapy water to wash out any animals. Preserve anything that is found in 70% ethanol.