Viral diseases in tomatoes can cause serious damage in greenhouses

Viral diseases of greenhouse tomatoes in North Carolina occasionally cause serious damage and large economic loss. The amount of loss can vary depending on the virus disease involved, the variety of tomato, the age of the plant at infection time, the temperature during disease development, the presence of other diseases, and the extent that viruses have spread in the planting. The dense plant spacing, closed environment, and frequent mechanical contact that is inherent to greenhouse tomato production increase the chances of a viral disease outbreak. Keep in mind that symptoms will vary by strain of virus, age and health of host upon infection, and environmental conditions. The first step in controlling a disease is identifying the causal agent.

Though it has not yet been detected in North Carolina, the Tomato brown rugose fruit virus (ToBRFV) was first detected and eradicated in the United States in 2018 and its spread is currently being closely monitored by the USDA Animal and Plant Health Inspection Service (USDA-APHIS). Peppers, eggplants, tomatoes, and cut-leaf ground cherry are all hosts of the virus. It is transmitted by seed and spreads easily via mechanical contact. Symptoms often do not show up until fruit begins to ripen, but symptoms may include mosaic patterns on leaves, leaf narrowing, necrotic pedicles, calyces, and petioles, and smaller, discolored fruit that ripens later.
Control of viruses on tomato requires a complete program that is implemented all year.
 
Resistant varieties. When possible, plant resistant or tolerant varieties. There are varieties that have varying levels of resistance or tolerance to certain strains of TMV and TSWV.

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Publication date: Thu 26 Aug 2021