The good temperatures recorded in greenhouse vegetable production areas in southern Spain have led to the spread of the Tomato Yellow Leaf Curl Virus (TYLCV) in tomato crops, according to the Alert and Phytosanitary Information System (RAIF) of the Government of Andalusia.
Its vector, the whitefly (Bemisia tabaci), has been detected in all greenhouses sampled, regardless of the phenological stage they were in. It has been found in 1 out of every 10 plants in those where the harvest is only just starting, while in greenhouses where the harvest is in full swing, it has been detected in 1 out of every 8 plants.
Low levels
Although samples indicate low levels in the presence of whiteflies, symptoms caused by the TYLCV virus have been detected in all sampled greenhouses and at slightly higher levels than what would be normal for this time of the year.
One of the most important predators (biological control organism) used to control the whitefly population is the Nesidiocoris tenuis, which is present in all sampled greenhouses and in 1 out of every 3 plants. Its presence, however, is expected to drop as temperatures continue going down.
Measures
Although the virus' presence is not alarming for now, it is advisable to take measures to prevent the presence of the vector (whitefly) and reduce the spread of the virus from plant to plant .
It is advisable to set up screens on the greenhouse side and overhead openings and doors, as well as to monitor and control their state of repair, especially of those facing prevailing winds.
Protect the plants during their early vegetative stages.
Remove plants that are deeply affected.
Create the right conditions for the growth of populations of beneficial insects, rationalising the use of pesticides.
Remove and destroy all pruning waste.
Pull up and immediately remove all plants affected by the virus and those surrounding them as soon as the first symptoms are detected.