• During cultivation

As soon as you detect the very first symptoms due to Leveillula taurica , it can be recommended to eliminate quickly the first leaves attacked , taking care to put them directly in a plastic bag in order to avoid spreading spores. These affected leaves will then be removed from the crop and destroyed.

Treatments should also be carried out using one of the fungicides * authorized ( e-phy ). Care should be taken in order to cover the lower leaves and the underside of the blades well. They will be renewed by alternating chemical families with different modes of action.

We also advise you to follow a number of hygiene measures throughout the cultivation:
- limit the presence of visitors in the greenhouse in order to reduce the risks of dissemination;
- carry out a stripping of the base of the plants. This will make it possible to eliminate the first attacked leaves and will promote aeration and sunlight in the lower parts of the plants;
- control the climate of the shelters in order to reduce humidity and promote air circulation. Water condensation on the foliage should be avoided.

The plant debris will be disposed of fairly quickly parcels, both during cultivation (following different cultivation operations) and after the uprooting of plants. They will imperatively be destroyed.

• Next crop

In the open field , crop rotations fairly long can be carried out. When the plants have been produced in other production regions which may already be affected, it will be necessary to check their quality and / or to carry out an insurance fungicide treatment as soon as they arrive.

Under shelters , disinfection of structures and walls will be judicious in order to destroy the spores present. Products identical to those used for Mycovellosiella fulva may be used. Subsequently, the cultures will be carefully monitored for the very first symptoms of internal powdery mildew. In fact, the earlier the disease is detected, the more the protection methods put in place will have a chance of being effective. It is particularly difficult to stop a epidemic L. taurica growing .

Of course, all the prophylactic measures listed above will be implemented. In addition, cultivated plants or weeds likely to harbor this fungus will be eliminated from the shelters and their immediate environment.

The gene for resistance " Lv " to L. taurica , dominant and located on chromosome 12, was introgressed by back-cross of the wild species Lycopersicon chilense in the cultivated tomato. This resistance is now available in several varieties.

Some microorganisms antagonistic have been tested and have proved to be more or less effective with regard to L. taurica: Trichoderma harzianum, Ampelomyces quisqualis … The same is true for a plant extract ( Reynoutria sachalinensis ) and phosphate solutions monopotassium or potassium bicarbonate sprayed on the leaves.