Protection methods
 

• During cultivation

In the nursery, it is urgent to impregnate the entire substrate with an anti-oomycetes fungicide solution ( ephy-melon ) ( e-phy Phytophthora , e-phy Pythium ). It is also necessary to limit irrigations if they have been too abundant. Good wiping of the substrate will be favored after sprinkling irrigations. If the seedlings are produced under shelter, it is advisable to promote the ventilation of the latter as much as possible and subsequently to control the climate of the greenhouse in order to avoid excess humidity. Diseased seedlings and those nearby should be removed.

During cultivation and following root attacks, phytosanitary interventions are different depending on the context:
- in soil , generally few plants are affected and no treatment is to be applied;
- out of soil (especially cucumber), fungicides can be added in the nutrient solution or locally by watering at the foot of the plants. The doses chosen must be lower in order to avoid phytotoxicity.

It should be added that aerial attacks, occurring mainly in the open field, are normally well controlled by anti-mildew treatments .

Maintain balanced fertilization and avoid stressing the plants.

Diseased plants and plant debris should be carefully removed during and at the end of cultivation, in particular root systems and rotten fruit.

• Next crop

 In the nursery, the substrate used must be healthy or disinfected . In countries where producers make it themselves, for example from sand, reclaimed earth, various composts, there is a risk of contamination. The same goes for producers who mix their purchased substrate with the aforementioned ingredients. The clods will not be placed on the ground, especially if the latter has not been disinfected. It will be better to place them on plastic wrap or on shelves. In contaminated soils that have not been disinfected, the seedbed can be soaked preventively with an anti-Oomycetes fungicide solution ( e-phy Phytophthora , e-phy Pythium ). In France, it is recommended to incorporate propamocarb HCl into the soil or to soak the clods with it.

In soil cultivation, crop rotations will be carried out with cereals and fodder grasses. Heavy and wet soils will be drained. We will add organic matter to lighten them. The plants will be planted on mounds in order to avoid water retention at the foot of the plants. The soil can be mulched. Fertilization should be balanced.

In some particularly affected soils, disinfection with a fumigant will be considered. The active ingredients conventionally used (metam-sodium, dazomet, propamocarb HCl ) and steam are effective against Pythium spp. and Phytophthora spp. In production areas where it is possible, solar disinfection of the soil (solarization) will be carried out. Rather spectacular results have been recorded, especially in certain Mediterranean countries: the soil to be disinfected is carefully prepared and moistened, then covered with a polyethylene film 35 to 50 µm thick, held in place for at least one month at a period of very sunny year. This economical method, with a broad spectrum of efficiency, makes it possible to control Oomycetes.

When planting, avoid placing the plants in soils too wet or cold . The irrigations carried out at this stage of the crop should not be excessive. A plastic mulch will be put in place to avoid subsequent contact of the fruit with the soil.

The sprinkler irrigations will not be too abundant so as not to keep the soil moist for too long.

In soil-less cultivation, before any cultivation, the irrigation circuit will be emptied and disinfected. It will also be in your best interest to replace the growing medium each year.

It will be necessary to be wary of the sanitary quality of the water used for the preparation of the nutrient solution and the irrigation of the plants, especially if it comes from an irrigation canal, a watercourse, a pelvis, etc., which may have been contaminated.

To our knowledge, no variety of melon sold in France seems to have resistance to Oomycetes.

Certain antagonist microorganisms have been tested to control some species of these chromists: Trichoderma harzianum, T. virens, Gliocladium virens, Pythium oligandrum, Pseudomonas fluorescens, Bacillus subtilis, Enterobacter cloacae, Burkholderia cepiacia e ... Their use is already effective in some countries.


* Chemical control : As the number of pesticides available for a given use is constantly changing, we advise you to always confirm your choice by consulting the e-phy site of the Ministry of Agriculture and Fisheries which is an online catalog of plant protection products and their uses, fertilizers and growing media approved in France. This also applies to all biological products based on microorganisms or natural substances.