Protection methods

Vertcilliosis does not currently require the implementation of special protection methods in France where this disease does not seem to be rampant on zucchini and squash. In countries where it is harmful to these productions, we can offer the recommended protection methods, especially in melon cultivation.

• During cultivation

No control method can eradicate verticillium wilt during cultivation. We can always try to block its development by adding to the base of plants or via the drip irrigation system a solution fungicidal * based on a benzimidazole still available in France, thiophanate-methyl ( e-phy ). In addition, light baths can be carried out at the hottest times of the day in order to reduce leaf wilting.

The tools used in contaminated plots must be cleaned well before serving others in healthy plots. It is the same for the wheels of tractors. Careful rinsing of this material with water will often suffice to rid it of soil and Verticillium dahliae .

Crop residues commonly buried in the soil are abundantly colonized by V. dahliae, which produces numerous microsclerotia. Their elimination limits this phenomenon and helps to reduce the inoculum left in the plots.

• Next crop

The crop rotations will prevent or delay the onset of this disease. To be effective, they will be long enough, at least 4 years, and will not involve sensitive crops such as eggplant, potato, pepper, cucurbits, strawberries. Monocots, especially cereals, do not seem to be affected by this vascular fungus. Peas, beans and cabbage could be used in the rotations as they would not favor the maintenance of the inoculum in the soil.

The destruction of certain weeds such as black nightshade and pigweed will be considered as they are hosts of V. dahliae .

Avoid planting Cucurbits, and especially melon, in too cold and damp soil, and we will ensure a manure in balanced order to avoid obtaining young plants with too succulent tissues. The irrigation should be optimized during warm periods to limit wilts.

The disinfection of the soil with a fumigant is sometimes advocated in some countries; it reveals only a partial and not very durable effectiveness, and its cost can be high. The same is true for steam disinfection. Note that no verticillium wilt use is available in general soil treatments in the database e-phy . Disinfection by solarization , recommended to fight against other soil fungi such as Rhizoctonia solani , reduces the incidence of V. dahliae . Let us add that it will be advisable not to work too deeply the disinfected grounds before the setting in culture, under penalty of causing microsclerotia to rise in the treated stratum.

Remember that thiophanate-methyl is approved for “soil treatment” use on melon ( e-phy ).

The immersion of contaminated plots for several days would help to limit the number of microsclerotia present in the soil, by reducing the quantity of oxygen available and by increasing the quantity of CO ₂ . However, this measure does not appear to reduce the incidence of the disease sufficiently to be adopted. The remaining propagules are sufficient for V. dahliae to develop on its host.

Several antagonist microorganisms have been tested with degrees of success to control V. dahliae varying on different crops: Gliocladium roseum, Glomus mosseae, Trichoderma viridae, Talaromyces flavus, Penicillium oxalicum ; Bacillus subtilis, B. amyloliquefaciens, Pseudomonas fluorescens, Streptomyces griseoviridis, S. lividans , S. roseoflavus, ... They are not currently used in the field in France.


* 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.