• During cultivation

It should be noted above all that the struggle during cultivation against Athalia rolfsii soil , a fungus, is practically impossible, no means being sufficiently effective to stem the evolution of this parasitic fungus.

We can still offer to manage the irrigation as best as possible (optimal quantity, localized supply, etc.).

The healthy plant debris or sick , may harbor or encourage the development and conservation of the fungus in the soil should preferably be eliminated during and at the end of the culture and the weeds potential hosts.

• Next crop

Its wide range of potential hosts and the limited number of non-host plants make crop rotations seldom effective against this fungus. In new plots or in plots little or not affected, crop rotations will be recommended with corn or other cereals described as not very receptive to this fungus. The sensitivity of corn and wheat seems quite controversial in the literature. Although onion is susceptible, winter crops of this vegetable at a time not conducive to the development of A. rolfsii would reduce the viability of sclerotia. The latter would be more sensitive to soil antagonists under the effects of exudates excreted by this Allium.

Admittedly, the polyphagia of this fungus and its potential to be maintained on practically all plant debris often considerably reduce the efficiency of crop rotations in soils where the fungus is already well established.

The heavy, wet soils are drained . Deep plowing will be done so that plant debris and sclerotia can be destroyed more quickly by burying them deep.

In heavily infested soils, it may be considered before planting to eliminate or minimize the inoculum present by carrying out disinfection . For this, several solutions can be chosen:
- the use of a fumigant (metam-sodium, dazomet, etc.), steam or other products (formalin, PCNB);
- solarization in sunny regions. It consists of covering the floor to be disinfected, which will have been carefully worked and moistened beforehand, with a polyethylene film 25 to 50 µm thick. The latter is kept in place for at least a month at a very sunny time of the year. This economical and efficient method should make it possible to get rid of this colonizing fungus from the surface area of ​​the soil. In fact, it seems that it is only removed in the first few inches of the ground. This therefore implies planting immediately after solarization, before this stratum is recolonized. This situation would be such as to limit the use of this method in the climate of France. Note that solarization has been successfully combined with the contribution of antagonistic fungi to the soil, such as Trichoderma harzianum .

A. rolfsii does not appreciate alkaline pH, liming the soil is frequently recommended. For the same reason, certain fertilizations rich in calcium would reduce the incidence of this fungus by raising the pH, especially if the rate of inoculum in the soil is low. It would be the same for certain soluble nitrogenous fertilizers brought to the surface of the soil (urea, ammoniacal salts). To maintain the partial effectiveness of the latter, we will split the inputs and avoid leaching the soil.

The quality of the plants is often a guarantee of those of the future culture and harvest. For this reason, the plants must be healthy and produced in ways that exclude excessive vegetation and etiolation, the latter defect often requiring too deep planting. The equipment used for the production of the plants will be well cleaned and disinfected, for example with a 10% bleach solution for several minutes. Rinse well as this product is corrosive. When planting, the clods will be buried as little as possible, and in any case the collar should not be covered with soil. The presence of dead leaves or weeds near the base of the plants should be avoided, as these can serve as the primary food source for the fungus. Weeds will be destroyed.

Some authors report that plastic mulching would reduce the incidence of the disease on certain plants by creating a screen between colonized plant debris, present in the soil, and the lower parts of the plants. In any case, such mulching helps to increase the temperature and maintain soil moisture, and reduces weeds.

Note that fungicides have been tested to control A. rolfsii . These products have been used alone or in combination with microbial antagonists, depending on different supply strategies: to the soil before or at the time of planting, by imbibition of the crown, etc. These same delivery methods have been used for antagonist fungi , the latter sometimes being associated with organic matter. Indeed, several of them revealed, under controlled conditions, a certain antagonism vis-à-vis A. rolfsii . Among them are Trichoderma viride, Trichoderma harzianum and Gliocladium virens . Their effectiveness turned out to be more uncertain during field experiments.

To our knowledge, there is no variety tomato resistant to A. rolfsii .


* 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.