Biology, epidemiology

The biology of Monographella cucumerinum is not well understood; however, it seems to keep easily for several years in many soils, especially on plant debris. This fungus has been isolated from many soils around the world and from the roots of a wide variety of hosts. In addition to Cucurbitaceae, it is particularly pathogenic on basil, lupine, sunflower, peanut, sugar beet, bellflower, etc.

In France, we have observed it fairly systematically and isolated it on the roots of tomatoes grown in soil, but above all in soilless. It is in this latter cultural context that it finds particularly favorable conditions for its development. It is isolated on the roots with very high frequencies at certain times of the year, higher than those obtained for Fusarium oxysporum . Its parasitic status in soilless crops is still poorly defined. It was also described in Egypt, in 1981, as responsible for root rots, yellowing and leaf wilting followed by mortalities of tomato seedlings.

It is disseminated through wind and water.

It appreciates rainy and humid climates, and cool temperatures. Note that the thermal optimum for the germination of its conidia is of the order of 25 ° C. It forms numerous conidia (figure 1) on the altered tissues present on the various organs; these are dispersed by the wind over long distances but also by splashing water. It also produces perithecia (figure 2) materializing its sexual reproduction.