Monosporascus cannonballus  Pollack & Uecker, (1974)

- Classification: Fungi, Basidiomycota, Lichinomycetes, Xylariomycetidae, Xylariales, Incertae_sedis_.
- English names: Monosporascus root rot, vine decline

A second species of Monosporascus , Monosporascus eutypoides (Petr.) Arx, (1976), is more occasionally involved in root dieback in Cucurbitaceae.


Monosporascus cannonballus soil is a fungus * which is responsible for severe root dieback in several Cucurbitaceae. It mainly affects melon and watermelon, both in greenhouse and in fields. It is at the origin of significant reductions in yields which can negate the harvest in certain extreme cases.

This emerging disease is characterized by rapid and uniform wilting of whole crops usually two weeks before harvest. It has been identified in many production regions of the world, preferably in arid and semi-arid areas. It has been reported in particular in the United States (Arizona, California, Texas), and in other American countries (Mexico, Guatemala, Honduras, Brazil), in Asia (Japan, Korea, Taiwan ), India, Libya, Israel, Tunisia and in some European countries bordering France (Italy, Spain).

The proximity of production areas already affected by this fungus and located in neighboring countries, but also global warming should prompt us to be vigilant. In 2012, we were able to associate a Monosporascus sp. with the dieback of melon plants in a culture under shelter located in the south of France (region of Montpellier), this in complex with Phomopsis sclerorioides . In 2015, M. cannonballus was found again in the south-east (Avignon region) on zucchini root systems exhibiting rather atypical symptoms.

 
* It should be noted that several fungi, alone or in complexes (this varying according to the production zones and the plots), have been associated in the world (Japan, Israel, Spain, Italy, USA ) with wilting and collapse of melon plants (vine decline, vine collapse), accompanied by lesions and root rots. Among the most common are: Acremonium cucurbitacearum (Syn. Nodulisporium melonis , now called Plectosphaerella melonis ), Macrophomina phaseolina , Monosporascus cannonballus , Pyrenochaeta lycopersici , Pythium spp., Rhizoctonia solani , Rhizopycnis ...