Agent pathogène

The genus Monilinia encompasses several fungal species that cause brown rot in various fruit crops such as Monilinia coryli, Monilinia laxaet Monilinia fructigena. These fungi share common characteristics, including the apothecia production from pseudosclerotia, which form in mummified fruit or other plant debris.

The disease cycle of Monilinia involves three stages:

1. blossom blight and twig cankers in early spring,
2. active brown rot in late spring and summer, and
3. the presence of mummified fruit either remaining on the tree or in the soil.

Overwintering occurs in infected fruits or twig cankers, which serve as reservoirs for the pathogen. In the spring, Monilia species release ascospores and conidia, the primary inoculum, which are dispersed by wind or rain.

Once the spores land on susceptible plant tissues such as blossoms and fruit spurs, infection can spread rapidly, particularly under moist conditions. Fruit rot can develop quickly, and the infection may remain latent until the fruit ripens.

Symptômes

The infection typically begins during the bloom stage, causing blossom blight. Infected flowers and tissues exhibit water-soaked lesions and turn dark brown to black. As the infection progresses, the affected flowers may wilt and die.

As the pathogen continues its cycle, it causes nut rot. Infected hazelnuts develop brown to black lesions on their surface, often accompanied by visible masses of mycelium and spore. In some cases, necrosis can be observed on unripe nuts. The pathogen also affects the pericarp (husk), where light brown to chestnut-colored spots appear. These spots gradually expand and can eventually cover the entire fruit. Early infections may cause premature fruit fall. Additional symptoms include stem cankers, discoloration, and open wound development.

FieldClimate Modèle

General Monilinia Risk Model

Capteurs nécessaires :

• Températures de l'air
• Humidité des feuilles

The model calculates the risk of Monilinia species. When the graph reaches 100%, optimal conditions for a Monilinia infection have been set in orchards and curative plant protection measurements should be considered.

La littérature :

Di Francesco, A., & Mari, M. (2018). Monilinia species of fruit decay: a comparison between biological and epidemiological data. Italian Journal of Mycology, 47, 13-23.

Martini, C., & Mari, M. (2014). Monilinia fructicola, Monilinia laxa (Monilinia rot, brown rot). In Postharvest decay (pp. 233-265). Academic Press.

Machowicz-Stefaniak, Z., & Zalewska, E. (2000). Pathogenicity of Monilia spp. to hazel (Corylus). Acta Mycologica, 35(2), 269-274. https://pinova.hr/en/bolesti-lijeske/