Pest risk analysis of Diaporthe cucurbitae and Stagonosporopsis citrulli for Cucurbitaceae seeds

In the course of the work, for the first time, a pest risk analysis (PRA) was carried out for the pathogenic fungi Diaporthe cucurbitae and Stagonosporopsis citrulli for regulated products – Cucurbitaceae seeds. The agent of black rot Diaporthe cucurbitae can cause death of seedlings in case of early infection. On host plants fruits, the phytopathogen causes symptoms in the form of brown, soft, sunken lesions of irregular shape, leading to a significant deterioration in commercial qualities. The main pathway of the fungus is the Cucurbitaceae seed material. The causative agent of mycosis is able to be transmitted mechanically between plants during agricultural activities, with the help of wind and drop-liquid moisture, and also persist in plant debris, starting a new cycle of disease development in the next growing season. Stagonosporopsis citrulli belongs to the group of viscous rot pathogens, consisting of three morphologically similar, but genetically different species: Stagonosporopsis citrulli, Stagonosporopsis cucurbita­ cearum and Stagonosporopsis caricae. Infection can occur on leaves, stems and fruits. The pathogen can be transmitted through seedlings from infected seeds. Due to the widespread cultivation of host plants on the territory of the Russian Federation and the possible negative consequences of the introduction and spread of the above-stated pests, it was decided to conduct a PRA as part of a study of the phytosanitary safety of Cucurbitaceae seeds. The PRA results showed that Diaport­ he cucurbitae and Stagonosporopsis citrulli can harm the production of Cucurbitaceae in Russia, but the potential damage of these phytopathogens is low, so they are not recommended for inclusion in the list of regulated pests.

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