Botrytis gray mold

Authors: Chen, Weidong; ZHU, ZENGDONG - Chinese Academy Of Agricultural Sciences; Porter, Lyndon

Submitted to: American Phytopathological Society Press
Publication Type: Book / Chapter
Publication Acceptance Date: 4/20/2020
Publication Date: N/A
Citation: N/A

Interpretive Summary: Botrytis gray mold affects all above ground parts of pea plants and is caused by the necrotrophic fungus Botrytis cinerea. Botrytis cinerea has a worldwide distribution with a wide host range consisting of more than 200 plant species. Because B. cinerea has a broad host range, can grow on dead plant tissue, and produces large quantities of spores that can be carried by wind, the pathogen is almost always present in all pea-growing conditions. This chapter describes the pathogen responsible for gray mold, disease symptoms, and approaches for managing the disease. Disease symptoms are illustrated with photos.

Technical Abstract: Botrytis gray mold affects all above ground parts of pea plants including stems, leaves, flowers, pods, and seeds under humid conditions. The disease is caused by the necrotrophic fungus Botrytis cinerea. Symptoms of Botrytis gray mold usually appear on succulent tissues and are characterized by gray-colored lesions producing asexual spores (conidia). Botrytis cinerea may also form small black structures called sclerotia on infected tissue. Botrytis cinerea has a worldwide distribution with a wide host range consisting of more than 200 plant species including many cultivated crops and weeds. Botrytis cinerea can survive between pea cropping seasons on infected plant debris as mycelium, conidia, and sometimes as sclerotia, or on other host plants. The pathogen can develop massive grayish-colored conidia that give the appearance of gray mold hence the disease name. Temperature ranges from 16 to 21°C, and relative humidity above 95% are most favorable for gray mold development. Because B. cinerea has a broad host range and can grow on dead plant tissue and produce large quantities of conidia that can be carried by wind, the pathogen is almost always present in all pea-growing conditions. The most important management practice in controlling Botrytis gray mold is reducing relative humidity by delaying canopy closure with increased row spacing or within-row plant spacing, which promotes air circulation.