Botrytis blight, also known as gray mold, is a common fungal disease that affects blueberry plants worldwide. It is caused by Botrytis cinerea, a fungus notorious for infecting a wide range of crops, including strawberries, grapes, and tomatoes. The disease is most active in cool, wet, and humid conditions—typically during periods of prolonged rainfall or poor air circulation in dense canopies. When conditions are favorable, Botrytis can cause severe damage to blossoms, stems, and fruit, leading to significant economic losses for blueberry growers.
The disease usually begins during the flowering stage. As blueberry blossoms open, their corollas (petal tubes) age and become susceptible to infection. Ideally, the corolla should drop naturally after pollination, but if weather delays this process or if frost damages new growth, wounds may form that invite fungal invasion. Once infected, blossoms turn brown, shrivel, and often remain attached to the plant. Under humid conditions, they become covered with a characteristic gray, fuzzy mold.
Botrytis cinerea is an opportunistic pathogen that thrives on weakened or dying plant tissues. It survives in the environment as a saprophyte, feeding on dead leaves, pruned canes, or other plant debris. The fungus produces abundant spores that can easily spread through wind, rain, or mechanical contact during harvesting. Because spores are often present throughout the growing season, complete eradication is nearly impossible.
Symptoms of Botrytis blight vary depending on the infected plant part. Leaves may develop yellow spots that later turn brown and gray, while infected twigs can die back from flower blight. On ripening or stored berries, the disease manifests as soft, gray, moldy rot that causes fruit to shrivel and decay. Although postharvest fruit rot is common in regions where berries are stored for long periods, it is less of a concern in areas like Florida, where fruit moves rapidly from harvest to market.
Effective management of Botrytis blight involves maintaining good air circulation, removing dead plant material, and avoiding overhead irrigation. While sanitation alone cannot eliminate the disease, it remains an essential component of integrated fungal control strategies to protect blueberry yields and quality.Botrytis Blight: A Fungal Threat to Blueberry Crops
