Why Are My Strawberries Rotting on the Vine?

Botrytis Cinerea

• This strawberry fungus, commonly referred to as Botrytis mold or gray mold, occurs over the winter and resides in the leaves or fruit of a strawberry plant. Botrytis mold is not detectable at this point since the spores of the fungus lay dormant. When spring begins, the spores begin their life cycle. The warm and moist conditions of the weather allow the fungus to propagate, invading every part of the plant and slowly killing it. This is a serious condition, because it makes the plants inedible.

Symptoms of Gray Mold

• Since the strawberry fungus lies dormant over the first couple of months, it is difficult to detect at an early stage. The earliest symptoms of the fungus occur on the leaves, where the leaves turn brown or yellow and start to wither. At later stages, the strawberry fruits become infected and begin growing a dark brown color. Eventually, the physical mold appears containing more spores. These spores release and spread into the environment, continuing the life cycle of the fungus.

How do Strawberries Become Infected

• All strawberries are susceptible to this fungus, but damaged fruits and plants are particularly prone to becoming infected with the fungus. Oftentimes, a spore that releases by wind or water attaches to a strawberry plant. Strawberry plants within close proximity to each other are especially susceptible to gray mold. Another contributing factor to a gray mold infestation is if the strawberry plants are not thoroughly drained.

Preventing Gray Mold on Strawberries

• Preventing gray mold from occurring on strawberries is much simpler than trying to cure them. Keeping the soil of strawberry beds loose and well drained is an important first step. This ensures that water and any spore deposits drain away from the plants. Applying water early in the day also ensures that there is no excessive moisture for the fungus to propagate. The water evaporates earlier in the day, and since fungus needs water to thrive, it will stand less of a chance. Plants should also be spaced apart, at least enough to prevent leaves from touching and crowding. If a plant does become infected, it should be removed and the remaining plants closely inspected.