Strawberry leaf scorch
The disease overwinters in plant debris and infects strawberry plants during the spring season when it is wet. The disease mainly infects strawberry leaves at any stage of the its life cycle, but may infect all parts of the strawberry plant, including the petioles, fruits, and stems. The disease is characterized by numerous small, purplish to brownish lesions (from 1/16 to 3/16 of an inch in diameter) with undefined borders on the upper surface of the leaf. These symptoms are different from strawberry leaf spot which has brown lesions with defined borders and a lighter center. As the leaf scorch progresses over time, the leaves turn brown and dry up, resembling a burnt or “scorched” appearance as indicated by its disease name. It is common for the petioles of the leaves to have purple, sunken lesions that resemble streaks. If these streaks are severe enough, they may lead to the bowing of the petiole which in turn kills the leaf. Strawberry leaf scorch infects all parts of the flower, leading to unattractive blemishes on the fruit (strawberries).