pecies can get too much of a good thing. When foliage or fruit is exposed to excessive sunlight, plant tissue can get a bit of sunburn, generally referred to as sunscald. Sunscald is often exacerbated by high temperature and drought.
Sunscald symptoms will appear as yellow or white lesions on foliage and/or fruits. The lesions eventually may turn brown and/or shrivel. Foliage that is commonly affected includes impatiens, hosta, rhododendron, garden beans, peas, peppers and tomatoes.
Fruits that are frequently victim of sunscald include tomatoes, peppers, strawberries, raspberries, blackberries, grapes and apples. In many cases disease and insect damage to the foliage, or excessive pruning, results in the fruits becoming over exposed to sunlight. Once the fruit is damaged, other soft rots may invade the fruit to cause further damage.
Encouraging healthy foliage by proper positioning in the garden, appropriate fertilization, pruning and pest control can help prevent sunscald on garden plants. Using tents or screens to provide light shade in late afternoon may also help. Moving susceptible perennials and shrubs to more-protected locations, particularly away from the afternoon sun, may be warranted.
Young trees, particularly thin-barked species such as apples, crabapples, cherries, maple, tuliptree, ash and poplar, may also experience sunscald. Prevent sunscald to young trees by wrapping the trunks with paper or plastic tree wrap products that are specifically designed for this purpose. These wraps should be applied in late fall or early winter and removed by early spring to avoid overheating the young bark during the growing season. After two or three growing seasons, the bark should no longer need wrapping.