SUNSCALD IN VEGETABLES
Sunscald occurs on the sides exposed to direct sunlight and leads to sudden raise of vegetables internal temperature which causes tissue damage. Sunscald develops when high temperatures and high light intensities cause rapid evaporation of moisture from flower petal. However if it is suddenly exposed to bright sun for even a relatively short period, it will burn and causes damage to the fruit or vegetable.
Sunscald also occurs after harvesting especially on dark fruited vegetables such as,egg plant, watermelon, summersquash.
Sunscald primarily effect the vegetables, although the foliage may get white streaks and dry edges. The fruit will crack and split wherever the scald occur. White scars of tougher tissues are formed at the burned sites.
It first appears as wrinkled area that can be soft and lighter in colour than surrounding tissue. This area later turns white and paper like structures. Fruits have yellowish or whitish patches on side exposed to sunlight. These patches turn leathery and dry out. The many becomes infected with various types of mold as secondary infections in the wounded tissue. Fruits protected by shade from leaf cover of shading material are unaffeacted However, if it is suddenly exposed to bright sun for even a relatively short period it will burn.
In immature vegetables they appear light green in colour. This knowledge will helps growers take steps to minimize damage.
List of major vegetables showing their symptoms of sunscald.......
EFFECTS IN LEAFY VEGETABLES:
I know it may be seen an article about sunscard or sunburn on leaves with week of rain we just had, but leaves came in over the last week as the rain started and the damage had been done days before this. It is also possible that there will be a greater chance for sunscald in the coming days as growers try to get their transplants out. An area on the leaf turning papery white.
Many of these plants were set in the field after coming straight out of the green house or off the trailer. Before the rains we had a few days of very hot temperatures and intense sunlight. The problem with taking plants straight from this type of environment to the fields is that the plants at times are not ready for the extrra UV light they are going to receive. The leaf tissue rapidly becomes dessicated with the extra light or heat exposure, causing light tan to white discolouration on the leaves and stems of sensitive plants.
EFFECTS IN TOMATO:
Sunscald of tomato occurs when green or ripening fruits are exposed to direct prolinged sunlight, especially during, sunny hot weather. Large light-coloured blistered areas develop on the sides of fruit facing the sun.
It is most prevalent on plants that have lost foliage due to insect feeding or disease. For example, early blight disease of tomatoes can cause large number of leaves to die, exposing fruits to intense sunlight. The conditions renders fruits inedible.
EFFECTS IN PEPPER:
Sunscald on pepper primarily affects the fruit, along the foliage may get white streaks and dry edges. The fruit will crack and split where the scald occurs. White scars of tougher tissue are formed at the burned sites. In immature peppers, the affected areas are light green.
The areas can also appear dry and sunken, however the cracking can allow bacteria or fungi into the fruit. In these cases the fruit will soften and the burnt areas will become rotten. Remove any fruit that has been affected before it gets soft and usually it is fine to use.
EFFECTS IN PUMPKIN AND WINTER SQUASH:
Sunscald of pumpkin and winter squash can occur when exposed to sunlight as a result of loss of leaves. Sunscald injury starts on the top of fruit, often the part facing the sun during the morning. Initially the rid may appear water soaked and will slough off when rubbed.