Sun Scald On Fruit...

Press, Volume CII, Issue 30057, 15 February 1963, Page 6

Sun Scald On Fruit...

Hot, sunny weather is everyone’s ideal for summer. It provides ample opportunity for outdoor activity, and it hastens maturity of fruits and vegetables. However, it can cause trouble.

Just as we are liable to , sunburn from excessive or sudden exposure, so, too, is it with plants. The trouble we will consider here is sun scald—a common enough physiological disorder in various types of fruit such as apples and tomatoes.

Sun scald affects those parts of the fruit directly exposed to strong sunlight and the damage is caused by a combination of light and heat In the accompanying illustration is shown a heavily laden branch of an apple tree which has been bent over by excessive weight of fruit. In consequence the fruit has become suddenly exposed to the sunlight without any gradual hardening process. Circular, brown,- flattened areas, sometimes surrounded by a bright reddish halo, become apparent Areas that are only slightly affected show

circular pale brown areas, or areas with a deeper flush of colour depending on variety. Some varieties are more susceptible than others. Stunner is one of these.

The condition, glassy core and crinkle, has also been attributed to high temperatures.

In tomatoes, while the rest of the fruit becomes red when it ripens, the affected part remains yellow. In severe attacks, the affected part becomes white. This later shrinks, and becomes greyish with a dry papery surface. Prevention Jn the case of apples, when branches bend over due to weight of fruit, props should be provided to give support to the heavily laden branch. In cases where foliage is lacking, shading can be introduced by the use of straw or newspaper. Where sun scald affects tomatoes under glass, shading in the form of a lime wash can be applied to the glass. Outdoor crops can be protected by using a thin layer of straw or hay to lightly cover the trusses of fruit.