Deep cankers develop on the branches, thus exposing the inner tissues. Dieback occurs if the stem is girdled. The fungus can enter through wounds caused by other diseases and pests, which should be controlled. All dying branches and diseased tissues should be cut out and burned and the wounds painted with a canker paint. Spray severely diseased apples with Bordeaux mixture just before leaf fall, at 50 per cent leaf fall and at bud burst when most spore release occurs. Many small cankers are produced by willow anthracnose but remove cankered shoots on small, slightly affected trees. A copper fungicide or thiophanate-methyl applied at bud burst, repeating two or three times at fortnightly intervals, may help to control it. Raspberries are affected by several shoot diseases including cane spot and more importantly spur blight and cane blight. Spur blight leads to death of buds or dieback of shoots whereas cane blight kills complete canes causing them to become brittle so they are easily snapped off. Remove any diseased canes preferably to below soil level. Spray with a copper fungicide, benomyl, dichlofluanid or thiophanate-methyl as new canes develop, repeating at fortnightly intervals until flowering ceases. OTHER FRUIT DISEASES Brown rot causes a rapid decay of top fruits on trees and in store. The fungus produces cushions of white spores on the brown rotting fruits before they dry up. It then overwinters on the mummified fruits on the tree or ground and also on small shoot cankers. It can only be kept in check by destroying all rotten or withered fruits and by cutting out dead shoots. WOUND PARASITES A typical example of a wound parasite is the silver leaf fungus which causes silvering of the foliage on an infected branch, followed by progressive dieback of the tree or shrub. Many types of woody plants are susceptible to infection and not only plums; for example, rhododendrons and roses are other plants affected. Another very common and troublesome wound parasite is the coral spot fungus. Once it has gained an entrance it causes dieback of branches or occasionally the complete death of a plant. The dead shoots bear numerous coral-red pustules of spores. Plants most susceptible to infection are acers, elaeagnus, figs and red currants.Affected branches should be cut out to a point several inches below the apparently diseased tissues, which, in the case of silver leaf, show a stain in the wood, and all wounds should be painted with a protective paint. Destroy all woody debris on which the fungi can live as saprophytes. SOIL-BORNE DISEASES Club root, which produces swollen distorted roots on brassicas, wallflowers, etc., occurs where susceptible plants are grown year after year in acid soils, particularly those which are poorly drained. Liming, together with the use of 4 per cent calomel dust, or preferably benomyl or thiophanate-methyl may help to prevent it but it is impossible to check it completely unless the soil is sterilized with dazomet, and crops are rotated.