774 Insect and Fungus Pests during Winter. [Nov., 



Many leaf spots and other leaf diseases which cause premature 

 loss of foliage are carried through the winter by the fallen 

 leaves. Such leaves should be raked up and burnt. 



The pruning of trees and bushes is usually undertaken for tho. 

 purpose of shaping the growth and allowing light and air to 

 penetrate the foliage, but where the operation is done properly 

 the spread of disease is effectively checked. Wounds, however, 

 should be treated antiseptically to prevent further disease. It 

 is now known that reinfection in several fruit and leaf disease's, 

 such as Brown Kot of plums and apples and Apple and Pear 

 Scab, takes place from infected twigs and spurs, as well as from 

 " mummied " fruit, so that these should be carefully cut away. 

 Dead w^ood should be removed from plum trees, as Silver 

 Leaf is often caused by such remaining on the tree. 

 Stereum pupureum, which causes the disease, only produces its 

 spores after the wood has been killed. It is for this reason, 

 and also because dead wood on a tree is useless and a danger, 

 that the Ministry's Order compelling the removal of dead wood 

 from plum trees before the 1st xlpril of each year was made. 

 It is important that the dead and diseased wood removed should 

 be burnt, as many of the destructive fungi continue to develop 

 after the wood has been removed from the tree. Before the 

 Silver Leaf Order came into operation piles of wood, and even 

 posts and fences, could commonly be se.en, on which the causal 

 fungus was breeding and reinfecting hitherto clean trees. 



Spraying. — Spraying is an effective means of controlling the 

 ravages of pests. A normal winter spray usually has as its 

 basis caustic soda. A caustic soda spray will remove lichen, 

 moss and other parasites on the bark of trees which serve as a 

 place of refuge for insect pests. A solution of copper sulphate 

 is sometimes used to kill fungus spores. Lime-sulphur 

 solution has the merit of being a cleansing agent as well as a 

 fungicide, and is much in favour at the present time. This 

 spray can also, if necessary, be used every year without injuring^ 

 the bark, whereas the use annually of a wash made of caustb 

 soda has an injurious effect on the trees. 



Spraying should be done after pruning, although not 

 necessarily immediately afterwards. The best results are 

 obtained when the operation is deferred as late as possible. It 

 is commonly stated that the solution should be apphed " before 

 the buds swell," but in practice it is better to wait until the buds 

 have swollen, or even after they havQ commenced to open,^ 



