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Press, 12 April 1979, Page 14

It is not at all uncommon to see copious exudation of gum on stonefruit trees. This feature is known as gummosis. Gummosis may be caused by one of several diseases, on a combination of two or more. Commonly associated with this affliction is die-back, coral spot, brown rot and peach scab.

It can arise as a result of injury sustained through abrasions such as rubbing limbs, branch breakage or careless pruning — particularly pruning at the wrong time of the year, as often happens with cherry trees. What happens is that the woody tissues break down into gum. The wood coil cavities swell, pockets are formed which fill with gum and when these rupture, the gum oozes out.

Where such occurrence is slight there is little effect on the tree’s wellbeing. In severe cases death of the branch is likely, or possibly the

whole tree can suffer and may even die. A noticeable feature is the smaller and fewer leaves present and the small amount of growth. The incidence of gum-

mosis can be greatly reduced by correct and timely pruning and spraying, together with the sealing of cut surfaces and avoidance of damage to the root system.