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Sour sap continued to take a steady toll of trees in Auckland and Nelson districts, where large areas of orchard are established on clay soils with poor natural drainage. Following trials by the Department of Scientific and Industrial Research, a more resistant rootstock, Mailing No. XII, is coming into use on this class of soil, but supplies are limited as yet. The primary cause of sour sap is an excess of soil water. Methods of draining these clays therefore require investigation, as no known rootstock can survive in waterlogged soils. Gnarling of Gravenstein trees remains an unsolved problem and one that is seriously affecting the health and productivity of orchards planted with this important variety. Trials conducted by the Department of Scientific and Industrial Research and observation of the disease in orchards by officers of the Department of Agriculture have shown that trees propagated on Gravenstein roots, though not immune, are much superior in vigour to trees on Northern Spy stock. Own-rooted trees are therefore being recommended for all future plantings of this variety. In Nelson a disease causing sudden collapse and death of healthy, mature Cox's Orange Pippin trees has shown greater incidence this year. Delicious trees are also susceptible, though decline is less rapid in this variety. No causal organism has been isolated and affected trees usually have healthy roots. Trees thirty-five years of age or older are the most susceptible. Henderson spot or thumb mark, a suspected virus disease affecting fruit of the Granny Smith apple, has spread rapidly throughout the Auckland district during the past two years. The disease first came under notice in 1938. Almost all orchards contain infected trees, the number of diseased fruits on individual trees varying from a few to almost the whole crop. The disease is being observed closely by officers of the Department. In Nelson and Marlborough several rabbit and hare-repellant materials for application to fruit trees have proved effective in tests made by the Department. In similar trials at Motueka the materials protected the bark of trees from injury, but new growth was attacked in the spring as it appeared. The " long lateral" system of pruning apple-trees has given good results in Marlborough trials and is being increasingly adopted by local growers. Stone-fruits (Peach, Apricot, Nectarine, Plum, and Cherry) Several factors have contributed to the continued expansion of stone-fruit growing. One has been the high prices which have been general during the past few years and greater in proportion than the controlled increase received by pip-fruit growers. Allied with this is the fact that peaches in particular begin to produce much earlier than apples and pears. Another factor has been the increased supply of trees, both locally grown and imported from Australia, which has enabled growers to replace uneconomic trees or fill gaps in orchards as well as to extend their areas. The most noticeable increases have been in apricots (about 110 acres) and peaches (90 acres). Practically all these apricots have been planted in the Central Otago area, but new peach plantings have been made fairly widely, the most important being in Central Otago (30 acres), Auckland (20 acres), Hawke's Bay (19 acres), and Nelson (14 acres). Smaller increases have taken place in the numbers of plum-trees, mainly Japanese varieties ; Central Otago shows the greatest increase (about 25 acres), followed by Hawke's Bay (7 acres), and Auckland and Nelson (5 acres each). Areas in nectarines and cherries have remained fairly steady, though Central Otago has recorded an increase of 10 acres of nectarines and 5 acres of cherries. A number of new orchards, either wholly or partly of stone-fruit trees, have been established, particularly by ex-servicemen, and further plantings are projected. On the Motukawa settlement, near Blenheim, which will be planted shortly, fourteen ex-servicemen will each have approximately 5 acres of stone-fruit.

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