52 Provincial Board of Horticulture. 1897 



In Oregon, the disease exists largely, and it is there concluded— "That the causes of 

 guinmosis ar°e not always the same, or apparently not. It is probably a disease of the physio- 

 fogical nature, and affects nearly if not all of the stone fruits. It may appear in either of two 

 forms, local or constitutional. Locally in the form of gum pockets on trunk or branch in 

 isolated situations. The constitutional form may also show gum-pockets, but these will be 

 found upon examination of cross-sections of the wood to be connected with each other by a 

 series of gum-filled cells in the wood, which may be seen with the eye as dark brown lines or 

 cells. Either local or constitutional gummosis is most likely to affect trees which have been 

 quite dry at one time and wet at another. 



" Mr. Newton B. Pierce suggests the following : — Cut out as much of the diseased 

 Treatment bark as possible, and spray the trees with Bordeaux mixture."— Report of 

 Recommended, the Oregon State Board of Horticulture. 



I have received very favourable reports concerning the treatment of gummosis, by a free 

 use of wood ashes applied to the soil on which the trees stand, especially when combined with 

 mulching to retain moisture, and although this may appear a very indirect way of treating the 

 disease, it is one I strongly recommend. If wood ashes are not available, air-slacked lime and 

 muriate of potash can be used instead, in the same way. 



Powdery mildew (Podosphcera oxyacanthce) is reported from Victoria, Saanich, New West- 

 minster, Ladner's Landing and Vernon. 



Powdery mildew appears usually about mid-summer, as small round whitish blotches, 



which soon enlarge and run together on the leaves and young shoots of most varieties of fruit- 



trees. It spreads by means of spores, immense numbers of which are pro- 



^ ^'"'' ' ■ duced and disseminated ; wherever there is light and sufiicient moisture 



present, they germinate and start the disease anew. It is usually more abundant on young 



trees than old ones, and is especially destructive to nursery stock. 



The powdery appearance is caused by the presence of large numbers of minute white 

 spores, known as conidia or summer spores. The disease is carried over winter on the leaves, 

 etc., in spores contained in small black cases, called perithecia, which are just visible to the 

 naked eye. The mycelium or vegetative portion of the fungus is external. 



Spray with diluted Bordeaux mixture or the carbonate of copper solution, making the 

 _ first application when the leaves are about half grown, and repeat three or 



four times at intervals of ten days. 



This well known disease (Sphwroiheca moTS-uvm) of gooseberries of English varieties, is 

 common all through the lower Province, and the past season has been very injurious in the 

 Okanagan District. It is noted that in Nanaimo there is little injury from 

 S^ifS^.l'"'"^ t'^i^ disease, and as a consequence the choice varieties of gooseberries are 

 largely grown there, ihe reason of this comparative exemption has not 

 been satisfactorily explained. This fungus usually appears in spring upon the leaves and buds, 

 first showing as a sparse, cobwebby covering, which later appears white and powdery, from the 

 production of summer spores. The young berries are also attacked, sometimes being dwarfed 

 or mis-shaped. As the summer progresses, infested leaves and fruit become browned, and 

 covered with a thick growth of the fungus mycelium. The summer spores are very light, and 

 blow about vyith the wind; when one falls upon a damp gooseberry leaf or fruit, it germinates 

 by sending out a slender tube, from which the mildew spreads. As these summer spores are 

 unable to survive the winter, the fungus produces what are called winter spores, consisting of 

 small round cases, from which project about a dozen short, delicate appendages. These are 

 the outer spore cases, and contain flattened oval bodies called the inner spore cases, within 

 which are spores which germinate in the spring. Gooseberry mildew is often very difficult to 

 control, chiefly because preventive measures are begun too late. 



Spraying with Bordeaux mixture should commence very early, just as soon as the leaf 



buds burst, and be repeated at intervals of a week or ten days for three or four applications; if 



further treatment is required after the fruit is well formed, use a spray made 



Remedies. with sulphide of potassium (liver of sulphur), at the rate of | oz. to 1 gallon 



of water. A winter spraying of gooseberry bushes before growth starts, with 



