MILDEWS

Sun (Auckland), Volume II, Issue 400, 14 July 1928, Page 26

MILDEWS

HOW THEY ATTACK in all the diseases so far considered, the fungi which cause them penetrate into the tissues of the host and are not readily detected until a good deal of damage has been done, in addition to which the positions they occupy make it very difficult to get at them when once they are established. There is another large group affecting all kinds of garden plants, which form a felted covering or network of fine threads on the outer surface of the subject attacked. These are known as the mildews. As an example of this type of disease the gooseberry mildew may be taken. This makes its appearance on gooseberry and currant bushes as a fine, web-like or powdery film on the young leaves. As the disease develops, large brownish patches are noticed, which may extend to the stems and growing-tips of the shoots. The fruit suffers by becoming dry and cracked on the outside, decay eventually setting in. Resting spores fall to the ground from the infected bushes late in the season and lie dormant till the following summer, when they ger ruinate and cause a reappearance of the disease. Onion mildew is another common ill

which sometimes works considerable havoc,in the kitchen garden. The symptoms are the withering of the tips of the leaves .and the abnormal growth of the top portion of the bulbs. As the leaves are destroyed, the nourishment of the whole plant is interfered with, so that the bulbs formed are small and “thin.” Cabbage mildew causes the leaves of cruciferous plants to turn yellow and fall. The spores are released in the ground and remain inactive until conditions which favour their growth and development arise.