The principal enemies of the loquat in California are pear-blight (Bacillus amylovorus Trev.) and loquat-scab (Fusi-cladium dendriticum var. eriobotryce Scalia). Condit says of the former: "The pear blight is a serious enemy of the loquat at times, blossom blight often being especially abundant on trees during the spring months. Infected twigs should be cut off well back of the diseased area and burned, care being taken to sterilize the pruning shears in alcohol or formalin after each cut so as to reduce the danger of further infection. Occasionally entire trees are killed by the blight, which gradually extends downward from the branches into the trunk, although in most cases the disease does not seem to progress much beyond the branches. Some varieties are more susceptible than others. For example, the Advance is quite resistant and the trees of the Victor, which were very susceptible when young, have in later years become more or less immune; the Champagne showed considerable blossom blight in the spring of 1914, but to no greater extent than young trees of other varieties. The trees seem to gain resistance as they grow older."
In regard to the scab he says: "This is reported to be a serious disease of the loquat in Australia. The fruit is attacked when half grown by brownish black spots, which soon extend, stop its further development, and disfigure its appearance. The fleshy part of the fruit becomes desiccated and the skin seems to cling to the stones. A large proportion of the crop may in a short space of time be rendered absolutely unsalable. It is also well known in Italy upon the leaves. In California the scab is quite common both on nursery and bearing trees, attacking both leaves and fruit. . . . Spraying with Bordeaux mixture after the blossoms have fallen and the fruit is setting should prove an effective remedy."
In Florida the flowers are sometimes blighted by the an-thracnose fungus (Colletotricham gloeosporioides Penz.). Bordeaux mixture, prepared according to a 3-3-50 formula, should be used to combat this disease.
E. O. Essig 1 mentions four insects which occasionally attack the loquat in California. One of these is the well-known codlin-moth (Cydia pomonella L.). Another is the green apple aphis (Aphis pomi DeGeer), and the remaining two are scale insects, one the San Jose scale (Aspidiotus perniciosus Corn-stock), and the other the Florida wax scale (Ceroplastes flori-densis Comstock). None of these insects is a serious pest at present. In other countries the fruit is sometimes attacked by the Mediterranean fruit-fly (Ceratitis capitata Wied.) and the Queensland fruit-fly (Bactrocera tryoni Froggatt). In India the anar caterpillar (Virachola isocrates Fabr.) bores in the fruit.
1 Injurious and Beneficial Insects of California.