A disease known as " leaf-rot," rather prevalent in Mysore, is distinguished from the above, and is referred to a fungus named Pellicularia Ifoleroga, by Dr. M. C. Cooke. It appears about July, when the leaves of affected shrubs become covered with slimy, gelatinous matter, turn black, and drop off ; clusters of berries also rot and fall. There is every probability that the sulphur and lime treatment would be effective in this case also. The shed leaves and fruit should be collected and burned.
Fly.—This disease has been known for many years in Dominica and Brazil; it has also spread to Venezuela, the Antilles, Porto Rico, Martinique, Trinidad, and all down the Atlantic coast of South America. It is caused by the larvae of a moth, scarcely in. long, named Cemiostoma eoff Mum. The oolour of the insect is dull-white or pale-grey, with a bar of black across the posterior end when quiet ; its motions are very active, and it readily takes alarm. The female is either provided with BM ovipositor of srufficient strength to pierce the cuticle of the leaf, beneath which the egg is deposited, or it deposits the egg in some irregularity on the surface of the leaf, leaving the future caterpillar to find its own way into the tissue. In either case, a caterpillar develops from the egg, and feeds on the cell tissue of the leaf, in all directions, between the two cuticles. The insect prefers young and delicate leaves, and is most active about the commence ment of the wet season, when, doubtless, the majority of the eggs are deposited. It is dormant during the wet season—say from March to May Of the varieties of coffee met with in Dominica, the mocha is most subject to the attacks of this moth, its leaves being the most delicate. Stronger leaved varieties, when fairly healthy, are scarcely attacked ; but when existing under unfavourable conditions, such as to induce flaccidity of texture, they are sometimes much affected. The disease manifests itself by the appearance of large discoloured blotches on the leaves, causing their decay and fall. It has been stated that, by picking the leaves at such a time as to take the greatest number of the larval when about two weeks old, it would be easy to destroy the pest, as the size of the blotches would then easily distinguish the diseased foliage. The insect is very susceptible to the effects of wood smoke, and may easily be driven off or destroyed by the smoke of ordinary wood or grass fires. At present it does not exist iu the West Indies to such an extent RS to injuriously affect the fruitfulness of the trees, and is markedly loss numerous where inseetivorons birds abound.
Borer.—This pest, formerly known as the " worm '' and "coffce-fly," is most troublesome in Southern India, especially iu Coorg and the Wynaad, where, in 1865-6, it destroyed whole estates. Beetles with similar boring habits infest the coffee bushes on the West Coast of Africa, and in Zan zibar, and are occasionally troublesome in Jamaica. The Indian borer has been identified as the Xylo trechus quadrupes. In its complete stage, the insect appears as a winged beetle ; it is to in. in length ;
rather finer in shape than a wasp ; with a hard, shiny coat ; in colour, red and black, or, in other cases, yellow and black, in alternate transverse lines. It bores a passage into the stern of the coffee tree, usually at some few inches above the ground. This passage, at first horizontal, soon takes an upward spiral direction, and proceeds until a safe retreat is found, in which the larva may be deposited. The tree soon droops, and dies down to the point at which the entry has been effected, and where it can be easily broken off by a sharp pull at the upper part. The only course is to break off the tree in this manner, and then to burn the stem, with the larva secreted in its centre. Young shoots will proceed from the stump (if the perforation has not begun too near the roots), and one of these may be trained to succeed the original stem. There is a growing impression that the borer can be kept out of estates in bot, dry situations only by providing shade, and perhaps irrigation, Its ravages have always been worst on weedy plantations and new clearings.
Bug.—The coffee tree is attacked by various species of Coccidce in most counties, where they are known by different names. Ceylon has been, perhsps, the worst sufferer in this respect ; but careful cyltivation has greatly reduced the evil. There are two distinct species of bug found in Ceylon, and called respectively " black," or " scaly," and " white," or " mealy." The former, Lecanium coffees, is a minute insect, whieh attaches itself to the tenderest shoots of the plant ; the females have the appearance of small scollop shells, of a brown colour, and adhere to the leaf or twig in the same manner as the scollop shell to a rock. Each of these contains several hundred eggs undergoing incubation ; and in a short time, the whole of the green wood of the tree will become covered with the young insects, and coated with a black soot-like powder, which renders the tree easily discernible at a distance. The bug will soon spread over whole estates, entirely checking the growth of the trees ; the fresh young shoots are slways first attacked, and such wood as is allowed to mature produces hardly any crop. The berries, moreover, are, in their earliest stage, destroyed by these insects, which cut them off at the stalk. The measures recommended for checking this scourge are to dust the bushes with a mixture of pounded saltpetre and quicklime, in equal parts ; or to brush or sponge the affected parts with a mixture of soft-soap, tar, tobacco, and spirits of turpentine, in about equal quantities. A coolie, with a bucket and a piece of rag, can perform the office effectually. This species affects elevated (above 3000 ft.), cold, damp, close localities, where it is found in all stages of development all the year round, the propagation being oontinuous. It generally makes its first appearance under the shelter of a large rock, near a belt of forest, or at the bottom of a nullah.