Lecanium coffem, a genus of the order Hemi ptera, appears on the young shoots and buds, like small, wart-like bodies. Each of these warts is a transformed female containing about 700 eggs, which are hatched within it. When the young ones come out of their nest, they may be observed running about and looking like wood-lice. Shortly after being hatched, the males seek the under sides of the leaves, while the females prefer the young shoots as their place of abode. The larvae of the males undergo transformation in pupa beneath their own skins ; their wings are hori zontal, and their possessing wings may probably explain the fact of the comparatively rare presence of the male on the bushes. The female retains her power of locomotion until nearly her full size, and it is about this time that her impregna tion takes place. Each tree on which this hug makes its appearance should be well dusted with a mixture of pounded saltpetre and quicklime in equal parts ; by sponging the parts affected with a mixture of soft soap, tar, tobacco, and turpentine. Another species of Lecanium, in another country, put a stop to the cultivation of the orange as an article of commerce. — Tennent's Ceylon, pp. 4, 46.
The coffee tree is supposed to have been brought to Ceylon about the middle of the 17th century. The first regularly worked estate was opened in 1825 ; but the bug does not seem to have appeared in large quantities till 1845, when, however, it began to spread with such rapidity that in 1847 a very general alarm was taken by the planters, about the same time that the potato, wine, and olive diseases began to create alarm in Europe. The coffee bug seems, however, to be indigenous in Ceylon, for the white bug ilas been found in orange, guava, and other trees, as also on beet root and other vegetables ; and the brown bug attacks the guava, hibiscus, Ixora, Justicia, and orange trees,—indeed, every plant and tree and even the weeds on a coffee estate, particularly such as are in gardens.
Heliothis armigera is an insect of the family Noctuidas, which, in the seasons 1877-78, in in numerable hordes attacked the coffee crops of Shahabad and Patna. It is equally destructive to the cotton crops. It eats into the capsules of the coffee and cotton. The pupae become entrapped in the capsules. Its attacks on the coffee plant are principally in February and March. Careful hand-picking is the sole remedy.
Heliocopis cupido or Deprescaria gossypium attacks the cotton plant ; it is the Toka of Hin dustan.
The larva of the Gracillaria coffeifoliella mines the coffee trees. It is very common.
Hemileia vastatrix, the coffee leaf disease, or leaf fungus, has for several years seriously affected the coffee trees of the island of Ceylon. Though requiring careful inspection for its detection, it was present upon all the coffee trees examined about 1879. With the help of the microscope, it is found at all times to prevade the greater part of the stems and older leaves, in the form of very fine branching filaments, its effects being apparent in numerous somewhat translucent spots, which may be observed when holding one of the older leaves against the light. The direct injury so
caused to the coffee tree is, however, very slight, as compared with the effect produced when the fungus attacks the young leaves, causing them to fall prematurely. The presence of the fungus filaments in such abundance on the outer surface of the tree is quite sufficient account for phenomena which it was first thought must be attributable to a poisoning of the juices of the tree, by an absorption of the fungus matter through its roots. The latter idea must therefore be given up, and the disease considered as external, except when it appears within the tissue of the young leaves. Subsequently, from these enclosed masses of filaments short branches are produced, which emerge from the pores, and bear the conspicuous orange-coloured spores or reproductive bodies. Some of these spores have been observed to germinate on the outside of the leaf, producing branched filaments of exceeding tenuity, which grow with marvellous rapidity all over the surface of the leaf, and beyond to the stems. The ends of some of these filaments, too, have been observed to enter the pores of the leaf, to form fresh disease spots and fresh crops of spores. The true Liberian coffee is said to be of hardy habit, and more able to resist the ravages of this disease.
The caterpillars found on the coffee trees of Ceylon are Orgyia Ceylanica, Euproctis virguncula, Trichia exigua, Narosa conspersa, Limacodes graciosa, and a species of Drepana, but they do not cause much injury. One caterpillar, however, the Zeuzera coffees, destroys many trees, both young and old, by eating out the heart. It re sembles the caterpillar of the great moth of Eng land, and is as thick as a goose quill. It generally enters the tree 6 to 12 inches from the ground, and makes its way upwards. The sickly drooping of the tree marks its presence. Caterpillars of the Boarmia leucostigmaria and B. Ceylanica, also those of Eupithecia coffearia, are found on coffee and other trees in Ceylon from September to December. Seine Ceylon caterpillars sting. A greenish one, that occupies the Thespesia populnea (Suriya, Sinn.), at a certain stage of its growth, descends by a silken thread, and hurries away. The moth of this is supposed to be a Bombyx, named Cnethocampa, Stephens. Another, short, broad, and pale-green, with fleshy spines, that feeds on the Carissa jasminiflora, and stings with fury, is of the moth Necera lepida, Cramer (the Limacodes graciosa, West.). The larva of the genus Adolia are hairy, and sting with virulence. Many exactly resemble in tint the leaves they feed upon, others are like little brown twigs, and many are so strangely marked or humped, that when motionless they can hardly be taken to be living creatures at all.—Tennent's Ceylon. See Larva.