W. J. DOWSON Oo 



ditions, the suddenness of the withering, the rapid disorganising of the 

 cortical tissues and the presence of the three parasitic fungi mentioned 

 above. 



The insect pests of coffee are more serious than are the parasitic fungi, 

 and mention may be made of at least two which have been computed to 

 cause more annual loss than perhaps any other disease to which coffee 

 is subject. The variegated bug, Antestia lineaticollis Stal., has been known 

 almost from the commencement of coffee planting throughout Africa. 

 The insect punctures all the young growling parts of the tree, but chiefly 

 the very young flower buds which are formed in whorls in the axils of 

 the leaves. The result is a non-formation of flowers and a proliferation 

 of shoots in their place, thus bringing about an almost total failure to 

 set fruit and causing much additional labour and expense in pruning. 

 Antestia also pierces and sucks the green berries producing a stain upon 

 the kernels which considerably lessens their market value. As is usual 

 with such insects, spraying either with a stomach poison or a contact 

 insecticide is of no avail. The bug is active and either hides under leaves 

 and crevices, or flies to the ground where it becomes invisible owing to 

 its colour. In the past the usual method of combating this pest was 

 the collecting by hand of the bugs, but recent knowledge of the life- 

 history has indicated a more effective way of controlling the numbers of 

 the insect. The eggs are laid in clusters of a dozen on the underside of 

 the leaves and are normally pearly white in colour. A large number of 

 eggs are not white but grey, and out of these hatch out, not young 

 Antestia bugs but minute chakids. Two species of these have been dis- 

 covered which parasitise the eggs of Antestia, and it has been found pos- 

 sible on the Government Experimental Farm near Nairobi to breed the 

 parasites in the laboratory in such numbers as to completely check the 

 increase of Antestia. It is hoped in time to be able to distribute the 

 parasite early enough to those plantations which show signs of the pest 

 to prevent the insect from doing appreciable harm. 



Another serious insect pest is comparatively new, having first made 

 its appearance in 1915, and is a species of Diatkrothrips {D. coffeae Will.). 

 This minute insect appeared in the dry season of 1915 in clouds, and, 

 settling upon the coffee trees of a plantation close to Nairobi, sucked 

 every green part almost dry, producing a conspicuous silvery appearance 

 of the foliage. The trees were entirely defoliated, and in some instances 

 killed. From the Nairobi area the pest gradually spread in a north westerly 

 direction and is approaching Uganda. As in the case of Antestia, no 

 known spraying fluid is of the least avail, for at the first contact of an 



