R. H. Deakin 243 



[f tlic total loss to the planters, caused by this insect attacking young 

 coffee, could be assessed, I think the result would be startling. The 

 ring-barked tree may not die till months later, lience there is an 

 additional loss of time. Many people believe in the growing of maize 

 between the coffee and even in leaving weeds as food for the caterpillars ; 

 they forget that by so doing they are encouraging the moths to lay 

 eggs in their plantations. The remedy lies in clean cultivation and 

 the intelligent use of poison bait. As soon as the value of these methods 

 is emphasized by those in authority the loss will be considerably 

 reduced. 



Pests attackinu Citrus. Citriculture should be an important 

 and remunerative occupation in 15. E. A. in the future and the importance 

 of insects in this connection must not be forgotten. 



Argyroploce leucotreta, Meyr. This is also a pest in S. Rhodesia. 

 It causes extensive damage to the orange crop at the experimental 

 farm at Kabete, B.E.A. The caterpillar, which feeds inside and ruins 

 partly ripe oranges, pupates just beneath the surface of the soil. The 

 eggs are small, flat and scale-like, and are, I believe, laid on the fruit. 

 Experimental spraying of the unripe fruit with lead chromate was not 

 a success, sprayed trees suffering equally with the controls. This was 

 found to be because the minute caterpillar on boring through the 

 surface of the fruit appears to be in a great hurry and merely bites 

 its way below the surface, disgorging the tissue removed — it cannot 

 therefore be poisoned at this stage. My study of this interesting pest 

 was interrupted, but I found in the one or two cases which I examined 

 that the newly hatched caterpillar, before entering the orange (no 

 particular place being chosen), spent some time in the calyx cavity, 

 at the top of the fruit. Does it feed there, and could it be poisoned 

 if spraying were carried out before the calyx cavity becomes closed? 

 (cf. Carpocapsa pomonella). 



A small, unidentified red mite causes a scabbing and silvering of 

 oranges ; the leaves of the tree appear ^o be unaffected. 



Although Icerya purchasi, the Australian bug, occurs in the 

 Protectorate, it does not seem to rank as a pest. It did not appear 

 to thrive on trees which were artificially infected with it, at an altitude 

 of 6000 ft. As showing how healthy crops and trees may suddenly 

 suffer from migratory swarms of insects in Africa, the following case 

 is of interest. A large swarm of small leaf-eating beetles (Halticinae?) 

 suddenly appeared in a citrus orchard where they remained some ten 

 days and did considerable damage to the young foliage. They appeared 



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