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Keuchrnius (P. E.). Onderzoekingen en Beschouwingen over eenige 

 Schadelijke Schildluizen van de Kofliekultuur op Java. [Researches 

 and co2isiderations on some Ooccids injurious to Coffee Cultiva- 

 tion in Java.] — Meded. v. h. BesoeJcisch Proef slat ion, Djember, 

 no. 16, 1915, p. 63, 1 fig., 4 plates. 



' In September 1913 the author vasited certain coffee plantations in 

 Eastern Java, which were all seriously attacked by Coccids. These 

 insects are now the most serious pests of all kinds of coffee on the 

 island. One of the reasons for this is that the cultivation of Hevea 

 brnsiliensis is increasing and coffee plantations are often not so well 

 cared for as formerly. The species of Coccids concerned are Coccus 

 {Lecanium) viridis, Saissetia {Lecanium) hemis'phaerica, Pseudococcus 

 adonidum, P. bicaudatus, sp. n., P. citri, Pulviyiaria psiait, Iscknaspis 

 longirostris {fdiformis), and Mytilaspis sp. Of these, the most important 

 are C. viridis, P. bicaudatvs and P. citri, especially the first two. 



Coccus viridis, Green, is described and an account of its life-history 

 given. It was first noticed at the end of the last century in Java 

 on Liberian caffee ; it is miceitain whether it is an indige]ious species. 

 It was first observed in Ceylon in 1882 and, according to Green, was 

 imported with Liberian coffee. lb is now distributed over all tropical 

 countries and, as it thrives on many other plants besides coffee, it is 

 a dangerous pest. The author believes that, contrary to the view 

 expressed by Green, C. viridis is not ov oviparous. A careful study of 

 the rate of movement of the very young hirvae, in search of a place 

 in which to attach themselves, gave a mean speed of 1 metre in 

 45 minutes, which is sufficient to be a very important factor in the 

 spread of the pest. The resting, place preferred is the underside of 

 the leaf and on or close to the central vein, almost invariably with 

 the head turned towards the base of the leaf. The insect probably 

 remains in the same place during its whole life, provided the leaf 

 remains alive. The quantity of sweet exudation produced is greater 

 than in most other Coccids, which increases their attractiveness for 

 ants. In Java reproduction goes on the whole year round and may 

 begin when the insect is 6 weeks old. Zehntner's calculation of the 

 rate of reproduction of Chionaspis saccharifolii is regarded as applicable 

 to C. viridis, i.e., that one female in October may have nearly 20i- 

 millions of descendants by the middle of the following April. In this 

 part of Java there is evidence that C. viridis will live and thrive 

 fairly well at a height of 5,000 feet above sea-level, though under 

 these conditions it is hardly a pest. It is most in evidence at the end 

 of the dry and beginning of the wet season and this unfortunately 

 coincides with the time of most active growth of the coffee plant. 

 The rainy season is unfavourable to the pest ; the heavy tropical rains 

 wash away many of the young larvae and a white fungus attacks them 

 and destroys large numbers. The physical condition of the plant has 

 a great influence on the pest, and if it is weak, the scales do not reach 

 their normal development. When the attack is serious, the growth 

 of the plant is arrested, the flowers are scanty and the fruit sets badly 

 and if attacked by the scale aborts and falls. It is generally believed 

 that the direct cause of these injuries is the incessant sucking of the 

 plant juices, but the author thinks that the injection of harmful 

 secretions into the plant also occurs. The fungus, Cephalosporium 



