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41 \ r/>AK ^^:o' )9I9 -^ 



Bernard (C.) & Keebosch (M.). Mijten Antastingen op Kina, Thee 

 enz. [Mite Injury to Cinchona, Tea, etc.] — Meded. Pro^station 

 voor Thee, Buitenzorg, Ix, 1918, 16 pp., 7 plates. 



The four mites dealt with in this paper are Tetranychus telarius, L. 

 {biirmculatus, Harv.), T. biocuJatus, W.-M., Tarsonemus translucens, 

 Green, and Brevipalpus obomtus, Donn. It is believed that the present 

 is the first record of the occurrence of the two last-named on cinchona. 

 T. telarius has not yet been found on tea ; it has been observed on 

 Manihot , Ricinus, Cinchona, Hevea, Papaya and Clitoria, and to these 

 must now be added two Leguminosae used as green manure plants, 

 Desmodium tortuosmn and Sesbania aegyptiaca. Infested young 

 cinchona plants are stunted and deformed, and the older leaves are 

 curled, while the younger ones shrivel up. T. biocuhtus is less poly- 

 phagous than the preceding species. Though common on tea it does 

 not appear to do serious damage in Java, where it also occurs on coffee 

 and Ixora spp. B. obovatus is a serious pest of tea in Java. It has 

 also been observed to infest severely a species of Jasminum sometimes 

 grown as an ornamental plant on tea and cinchona estates. Tarsonemus 

 translucens, which did rather serious injury to tea during the past 

 dry season, must now be considered as also a serious pest of 

 cinchona, the leaves of young plants being curled and shrivelled 

 by it. The injury due to Tarsonemus translucens is increased by 

 infestation by thrips. 



It is not advisable to allow these four mites to increase unchecked, 

 and direct measures are desirable. The latter are facilitated by the 

 fact that infestation is chiefly confined to cinchona in seed-beds. 

 In addition it is advised that during the wet season the plants should 

 be removed from the seed-beds and planted out, when their more 

 vigorous growth is held to be an important factor in causing the 

 pests to disappear, probably because the leaves of the larger plants 

 are unsuitable as food. Successful results were obtained by spraying 

 the seed-beds with a saponin solution or by dusting with sulphur. 

 The saponin solution is prepared by boiling 10 oz. of the fruit of 

 Sapindus rarak in 3| pints of water for half an hour. After straining, 

 this concentrate is diluted with 10-15 volumes of water to form the 

 spray solution, which is apphed every three days. In dusting, from 

 5 to 10 gms. (about ^-J oz.) of sulphur is used per square metre (about . 

 10^ square feet), the bed being watered previously. Neither method 

 kills all the mites j^resent, but the practical result is satisfactory. 



Ult]ee (A. J.). Verslag over het Jaar 1917. [Report of the Besoeki 



Experiment Station for 1917.] — Meded. Besoekisch Proefstation, 

 Djember, no. 27, 1918, 24 pp. 



Experiments made by Mr. P. E. Keuchenius with a trap-bait used 

 in British India against tobacco moths {Prodenia, Agrotis, Heliothis) 

 were unsuccessful. The formula used was : Water 200 parts by weight, 

 cane or Java sugar 400, alcohol 3, ethyl acetate 3, Experiments made 

 to determine if the usual quantity of carbon bisulphide could be 

 safely reduced when fumigating tobacco have already been dealt 

 with [see this Revietv, Ser. A, vi, p. 224]. 



(C538) Wt.P2/137. 1,500. 2.19. B. &F.Ltd. Gp.11/3. A 



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