.439 



The question of the specific identity of the mites on these plants is 

 considered, and it is suggested that three of the four Enghsh mites, 

 Eriophyes avellana, E. ribis and E. grossulariae are not good species 

 and would be transferable from one food-plant to another. Proof 

 of this has liowever not been obtained. The fact that the mite on 

 the mainland, which is strongly established in the lower Fraser Valley, 

 apparently lives on both hazel and currant, will have a retarding 

 uifluence on the planting of these districts with small fruits, especially 

 black currants ; and it would be inadvisable to let any large area be 

 planted until the fact that this mite will not affect the cultivated 

 varieties of black currant and gooseberry has been proved beyond all 

 doubt. 



VAN Hall (C. J. J.). Carbolineum ter Bestrijding van Ziekten en 

 Plagen in onze Gewassen. [The Use of Carbolineum against 

 Diseases and Pests of our Crops.] — Teysmannia, Batavia, xxxi, 

 no. 3, 1920, pp. 119-126. 



Some of the advantages and disadvantages of carbolineum as an 

 insecticide are discussed. This substance is largely used on the trunks 

 and larger branches, but only rarely on the leaves and twigs, and it 

 is of no importance as a soil disinfectant. A weak point is its irregular 

 quality ; even if each batch is chemically tested, the result will not 

 show whether the material is efficient against the pests and non- 

 injurious to the plants. Another disadvantage is the irregular 

 behaviour of different samples as regards emulsification. In Dutch 

 Guiana an 8 per cent, solution has proved effective against the scale. 

 Coccus {Lecanium) viridis, on Liberian coffee, and it is worthy of note 

 that the foliage did not suffer. Against scales in the Dutch East Indies 

 a trial with an 8 per cent, solution should be made and if the foliage is 

 injured it is best to prune the leaves and twigs prior to spraying, 

 when a stronger solution — of 10 or even 20 per cent, strength — may 

 be used with impunity. 



It is important that only such carbolineum be used as yields a milk- 

 white or dirtv white solution in water ; a light brown or light violet- 

 brown colour denotes a quality unsuitable for spraying plants. 



VAX Hall (C. J. J.). Derris als Insecticide. [Derris as an Insecticide.] 

 — Teysmannia, Batavia, xxxi, no. 4, 1920, pp. 159-166. 



The chief part of this paper is taken from one recently noticed [R.A.E, 

 A. vii, 496]. There is also a reference to a short article, issued by Wood 

 in 1912 {Agricultural Bulletin Fed. Malay States, i, p. 164), which 

 recorded the successful application of derris against ants and cabbage 

 caterpillars. About 2 lb. of the root were crushed by beating, 1 gal. 

 of boiling water was added and 1 part of the decoction thus obtained 

 after a few hour's soaking was diluted with 8 parts of water for use. 



Reyne (A.). Bestrijding van den Cacaothrips. [Measures against the 

 Cacao Thrips.J — Meded. Dept. Landbouw Suriname, Paramaribo, 

 no. 15, 12th December 1919, 3 pp. [Received 10th August 1920.] 



Owing to the lack of a practical method nothing has been done 

 hitherto to combat Heliothrips rubrocinctns, Giard, which is the most 

 serious insect pest of cacao in Dutch Guiana. It is a primary pest 



