86 



Up to the present in tlu' field liand-picking and spraying with Paris 

 green liave been tried bnt luu'e proved ineffecti\e, as is shown by the 

 steady increase of the caterjiillars. A careful stud}^ on the spot of the 

 most modern American practice as regards methods and plant is needed. 

 Meanwhile the lead arsenate and soap spray may be used for the two 

 first applications in the field ; for the third and subsequent applications 

 less lead arsenate must be employed, as the older plants sometimes seem 

 liable to become scorched. Even so low a strength as | per cent, has 

 been used with success. 



Injur}' in the drying sheds may be checked either by fumigating 

 the leaves or by examining them for caterpillars. No definite data 

 can be given on these points at present. 



Trap-crops should be tried, and the author suggests beds of tobacco 

 between the fields and the jungle. These must be ready before the 

 seedlings are planted in the fields ; by keeping them stocked with 

 plants younger than those in the fields, their attractiveness is en- 

 hanced. The trap-beds should be protected by poisons ; then spraying 

 must be discontinued, and the poison washed off by watering. After 

 a 14-day interval (during which the caterpillars cannot attain maturity) 

 the plants may either be burned or twice sprayed with a powerful 

 poison. After the latter has acted it should be washed off the plants, 

 and another 14-day interval must be allowed to elapse. This process 

 may be repeated as long as the traps continue attractive. 



In order to reduce the number of caterpillars during the 8 months' 

 when tobacco is not grown, it is necessary immediately to remove 

 and destroy the plants from which the leaves ha\'e been harvested, 

 as these constitute foci of infestation dangerous to the ne.xt crop. 

 Trap-crops of tobacco grown for a period of 3 months before the tobacco 

 season begins will also serve to reduce the total number of pests. 



Palm (B. T.) & Mjop.erg (E.). Bestrijding van Rupsenvraat in Deli- 

 Tabak. i. Effectieve Bescherming van Zaadbedden tegen Vraat. 



Measures against Catei-pillar Injury to Deli Tobacco, i. The 

 eflective Protection of Seed-Beds against Attack.] — Deli Proefst., 

 Medan, \'lugschrift no. 2, October 1920, 4 pp. 



This method of protecting tobacco seed-beds by spraying with an 

 emulsion of lead arsenate and soap is the same as that described in the 

 preceding paper. Instructions for preparing the spray are gi\'en. 



Smits ^•A^ Burgst (C. A. L.). In Nederland waargenomen Parasieten 

 van de gestreepte Dennenrups (Trachea piniperda, Panz. = Panolis 

 griseovafiegata, Goeze). iParasites of the Pine M<Hh, Panolis 

 jiammea, Schiff., in Holland.] — Tijdschr. Plantenziekten, Wageningen, 

 xxvi, no. 11, November 1920, pp. 201-207. 



The following additional parasites of Panolis flauunea, Schiff. {pini- 

 perda, Panz.) R.A.E., viii, 226] are recorded from Holland: — 

 Amblyteles rubro-ater, Ratz., Phygadeuon vagans, (}rv., P. nubilipennis, 

 sp. n., Angitia tenuipes, Ths., and Aphanistes armatus, Wesm. 



Hyperparasites are : Hemiteles casfaneus, Tasch., H. pedestris, E., 

 two other species of Hemiteles, Astiphromma streniium, Holmgr., and 

 two Chalcids. In the author's opinion their importance has been much 

 o\errated, as they do little except towards the end of an outbreak. 



As material was not received from all the infested districts there 

 may be other parasites, and for this reason it is not possible to state 

 the percentage of parasitised caterpillars. Hymenopterous parasites 



