329 



and become transformed into small spheres, and it is then that in- 

 tensively active phagocytosis begins. The bacteria enveloped by the 

 phagocytes are digested with great rapidity. 



The injection of a weak dose of an old culture of dysenteric baciUi 

 also confers immunity on a larva against otherwise fatal doses. 



VAN Hall (C. J. J.). Ziekten en Plagen dcr Cultuurgewassen in 

 Nederlandsch-Indie in 1919. [Diseases and Pests of Culti- 

 vated Plants in the Dutch East Indies in 1919.] — Meded. Inst. 

 Plantenziekten, Biiitenzorg, no. 39, 1920, 50 pp. 



The pests recorded include a Coccinellid, Epilachna sp., attacking 

 potatoes ; the larvae of Heliothis sp., infesting Arachis [hyjjogaea] 

 (ground nut) ; and the sweet potato weevil, Cylas formicarius {turci- 

 2)emiis). 



The forest pests, Duomitus [ccraynicus], Calotermes [tectonae], Zeuzera 

 [cqffeae], Hypsipyla sp., and the ring borer, Phassus danwr, occurred 

 as usual. The unidentified species of Xyleborus infesting teak, men- 

 tioned in the previous report [R.A.E., A, vii, 388] proves to be 

 X. destruens [R.A.E., A, vii, 536] ; this beetle attacks gro^^dng teak and 

 there are indications that this infestation must have been of long 

 standing. Leaf caterpillars, including Achaea {Ophiusa) serva and A. (0.) 

 melicerta, defoUated guttapercha trees {Palaquiuni). Larvae, probably 

 those of a beetle, Dichodontus croesus, destroyed a group of Vernonia 

 <irborea trees. 

 L Cacao suffered httle injury from the cacao moth [Acrocero])s cra- 

 merella], contrary to what occurred in the previous year. 



Cassava was attacked by mites [Tetranychus bimaculatus] and ter- 

 mites. Green vegetables were infested by various caterpillars, 

 Agromyza phaseoli and Aphis medicaginis. 



Hevea was infested by Coptotermes gestroi, Lymantrid caterpillars, 

 Acantho psyche snelleni, Pseudococcus citri, Holotrichia lencop>hthalma 

 and Lepidiota stigma. 



Cotton was almost free from attack by Earias fabia. 



Kedele [Glycine soja] suffered considerable injury from the pod 

 borer {Etiella zinckenella), the stem borer {Agromyza sojae) and the 

 ■catjang borer {A. phaseoli). The last-named fly seems more injmious 

 at certain times ; on one estate where planting was done on five 

 separate dates with 15-day intervals, it was only the fifth lot that 

 was badly attacked. A CoccineUid Epilachna sp., another beetle 

 Araecerus sp., and caterpillars — including those of Heliothis— aho 

 infested G. soja. 



Cinchona pests included Helopeltis antonii var, bradyi, the cater- 

 pillars of Euproctis flexuosa and Attacus atlas, a scale Coccus (Leccmium) 

 hesperidum, and the mites, Tetranychus bimacidatus and Brevipalpus 

 obovatus. In spite of the prolonged dry weather many seed-beds in 

 the government cinchona plantations were free from mites. 



Coconuts continued to be infested by Brachartona catoxantha. 

 Hidari irava was a serious pest on one estate. Limacodid caterpillars 

 and those of Amathusia phidippus did httle injury. Oryctes rhinoceros 

 and Rhynchophorus ferrugineus occurred everywhere, but on the east 

 coast of Sumatra they did httle damage owing to the measures sys- 

 tematically adopted, A caterpillar, thought to be that of Setora 

 nitens, occurred in a number of locaHties, but not much damage was 



