313 



Tortrix. Cinchona growers are complaining of the damage done by 

 an undetermined " bag-worm." Pepper corns are bored by an 

 unknown pest, and Hevea branches have been killed in serious 

 quantity by a Bostrychid. A species of Gunda has almost stripped 

 the leaves of Ficus in the Government plantations, and caterpillars 

 of Ocinara waringii have done much damage to other crops. Hevea 

 and Ficus have suffered seriously from Cyrtacanthacris {Acridium) 

 melanocorne ; Castilloa resisted attack, and Rohusta coffee was not 

 greatly affected. 



RoEPKE (W.). De Praktische Toepassing der Motparasieten. [The 

 practical emplo\Tnent of the (Cacao) Moth Parasite.] — Meded. 

 Proefst. Midden-Java, Batavia, no. 18, 1914, pp. 25-27. [Received 

 4th March 1915.] 



As the season for plucking cacao nears its end, the numbers of 

 Acrocercops cramerella steadily increase. On those plantations on 

 which the moth parasites are numerous the damage is not so great, 

 though the control exercised by them cannot be considered complete. 

 The percentage of parasites rises with the increase of the moth towards 

 the end of the plucking. At the moment when the " rampassen " opera- 

 tions [see this i?ei'2'e?(', Ser. A, i, p. 57] begin, a large number of parasites 

 should be present in the last-infected cocoons, which will emerge in a 

 few days. As the adult parasites are long-lived, the females, w^hich 

 appear first, living at least six weeks, at the end of the rampassen 

 many thousands of parasites should be present, as against the small 

 number of cocoons which have been overlooked on the pods. 



But for the presence of hyperparasites, the parasites might be 

 released in plantations without further consideration. Means must, 

 however, be taken to secure a maximum of parasites during, and 

 especially towards the end of, each plucking, and per contra to keep 

 down the hyperparasites at these periods. Laboratory studies have 

 shown how this may be accomplished. The test must be made on a 

 plantation in which the parasites already exist. A number of native 

 boys who have been previously instructed in moth-cocoon collecting 

 are set to work in the plantations. Collections are made about every 

 sixth day in the same area and the cocoons taken to a central station 

 and sorted by an expert into parasitised and non-parasitised, and the 

 percentage calculated. For control purposes, all the non-parasitised 

 cocoons are kept in special cages until the moths emerge, the greatest 

 precautions being taken against their escape. The parasitised cocoons 

 are sorted into parcels of 10, which are laid out on white paper and 

 covered with a tumbler. Each plantation should have 250 or more 

 such glasses in readiness and a specially constructed rack so arranged 

 as to make full observation easy. Ever}^ day a number of parasites 

 emerge, and the observer in charge notes on the white paper each day 

 the number, species and sex, and allows them to escape, the cocoons 

 being then destroyed. As the hyperparasites emerge, they will be 

 more or less visible under the glasses, and the observer must give his 

 undivided attention to them, as emergence is almost constant. They 

 must be immediately dealt with by stupefying with a wad of wool 

 soaked in gasoline, and, after examination with the lens and deter- 

 mination of sex, destroyed. As a rule, all the parasites will have 



