468 Agriculhiral Journal uf Victoria. 



A FUNGUS PARASITE ON THE CODLIN MOTH. 



(Isaria farinosa (Dicks.) Fr.) 



By D. Mc Alpine. 



I^]arly in October^ when carrying out spraying experiments in Mr. 

 A. F. Tliiele's orchard, at Doncaster, that grower called my attention 

 to the fact that numerous codlin moth grubs were being killed by a 

 white fungus that enveloped them. He calculated that as many as 

 90 per cent, were destroyed in this way, and considered the disease to 

 be of the nature of an epidemic. The zinc bands around the tree- 

 trunks were being removed and examined at the time of my visit, and 

 I obtained a number of dead specimens in order to examine the 

 fungus which appeared as a dense, woolly covering around the bodies 

 of the larvae. In some cases the fungus grew out from the body in 

 the form of slender stalks, expanding at the free end, and in one 

 instance three such stalks were observed about 10 mm*, high, and 

 ending in a club with a white mealy covering. On examining this 

 white material under the microscope, it was found to be a mass of fungus 

 filaments, with numerous projecting Penicillium-like bodies, bearing 

 innumerable spores or conidia as they are technically called, which was 

 the cause of the mealy appearance. The dense, white mould directly 

 covering the grubs, did not show at this stage any of the reproductive 

 bodies. Several of the grubs were placed in damp chambers, not 

 however so moist as to encourage the growth of other fungi, and in 

 about five days there was a profuse development of conidia. The 

 fungus might either be chalky-white or ochraceous, or a mixture 

 of both, but the conidia produced in each case were the same, show- 

 ing that the fungus varied in its colour. At various points, short, 

 thread-like stalks were produced, and it was soon decided that the 

 conidia might either be croduced at the tips of these stalks, or 

 directly from the fungus filaments enveloping the body. Here, then, 

 was an undoubted fungus attacking the codlin moth grubs and 

 destroying them at the stage when they were about to pass into the 

 chrysalis form. It was also found to be capable of reproducing itself 

 freely, and thus a means of spreading the fungus was easily obtain- 

 able if it should be found practicable to destroy the codlin moth in 

 the grub stage by this means. 



Previous Records of Parasitic Fungi on 

 the Codlin Moth 



The codlin moth, like others of its class, has many natural 

 enemies, and these have all received more or less attention at the 

 hands of investigators. T. D. A. Cockerellt in " Preliminary Xotes 

 on the Codlin Moth," has pointed out its natural enemies occurring 

 in New Mexico, and these include: — 1, birds; 2, bats and other 



*A Millimetre is about ^^^ inch. f Bull. 25, New Mexico, Ag. Exp. Sta., Feb., 1898. 



