8 A STUDY OF XATUEAL METHODS OF 



In our most comprehensive experiment, 10th February, 1920, the 

 spore-laden material from the cabinet was applied in a field at Greenhills 

 by placing it in drills made with a pony-plough close alongside the stools 

 of cane. This was just about the time the young grubs were hatching. 



On 27th February, 1920, a further trial Mas made by using a quantity 

 of this pure culture material under individual stools, in a grubby field at 

 Meringa. 



A. After digging the soil away from the stool to a depth of about 



6 inches, we replaced fourteen first- stage grubs of 

 Lepidoderma albohirtum in the bottom ; after covering 

 slightly, a small quantity of the spore-dust was placed 

 on the soil and covered. 



B. This second stool was prepared in the same way, except that 



the spores were dusted directly on to seven first-stage 

 grubs of L. albohirtum. before covering the soil. 



c. Six third-stage grubs of Lepidiofa frenchi were dusted with the 

 spores before covering in with soil. 



D. Twelve third-stage grubs of the same species were thoroughly 

 dusted wdth the spores in this fourth stool, before covering. 



16th March, 1920 — All the above stools were dug out and the soil 

 carefully searched for evidence of the action of the fungus on the grubs. 

 In each case we dug a considerable area about the stool, trying to locate 

 the grubs, which had largely disappeared. The results follow : — 



A. We found six L. albohirtum grubs, four in the first stage and 



two in the second. There were no indications to show 

 what had become of the others, and no sign of the fungus. 



B. None of the grubs could be located. The drier portions of 



the old stool were somewhat mouldy, as if affected by 

 the fungus. 



c. None of the grubs could be located. 



D. There was an ants' liest {Pheidole megacephaJa) in the soil near 

 the stool. One grub was found dead and eaten out by 

 these ants, a fact which may be suggestive as to the 

 disappearance of those in the other stools. Two other 

 living healthy third-stage grubs were all that remained 

 of the twelve that we had placed there. 



These results were most discouraging, for I did not find a single 

 grub showing signs that it had been killed by the fungus. It was rather 

 stiange, however, that the grubs disappeared as thoy did. Of course, they 

 may have travelled away to other stools, though this does not appear to 

 be their habit, especially when the soil is in such a dry condition. It is 

 just possible, however, that the ants got them as fast as they became 

 diseased, and removed their bodies. At any rate, these results were far 

 from satisfactory. 



