82 AUSTRALIAN SUGAR-CANE BEETLES AND THEIR ALLIES. 



2nd July, 1920, 1 had a communication from a grower at Hambledon. 

 who urged me to introduce a species of Fittosporum from Victoria, for 

 he contended that it acted as a death-trap to the beetles, that they died 

 soon after alighting on the foliage, and the dead beetles were seen on 

 the ground. Since several species of this genus are recorded by Bailey 

 in North Queensland, no investigation was made of this matter. 



Considerable has also been written on the poisoning of stock Ijy 

 sorghum, and this plant has freciuently been recommended as a green 

 crop for grubby land. The management of Goondi ]\Iill made some 

 investigation during 1909 (39), but the trials gave no results. Subse- 

 quent trials in the Innisfail district also showed that there was no 

 noticeable result upon the grubs, more than what would result from the 

 application of any green crop. 



CULTURAL MEASURES. 



There is no question that intelligent cultural measures go a long 

 way toward saving our crops from the ravages of grubs. Hence, 

 throughout my investigation I have given special attention to these 

 factors in control; they have been developed along the following lines: — 

 (1) Ploughing during summer, (2) planting methods, (3) stimulating 

 vigour in the plant, and (4) ploughing out infested crops before the 

 grubs hibernate. 



(1) When the beetles are ready to oviposit they naturally seek out 

 areas covered with growing cane or other grasses ; hence if the fields are 

 in clean fallow and are being ploughed at that season, preparatory to 

 early planting, there is little opportunity for the beetles to infest them. 

 And even where the beetles do oviposit more or less on such land, being 

 attracted by bunches of grass and weeds that have escaped the ploughs, 

 subsequent ploughing has a tendency to eradicate them. This method of 

 checking the grubs was successfully pursued at Farleigh Plantation, 

 Mackay, many years ago. Mr. F. W. Bolton (2) said that the grubs had 

 been extremely numerous seven years before, but that they had got rid 

 of them by ploughing the paddock up in the face of summer. The land 

 was then left to fallow for a season, and given two subsequent cross- 

 ploughings. Being thus kept on the go without cropping the grubs were 

 completely eradicated. In another instance (7) where similar conditions 

 prevailed, there was like success. 



As to methods of planting in their relation to grub control, I wish 

 to compare early and late operations, and also call attention to the 

 benefit of deep drills, deep-rooting varieties, choice of plants, and spacing. 



(2) In my monthly reports I have said much on the subject of late 

 planting; really, in farm practice it has much to commend it. The soil 

 can be most easily prepared a^ul rid of couch and other troublesome 

 grasses during the dry season, &c. ; yet my main idea was to facilitate 

 thorough cultivation during the flight and ovipositing of the beetles. 

 Though we have learned since that the eggs are deposited much deeper 

 than we had formerly supposed, usually far below ordinary cultivation, 

 especially in the loose red volcanic soils, I siill maintain this is a valuable 

 factor. The benefit, however, does not come so nuich from the destruction 

 of the eggs, but is i)robably due more largely to the increased vigour 

 which it stinnilates in the plant. This phase of the problem is dealt 

 Avitli in another section farther on. 



