454 



borer), and Gryllotalpa sp. (mole-cricket), spraying with kerosene 

 emulsion and extract of derris root was tried with uncertain results ; 

 lamp traps were emplo3'cd with some success against the stem-borers 

 and mole-crickets. 



Froggatt (W. W.). a New Mealy Bug on Citrus Trees {Pulvinaria 

 ornata, n. S!^.).—-Agyic. Gaz. N.S.W., Sydney, xxxii, pt. 6, June 

 1921, pp. 427-428,^1 plate. 



Pulvinaria ornata, sp. n., was found in all stages of development 

 on the foliage of a lemon tree near Sydney, and also heavily infesting 

 the foliage of Piltosporion tmdiilaium, near the lemon tree. It is 

 assumed that this bush is the original host of this Coccid. 



Of the Pulvinaria, the most common and widely distributed is 

 P. psidii, which is found on guavas in the Sandwich Isles ; onguavas, 

 figs and Eugenia in the Philippines ; and on guavas, mango, tea and 

 coffee plants in Southern India. The plants are covered with cotton 

 ovisacs, and much honey-dew is produced. P. tecta is known to feed 

 on orange foliage in Sydney, and on Acacia and Davesia near Sydney 

 and Melbourne. In Ceylon, citrus fruits are infested with P. cclUdosa. 

 The new bug here described closely resembles these three species, 

 especially the latter. 



Illixgworth (J. F.). A Study o! Natural Methods oJ Control for 

 White Grubs. — Queensland Bur. Sugar Expt. Sta., Brisbane, Div. 

 Ent., Bull. 12, 1921, 20 pp., 5 figs. [Received 21st July 1921.] 



Investigation into the condition of white grubs in sugar-cane areas 

 in Queensland showed that, on the estate examined, about one-third 

 of the grubs had recently succumbed to Muscardine fungus [Meta- 

 rrliizium anisopliae]. In consequence of this discovery it was decided, 

 towards the end of 1918, to try artificial propagation of the spores. 

 The method of propagation is described : maize meal and sliced sweet 

 potatoes proved the best media for cultivation. The results of inocula- 

 tion of fields with the fungus were, however, very inconclusive, largely 

 owing to the fact that a real epidemic of the fungus occurred in 1920 

 in all the grub-infested area, .so that the majority of the grubs were 

 killed without any artificial assistance. Under normal conditions 

 the grubs descend into the soil for hibernation in March or April, 

 before the cool weather sets in, and when they are thus located, cleep 

 in the moist sub-soil, they seem to be fairly immune from diseases. 

 Investigations showed that mortality increased with the lowering of 

 the temperatvn"e, and was also stimulated by moisture ; both of these 

 factors were present during the 1920 epidemic. It was also found that 

 the fungus was well distributed in all the areas regularly attacked by 

 grubs, but did not occur outside this well-defined region. Appar- 

 ently, the disease spores persist in the soil, ready to bring about an 

 epidemic when conditions are favourable. It is therefore likely 

 that the action of the fungus can easily be increased by irrigating the 

 fields, especially after cool weather sets in, which is usually in the dry 

 season. 



Another cause of mortality among the grubs is a bacterial organism, 

 apparently the same as that previously described as Micrococcus 

 nigrofaciens. It is difficult to gauge the rate of mortality from this 

 disease as the affected grubs quickly decompose and disappear. 

 Bacterial contagion is far less destructive than Muscardine fungus 



