9 



The importance of drastic measures against Aspidiotus perniciosus 

 (San Jose scale) is emphasised. Oil emulsion (1 : 15) is a good spray 

 to use when the leaves have fallen, with a second application later if 

 necessary. Spraying should be begun in the autumn, when the scales 

 are young. Crude petroleum emulsion is cheaper than red oil but is 

 less effective. The method of fumigating trees with hydrocyanic acid 

 gas is described. The same treatments may be used to control 

 Lepidosaphes beckii {Mytilaspis pomonim) (apple-bark scale). The 

 abundance of Thrips tabaci depends almost entirely on weather condi- 

 tions. When it is present in great numbers, tobacco water, benzole 

 emulsion, coal-tar water and other sprays have given good results on 

 limited areas, but to cope satisfactorily with this pest on large areas is 

 a difficult matter. 



In discussing the fungous diseases of apple, some hints are given on 

 combining insecticide and fungicide mixtures. 



Illingworth (J. F.). Cane Grub Investigation. — Queensland Agric. 

 Jl., Brisbane, xiv, nos. 3 & 4, September & October 1920, 

 pp. 148-152 and 198-199. 



Among the pests of sugar-cane dealt with is a Lygaeid, Phaenacantha 

 atistralica, Kirk., which is commonly found on native grasses, and has 

 lately turned its attention to sugar-cane. It only increases rapidly 

 during the dry part of the year, and is consequently at its maximum 

 during the cutting season, when the growth of the cane is not materially 

 interfered with. When, however, the bugs are very numerous and 

 suck the under-surfaces of the leaves, they must materially reduce the 

 sugar content, and if at any time they should attack young cane, they 

 will become a serious menace. The habits of this bug greatly resemble 

 those of the chinch bug [Blissus leucopterus]. Hibernation occurs in 

 bunches of grass and rubbish, and the newly hatched nymphs may be 

 found there in April, but they soon chmb into the cane leaves, where 

 they are numerous from June to September. The punctured areas on 

 the leaves become light coloured, then yellow, and finally brown, 

 probably owing to the development of a fungus. When the spots are 

 abundant the whole leaf dries up. In wet seasons the bugs are largely 

 destroyed by a fungous disease. Egg-parasites have not as yet been 

 studied, but several predaceous insects, chiefly Reduviids and the ant, 

 Pheidole megacephala, feed upon the later stages. 



As this pest breeds freely in grassy fields, clean cultivation is 

 recommended, and the burning of rubbish should materially reduce its 

 numbers, as in the case of the chinch bug. 



Oil-Spraying Tests on Apple-Trees. — New Zealand J I. Agric, Wellington, 

 xxi, no. 2, 20th August 1920, p. 78. 

 Oil sprays may be safely used on apple trees in the dormant season. 

 Even when used at a strength of 1-4 no damage was caused to the 

 trees. In cases of growth being retarded owing to stronger sprays, 

 the trees invariably made up the deficiency by the end of the season. 

 Unsprayed trees were badly infested with San Jose scale [Aspidiotus 

 perniciosus] . 



Stratford (G.). Woolly Aphis Control Tests at Papanui. — New 



Zealand Jl. Agric, Wellington, xxi, no. 2. 20th August 1920, 

 pp. 85-86. 

 The results of these tests show that red oil used as a spray at a strength 

 of 1-10 and heated to 120° F. is the most satisfactory insecticide for 



