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Brann (F. R.)- Spray versus Fumigation in the Control of Gray Scale 

 on Citrus Trees in Tulare County. — Mthlij. Bull. Cat. State 

 Commiss. Hortic, Sacramento, viii, no. 3, March 1919, pp. 104- 

 107, 1 fig. 



As a result of various experiments the author advises fumigation 

 (especially with liquid hydrocyanic acid) in preference to sprapng, as 

 a remedial measure against Coccus citricola, Camp, (grey scale) on 

 Citrus. Arsenate sprays not only exterminate the Coccinellid enemies 

 of the scale, but also cause the leaves to drop. 



Phillips (E. F.). The Control of European Foulbrood. — V.S. Bepi. 

 Agric. Washington, D.G., Farmers' Bull. no. 975, 16 p., 1 fig. 



Less drastic methods are required for dealing with European than 

 with American foulbrood in bees. In this bulletin the symptoms of 

 the disease are described and special paragraphs are devoted to 

 the basis of treatment, preventive and remedial measures. 



Theobald (F. V.). Apple Aphides. — Jl. Bd. Agric., London, xx\"i, no. 

 1, April 1919, pp. 63-71. 



Of the eight Aphids known to attack apples in Great Britain, the 

 three dealt with in this apper are : Aphis malifoliae, Fitch (blue or 

 rosy apple aphis), Aphis pomi, De G. (green apple aphis) and Siphon- 

 aphis padi, L. {Siphocoryne avenae F.) (oat apple aphis). All three 

 the spend winter in the egg-stage on apples or pears, and these hatch 

 about April ; Aphis pomi has been known to hibernate on thistles 

 {Garduus). 



The young of A. malifoliae live in the tops of bursting buds, and as 

 they mature the leaves may curl up and protect them and their 

 progeny. As their numbers increase, they pass to the shoots, stopping 

 the growth and causing deformity of the internodes. These apterous 

 females give rise to a winged generation about June and July ; most of 

 these die but some migrate, though to what plant has not yet been 

 ascertained. In America it is believed they fly to plantains. Alate 

 females return to the apple in September to November and produce 

 the apterous egg -laying females and some alate males. This Aphid 

 has been known to ruin the crop completely and cause a serious 

 set back to the trees for the next season or even longer. 



Aphis pomi is found densely packed beneath the leaves or in 

 scattered groups, but the leaves are never curled to the same extent 

 as by A. malifoliae. About June and July this Aphid multiplies 

 very rapidly, the winged individuals, which are found from June 

 to August, migrating to other apple and pear trees. The sexual 

 forms appear in October. 



The young of S. padi are found on the first leaves, alate females 

 appearing about mid-June and migrating to cereals, especially oats, 

 but sometimes also barley, wheat and grasses. In October winged 

 females return to the apple and pear and produce the ovipositing 

 individuals, eggs being laid on the trees as late as November. 



Autumnal spraying to kill the egg-laying insects seems to be the 

 most effective means of eradication ; the spray should be applied 

 heavily, more as a wash, and if possible after rain ; if dusting is resorted 



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