392 Journal of the Department of Agriculture. 



Cyanide Gas Remedy for Scale Insects. 



Tile citrus iiulustry is rapidly growing in the Union and an 

 important point for consideration in all large commercial plantings 

 of citrus trees, is tlie suppression of Red Scale and other "hard" 

 scale insects which are found in our citrus orchards. The matter has 

 received much attention from the Division of Entomology, and we 

 publish in this number an article by Mr. Louusbury, the Chief of the 

 Division, Avhich gives concise directions for applying the treatment. 

 Mr. Louusbury states that fumigation Avith hydrocyanic acid gas is 

 by far the most efficient and, in the end, the cheapest remedy, and it 

 was through his efforts that it was employed as far back as twenty-five 

 years ago in the Cape Colony. In recent years great difficulty has 

 been met in obtaining the supplies for the treatment, and the remedy 

 has f illen somewhat into disuse. Cloth for making covers for the 

 trees has risen very considerably in cost and so has the price of 

 cyanide, while suitable vessels for generating the gas, once quite 

 cheap and easily obtainable, would now be unprocurable but for the 

 efforts of the Division, which has been able to arrange for their 

 manufacture in this country. Its attempts to interest leading manu- 

 facturers of chemicals, however, in the production and sale of the 

 fumigation poison in liquid form, has not been equally successful. 

 This is unfortunate, for it is highly desirable that the old, crude, and 

 objectionable system of generating the gas in a pot placed beneath the 

 tree to be treated, should be done away with. California has advanced 

 far beyond that system, the gas now being secured by spraying a 

 proper volume of the poison in liquid form under the cover where the 

 liquid at once volatilizes. To Mr. C. W. Mally, our Cape Ento- 

 mologist, is due the idea of employing it and the first practical 

 demonstrations of its utility. But conditions in South Africa 

 precluded the easj;- commercial development of the idea, and the onset 

 of the war brought the matter to a standstill, great difficulty being 

 experienced in importing the necessary apparatus. Though the 

 country generally is not ready for this improved method of treatment, 

 it is well that prospective fumigators should know about it, in order 

 that they may consider its applicability to their individual conditions, 

 and Mr. Louusbury gives details thereof in his article. It is, liowever, 

 to show how best tlie methods now in vogue in the Union are to be 

 cariied out that Mr. Louusbury has written the article, which is help- 

 fully illustrated, and the advice he gives, the outcome of much 

 personal thought and piactical experience, should receive the careful 

 consideration of all those who are building up an industry likely to 

 prove a big asset to the Union, the export of citrus fruit. 



Maize Growers' Conference at Potchefstroom. 



Maize, the staple croj) of i\nt Union, has its own problems, both 

 of a cultural and economic nature, which are engaging the close 

 attention of farmers, scientists, and others connected with the 

 industry. With a view to conferring on several matters of importance 

 to maize growers. Mi'. Reinecke, the Principal of the Potchefstroom 

 School of Agriculture, arranged a conference of farmers, merchants, 

 and others concerned, which met at Potchefstroom on the 6th April 

 last. That the Principal's object was achieved there can be no doubt, 

 and those who were able to attend, some sixty visitors, were 



