Plant-Diseases a?id Insects. 



121 



Mr. Jacquart. Soil clayey ; varieties, Semis de Bevere, Juno 

 and Rouge ; two applications for two varieties, and three 

 for the other. June 30, July 14 and 29 . Gain 7, 000 to 8, 000 kilgr.* per hect. f 



Mr. Brutsaert, of Watou. Soil clayey ; variety, Rykmaker's. 



Late ; three applications, July 14 and 29, August 16 



_ § Gain 10,343 



Mr. Planque, of Wervicq. Soil, sand and clay ; varieties va- 

 rious ; three applications, July 9-12 and 25-28, August 

 18-21. :\ Gain 3,000 to 11,200 



Mr. Knook, of Oud-Vosmeer. Soil clayey; variety, Bleue de 

 Zelande; two applications, July 9 and 18. Gain 8,662 



" In the experiments conducted by the author, the superi- 

 ority of certain treatments was apparent, according to the times 

 when the applications were made. I had two separate fields, 

 one of which was neglected. The first application was made 

 June 23 ; the second was delayed until July 21. Here and 

 there certain pale spots appeared on the foliage, but no atten- 

 tion was paid to them. At the beginning of August the in- 

 jury spread so rapidly that, with the exception of a few squares, 

 a third application was entirely impracticable. The yield 

 of the treated and untreated rows, although considerably dif- 

 ferent, was nevertheless poor. The other part, which was 

 planted with three early but susceptible varieties, was sprayed 

 June 4, 17 and 26, and one are J which was planted with ronn°" 

 Blanche de Schelderode by mistake, was sprayed June 4 and Europe. 

 26, and also July 21. All gave splendid results. The maxi- 

 mum number of diseased tubers was not over two per cent. 



" There can be no doubt that these results are due to the fact 

 that the mixture was applied before the spores of the fungus 

 had germinated, and that the applications were repeated be- 

 fore the fungicide already applied was washed from the foli- 

 age. It is only a preventive method of treatment that gives 

 complete results. This has been proved again and again. 

 The progress of the disease can be checked only by the aid 

 of climatic conditions, for the experiments have shown that 

 late applications were of little practical value. 



"Mr. Proost, the Minister of Agriculture, recommends the 

 use of 4.4 pounds of the sulphate of copper, and 3.3 pounds 

 of lime in preparing the Bordeaux mixture. Several growers 



*A kilogram is 2.2 pounds. 



fA hectare is 2.47 acres. 



tAn are is about one- fortieth of an acre. 



9 



