52 THE REPORT OP THE No. 38 



until May 25th. The third treatment was made on June 4th. A fourth treat- 

 ment was applied on June 18th, but only to half the acreage. So that, in 

 summary, 25,000 cabbage plants, transplanted about April 25th., received three 

 applications of Mercury Bichloride at 1 oz. to 10 gallons of water on May 11th, 

 May 25th, and June 4th, and about 12,000' plants received a fourth application 

 at the same strength on June 18th. 



The results showed no maggot injury, and no larval infestation was observed 

 on any plants examined either on those plants which had received three applications 

 or those which had received four. The stand was perfect, and the experiment 

 was a complete commercial success. About 1,000 plants died in the first week 

 or two after transplanting, from a damping-off fungus, but these were not 

 replaced. In fact no plants were replaced throughout the season. The crop 

 harvested was 29 tons of marketable cabbages. It may be stated here, that in 

 another block of 25,000 cabbages under similar crop handling and growing on 

 similar soil and presumably with a similar degree of infestation but untreated, 

 the crop harvest was 16 tons. Time did not allow us to check closely the 

 comparative data of fly or larval infestation. Consequently, even allowing for 

 all variations and experimental errors the difference in. the marketable yields 

 was so great as to leave no doubt at all as to the efficacy of the Mercury Bichloride 

 treatment. 



Various blocks of cabbages at various points in the Xorth Okanagan were 

 treated on our recommendations with Mercury Bichloride, under individual 

 growers' own immediate directions. Records from these blocks have now been 

 received, and without exception complete satisfaction has been obtained. Several 

 growers reported no loss at all, others claimed a slight degree of infestation, 

 after the last treatment at the end of May, and all recorded yields per acre of 

 from fifteen to twenty tons. In the Armstrong district, of those cabbage planta- 

 tions which were not treated, not twenty-five per cent made even small cabbages, 

 and in those blocks where the paper discs Were used about seventy five per cent of 

 marketable heads were cut. The results of the 1919 and 1920 experiments 

 have left no doubt in our minds as to the efficacy of the mercury salt treatment, 

 and those growers with whom we have worke/d are clearly of the opinion that 

 the tar paper disc is not so good, and although the cost may be less, the tar paper 

 method is not so commercially practicable as the mercury treatment. 



Method of Application. The method of application we used in handling 

 25,000 plants was as follows : 



A concentrated stock solution was prepared the day previous to treatment 

 by dissolving the mercury salt in boiling water. This was done by suspending 

 the salt in the sugar sack in a fifty American gallon oil barrel, and pouring the 

 boiling water over the sack. This stock solution was drawn on a waggon to the 

 centre of the field, a large watering cart with a capacity of two hundred Imperial 

 gallons and a number of empty barrels being drawn also to the same point. 

 This stock solution was reduced to make a solution of 1 oz. to 10 gallons of 

 water, there being 2 oz. of mercury salts in each gallon of stock solution. Two 

 ordinary four gallon, coal oil tins were suspended on a yoke placed across the 

 labourer's shoulders, and the diluted solution was applied to the roots of each 

 plant, at the rate of two fluid ounces, by means of a cheap dipper. 



