Plant Sanitation. 



138 



(August, 1908. 



or fruit. The first work was done in 

 1901, at the suggestion of Mr. M. B. 

 Waite, and consisted of experiments 

 with various sulphides, all of which 

 proved injurious to peach foliage. Dur- 

 ing the season of 1907 self-boiled lime- 

 sulphur mixtures in various proportions 

 and strengths were tested on both the 

 apple and the peach. 



Preparation of the Mixture. 



The mixture that gave the most pro- 

 mising results was composed of 10 lbs. of 

 sulphur (flowers or flour) and 15 lbs. of 

 fresh stone lime to 50-gallons of water, 

 and may be prepared as follows :— 



Place the lime in a 50-gallon barrel and 

 pour a 2 or 3-gallon bucket of boiling 

 water over it. Immediately add the 

 sulphur and another bucket of hot 

 water. The heat from the slaking lime 

 will boil the mixture violently for 

 several minutes. Some stirring is neces- 

 sary to prevent burning, and more water 

 should be added if the mass gets too 

 thick to stir, but the cooking is more 

 effectual when the minimum quantity 

 of water is used, usually from 6 to 8 

 gallons being required. A piece of old 

 carpet or gunny sack thrown over the 

 top of the barrel helps to keep in the 

 heat. The boiling will continue from 

 twenty to thirty minutes, depending 

 upon the quality of the lime. When the 

 boiling ceases, dilute with cold water to 

 make 50 gallons, stir thoroughly and 

 strain through a seive of about 20 meshes 

 totheinchin order to take out coarse 

 particles of lime, but all the sulphur 

 should be carefully worked through. 



In a similar manner, enough for 150 

 gallons may be prepared in a barrel by 

 using 30 pounds of sulphur and 45 pounds 

 of quicklime, with about 20 gallons of 

 boiling water. When the boiling ceases, 

 the barrel should be filled with cold water 

 and diluted with 100 gallons more when 

 transferred to the spray tank. 



In some of the experiments awash con- 

 sisting 5 pounds of sulphur and 10 pounds 

 of lime to 50 gallons of water gave 

 excellent results. This would indicate 

 that a much more dilute mixture than 

 the 10-15-50 formula may prove to be 

 a satisfactory fungicide. The wash was 

 also prepared with cold water instead 

 of boiling water, and in some cases a por- 

 tion of the lime was at first withheld 

 and later added, a small lump at a time, 

 in order to prolong the boiling ; but the 

 experiments have not yet been sufficient 

 to determine definitely the correct for- 

 mula and the best method of prepar- 

 ation. 



$ Should the boiling be very prolonged 

 £he mixture might become caustic enough 1 



to burn foliage, although no such injury 

 developed in the experiments. If it 

 should be found in practice that the 

 use of hot water dissolves too much 

 sulphur, so that the foliage is uninjured, 

 cold water may be substituted and a 

 less intense heat thus developed, or the 

 sulphur can be withheld until the lime 

 has partly slaked, thus regulafcinar the 

 amount of sulphur dissolved. 



By this boiling process the sulphur 

 is put in good mechanical condition for 

 spraying, and enough of it is dissolved 

 to make the mixture adhesive. As a large 

 percentage of the sulphur is simply held 

 in mechanical mixture with the lime 

 water, it is necessary that the spraying 

 outfit be provided with a good agitator, 

 so that the mixture may be kept con- 

 stantly stirred, and settling be thus 

 avoided. In the treatment of apple 

 trees, Paris green may be added for the 

 control of the codling moth in the same 

 manner as when Bordeaux mixture is 

 used. 



Although bitter-rot was severe enough 

 on the apple trees to destroy from 80 

 to 90 per cent, of the crop on the 

 unsprayed trees, the lime-sulphur mix- 

 ture held it down to less than 10 per 

 cent, of the crop. In this experiment the 

 sulphur wash compared favourably with 

 Bordeaux mixture, the latter giving 

 only slightly better results. The disease 

 had a considerable start before the first 

 application was made, and this accounts 

 for at least a part of the diseased 

 fruit on the sprayed trees. Slightly 

 better results with both the sulphur 

 and the copper treatments could prob- 

 ably have been secured had the first 

 application been made a week earlier. 



It would appear that the two fungi- 

 cides are equally effective against bitter- 

 rot, and that when desired the lime- 

 sulphur mixture may be substituted 

 for Bordeaux mixture in the treat- 

 ment of this disease. These results 

 show that the self-boiled lime-sulphur 

 mixture is an excellent fungicide under 

 the conditions attending this experi- 

 ment. The only question that remains 

 is whether it will maintain this high 

 standard under unfavourable condi- 

 tions, such as extremely wet weather. 



So far as the writer could observe, 

 absolutely no injury to the fruit or 

 foliage developed from the use of this 

 wash, and it adhered almost, it not 

 quite, as well as Bordeaux mixture. At 

 picking time the foliage was still white 

 with the mixture and the fruit had a 

 good coat of it. Again, however, it 

 must be remembered that the season 

 was comparatively dry, the rainfall for 



