10 



MASS. EXPERIMENT STATION BULLETIN 248 



of the leaflets were made to determine the relative merits of the fungicides 

 considered. Only foliage present on the plants at the time of the treatments 

 was considered in the counts. 



When the fungus was applied in water (Table 4), the stronger Bordeaux 

 mixtures furnished better control than the weaker, and the same was true of 

 copper sulfate sprays. Copper-lime dusts proved efficient. Hammond's Slug 

 Shot gave favorable control. Sulfur dusting materials were of no merit, but 

 vaporized sulfur was effective. Lime-sulfur in 1-50 and 1-100 dilutions gave 

 excellent control but also injury. Semesan .25 per cent was inferior to 

 Uspulun .25 per cent. The difference is apparently due to the filler in Uspu- 

 lun. When the plants were inoculated with dry spores (Table 4), only 

 vaporized sulfur and Grape Dust gave significant control. 



Table 4. Comparative Merits of Fungicides in Preventing Infection of 

 Potted Tomato Plants. 



Fungicide 



Check 



Anchor Brand Sulfur Dutt 



Grape Dust 



Schloesing's Sulfur 



Hammond's Slug Shot 



Trick Sulfur 



Vaporized Sulfur 



H. & H. Colloidal Sulfur 



Lime-Sulfur .2% 



Lime-Sulfur .8% 



Lime-Sulfur 1.% 



Potassium Sulfide .08% 



Schacht's Naphtal-Schwefel . . . 

 Sulfur-Lime-Naphthalene 1-1-1 



Sulfuric Acid .05% 



Sulfuric Acid .04% 



Copper Sulfate .06% 



Copper Sulfate .05% 



Copper Sulfate .04% 



Bordeaux 1-1-50 



Bordeaux 4-1-50 , 



Bordeaux 6-6-50 



Copper-Lime Dust 10-90 



Copper-Lime Dust 20-80 



Copper-Lime Dust 50-50 



Niagara D-25 Copper Dust. . . . 



Semesan .25% 



Uspulun .25% 



Uspulun .1% 



Spores Applied in Water 



Leaflets 

 Counted 



100 



108 



100 



119 



90 



S3 



93 



95 



81 



79 



94 



98 

 87 

 95 

 97 



82 



86 



101 

 106 



Leaflets 

 Diseased 



per cent 

 67.0 

 SS.J, 

 19.0 

 46. z 

 10.0 

 22.8 



22.1 

 0.0 



7.5 



6.6 



17.0 



47.9 



13.6 



5.2 



1.0 



16.8 

 4.7 



Spores Applied Dry 



Leaflets 

 Counted 



183 



99 

 141 

 131 

 127 

 123 

 144 



140 



Leaflets 

 Diseased 



per cent 



86.2 



6.0 



65.3 

 62.5 

 33.0 

 7.S 

 38.1 



85.0 



In a further experiment, plants were dusted in upright and inverted posi- 

 tions. When plants were inoculated with spores in water (Table 5) the best 

 control was obtained with Grape Dust, copper-lime dust, vaporized sulfur, 

 and Uspulun. When they were inoculated with dry spores (Table 5) sig- 

 nificant control was obtained only with vaporized sulfur. 



