Bui. 1029, U. S. Dept. of Agriculture, 



PLATE II. 



Cabbage Black-Leg. Relation of Spread in the Seed Bed to 

 Subsequent Development in the Field. 



These illustrations show the wide difference in destructiveness of the dise;"ise in plantings 

 from the same seed bed made on diflerent dates and in two neighboring fields. The seed was 

 treated by the grower with 1:1,000 mcrciirie chlorid for oO minutes before sowing. When the 

 first planting was made, on .Tune 11, jirarl [rally no black-leg was noted in the seed bed, while 

 on .Inly I, when the second planting was niailc, the disease had become widespread in the bed. 

 Photographed at Racine, Wis., September 27, 191 i), .shorlly before harvest. 



yl.— Planting of .Tune ]!. Of these plants 31 per cent were affected with black-leg, but only i 

 per cent were prevented from heading by the di.sease. (See Table IX, field No. 1.) 



JS.— Planting of .liilv 1 in the foreground. Of these plants 97 per cent were diseased and 60 per 

 cent were proven led from heading by black-leg. The portion of the field in the background 

 is an earher planting from a different seed bed.' (See Table IX, field No. 2.) 



