188 Diseases of Truck Crops 



by the wind. But infected manure in the seed bed 

 will result in infected seedlings carrying the disease 

 into a new field. Club root is known to attack a 

 large number of cruciferous hosts, the more suscepti- 

 ble of which include all of the cultivated species. 



Control. The best method of controlling club root 

 is to grow cabbage on new land, or on land that 

 was rotated with other crops, and given a rest from 

 cruciferous crops for some time. Where it is not 

 possible to do this, infected fields should be limed. 

 Table 15, adapted from Cunningham, 1 clearly shows 

 the effect of lime in controlling club root. 



From Table 15, it is seen that the use of fresh or 

 air-slaked lime lowers the percentage of club root as 

 compared with the calcium chloride on check plats. 

 Moreover, when clubbing appeared in the limed 

 areas, the disease seemed to be confined to the lowest 

 roots and outside of the reach of lime. This then 

 enabled the affected plants to make a crop in spite of 

 the disease. The best effect of liming may be ex- 

 pected when the lime is thoroughly incorporated in 

 the soil to a depth of six to nine inches. As far as 

 possible the trucker should avoid susceptible varieties 

 of cabbage, among which may be mentioned : Mam- 

 moth Rock Red, Dark Red Erfurt, American Savoy, 

 Perfection Savoy, All Seasons, and Volga. Of the 

 more resistant varieties of cabbage may be mentioned 

 Hollander, Stone Mason, Large Late Flat Dutch, 

 and Henderson's Early Summer. Finally, care 



1 Cunningham, L. C, Vermont Agr. Expt. Sta. Bui., 185 : 67-96, 

 1914. 



