58 BEAN CULTURE 



that any fungicide, good for controlling bacteriosis, 

 will not prove equally effective with anthracnose. 

 He finds that bacteriosis is greatly favored by cer- 

 tain climatic conditions, in fact this much is true of 

 all fungous diseases, and, therefore, no matter what 

 precautions are taken, the disease may be much 

 more abundant some seasons than others. While 

 this in a way would discourage the grower he should 

 double his efforts to bring on a good crop of beans 

 by careful spraying and well directed precautionary 

 methods. 



Mildew (Phytophthora phaseoli), a serious enemy 

 of lima beans, was first described by Thaxter** and 

 later more fully considered by him. *** Halsted**** 

 says a microscopic examination of the plant affected 

 with downy mildew shows that it is penetrated by the 

 slender threads of the fungus which come to the sur- 

 face and there produce tufts of branching filaments 

 and bear multitudes of spores, all of which consti- 

 tute the light moldy covering, which suggests the 

 common name of downy mildew given to many 

 members of this family. Prof. W. C. Sturgis****"^ 

 has made a careful study of the disease; his illustra- 

 tions of the disease are pictured in Fig. 15. 



Treatment. — Bean mildew depends largely on the 

 amount of moisture and will be less noticeable in dry 

 seasons than in wet. This suggests that the grower 

 avoid putting his beans on low ground. Select fields 

 favored with a high and dry location because in such 

 situations the mildew will be much less certain to 

 ^ain a foothold. Conclusions drawn from the exper- 

 iments with fungicides show that even in a season 



•N J Bui 151. "Botanical Gazette, Vol 15. *-Ct Sta Rpt, 1889, 

 ****Ct Sta Rpt, 1897. *****N J Bui 151. 



