Distribution and Severity of Alfalfa Pests 



Diseases (continued) 



I I Not known to occur or occurs but is not an 

 important problem 



1 i Occasionally causes significant losses on 

 susceptible cultivars 



k"--i Frequently causes significant losses on 

 susceptible cultivars 



Y/A Figure 19 only: Usually present and causes 

 losses on susceptible cultivars 



Figure 12. — Alfalfa rust, Uromyces striatus Schroet. 



Figure 13. — Sclerotinia crown and stem rot, Sclerotinia 

 trifoliorum Eriks. 



Figure 14. — Spring black stem, Phoma medicaginis Malb. & 

 Roum. (Ascochyta imperfecta). 



Figure 15. — Stemphylium leaf spot, Pleospora herbarum 

 (Pers. ex. Fr.) Rab. (Stemphylium botryosum Wallr.). 



Figure 16. — Summer black stem, Cercospora medicaginis 

 Ell. & Ev. 



16 



