203 



Alfalfa 



Leaf Spot 

 Caused by Psciidopccica iiicdicagi)iis (Lib.) Sacc. 



This disease is the only important alfalfa disease occurring in Illi- 

 nois. The first report of its presence in the state was made by Burrill 

 in 1912. when it was found in Champaign. Edgar, and Union counties. 

 Anderson reported it in Tazewell and Champaign counties in 1919. It 

 is now known to occur in (u counties widely distributed throughout the 

 state, as shown on I\Iap 34, but appears to be more general northward. 



Plants infected with this disease lose their vigor, and a loss in hay 

 through falling of the diseased leaves also occurs. Generally not more 

 than one of a season's cuttings (usually the second) is seriously diseased, 

 but the effect on that cutting may be very severe. An examination in 

 1922 of 61 fields distributed among 158 rejiresentative counties and in- 

 cluding 3-49 acres indicated that 66.6 per cent of the plants were diseased 

 and that 7.64 per cent of the leaves were spotted. Similar examinations 

 made in 1923 in 36 fields distributed among 20 counties and including 

 261 acres indicated that 77.5 per cent of the plants were diseased and 

 3.85 per cent of the leaves spotted. 



As a means of control, it is best to cut the infected crop as soon as 

 it becomes apparent that the result of the infection is a]3t to be severe. 

 If this is done the succeeding crop will usually be relatively free from 

 the disease. 



Rust 

 Caused by Uroniyccs slrialiis .Schr. 



This disease is said to be responsible for local losses in neighlioring 

 states. In Illinois it has been found in two counties, Edgar and Wood- 

 ford. In neither case was the infection either abundant or severe. 



Anthracnose 



Caused by Collctotr'ichuin trifolii Bain 

 This disease has been found in two counties, Putnam and Henry, 

 biU is not known to be of common occurrence or of a serious nature in 

 our state. 



Root-and-Crown-kot 

 Caused by Fusarium sp. 



During three seasons past there have been incidental reports of a 

 root-and-crown-rot of alfalfa apparently due to the attack of a species 

 of Fusarium. The first instance of this was from Randolph county, and 

 later reports and specimens have been received from Carroll county. 



