LUCERNE. 151 



should immediately be cut as short as possible. If under 

 irrigation, flooding is hkcly to produce disease among the larvae. 



Lucerne Leaf Weevil {Phytonomous posticus). — Has 

 caused tremendous damage in the Western States, but so far 

 has not been responsible for any loss in the Union. Cutting 

 as soon as they appear, followed by frequent harrowing, may 

 keep them under control. Close pasturing may also be of 

 assistance. 



Eel-Worm (Tylenchus spp.). — On low-lying damp ground 

 these worms may prove a serious pest. They are detected by 

 a yellowing of the leaves, stunted growth, and a browning of 

 the tap-root immediately below the crown. A change of crop 

 must be resorted to. 



Root-rot (Ozoniiim omnicorum). — Appears on the roots as 

 orange-coloured threads, the diseased plant nearly always 

 dying. The fungus spreads to sun'ounding plants, and eventu- 

 ally a circle of dead plants will be observed. It does not attack 

 monocotyledons; they should, therefore, be irrown in rotations. 



The remaining fungous and bacterial diseases, e.g... Leaf- 

 spot (Pseudopeziza fncdicaginis), Urophlyctis alfalfce, etc., 

 while very common, are not of much known economic import- 

 ance in South Africa. 



REFERENCES: 



^ " Forage Plants and Their Culture." — Piper. 



2 Oklahoma Bulletin 103. 



■■' Ingle's " Agricultural Chemistry." 



* " New Methods of Plant Breeding."— U.S.D. A. Bureau of Plant In- 



dustry, 167. 



* " New Alfalfa Varieties for Pasture." — U.S.D. A., Bureau of Plant 



Industry, 258. 



