70 



THE MONTHLY BULLETIN. 



The Gopher (Thomomys sps.) 



These rodents are often very destructive to alfalfa. They may be 

 drowned out where irrigation is practiced, may be trapped or poisoned 

 by the use of raisins with a little strychnine inserted in a slit made m 

 the raisin, and all placed in their runways. 



FUNGI. 



The following rather formidable list of fungi attacks alfalfa; the 

 first four menace the crop in California: 



1. Pseudomonas medicagims. 



2. Crown gall {Urophhjctis alfalfce). 



3. Leaf spot {Fseudopeziza medicaginis) . 

 Rust (JJromyces striatus). 

 Wilt, or stem rot {Sclerotinia lihertiana). 

 Anthracnose (Colletotrichum trifoln). 

 Root rot {Ehizoctonia violacce). 



8. Downy mildew {Peronospora trifolium). 



9. Leaf spot {Ascochyta sp.). 



10. Brown root rot {Ozoniuni auricomum). 



11. Leaf spot {Cercospora medicaginis). 



12. Seed disease {Alternaria sp.). 



13. Damping off fungus {Pythium de haryamim). 



4. 

 5. 

 6. 



7. 



Fig. 16. — The alfalfa weevil. Adults cluster- 

 ing on and attacking the stems and leaves of 

 alfalfa. (After Webster.) 



Our knowledge of these often invisible intruders is all too limited, 

 but it is rapidly increasing, and we need not be nervous. The fungi 

 send minute threads, hvphae, into the plant tissue and bring disease, 

 often death. The mass, or tangle, of liyphte forms the mycelium. A 



