74 James G. Horsfall 



probably synonymous with K. caulivora. If this should prove to be true, 

 then the name would have to be K. trifolii (Peck) Karak. emend. The 

 writer has not seen Peck's specimen. 



Pathogenicity. The researches of Mehner (1901:195), Fulton (1910), 

 Wellensiek (1926), and Sampson (1928) have shown beyond reasonable 

 doubt that the fungus is pathogenic to clover plants. 



Life history. There has been much controversy regarding the source of 

 inoculum in newly sown fields. The common assumption dating from the 

 paper of Mehner (1901) has been that the fungus is transported with the 

 seed. Fulton (1913:249) says, " The spores when dry retain their vitality 

 for a number of months, and it is likely that such dust-like spores lodged 

 on the outside of seeds may serve to carry infection. Clover trash may 

 harbor the fungus, and serve the same purpose." The point seems still to 

 be in doubt, for Wellensiek (1926:297) says, "As far as exact experiments 

 were undertaken, no carrying by the seed could be observed." Miss 

 Sampson (1928:127) got infected plants by planting inoculated seed in 

 sterile soil under bell jars even though " positive evidence for the trans- 

 mission of the disease by naturally contaminated seed has not been 

 obtained." 



It seems probable from the writer's field observations of anthracnose 

 lesions in the early spring that the fungus overwinters in the perennial 

 green stems. Miss Sampson found a similar condition. Splashing rain 

 undoubtedly is necessary for dislodging the gummy conidia from their 

 acervuli and transporting them to the infection court. 



Conidia germinate very rapidly in distilled water, sending out long germ 

 tubes. Miss Sampson (1928:119) placed conidia on succulent stems and 

 studied penetration by stripping off bits of the epidermis at intervals. 

 The cells are penetrated after the third day, but she did not see the actual 

 penetration tube. She assumes that it passes directly through the cuticle. 

 She says that the first evidence of infection is darkening of the epidermal 

 cell immediately beneath the spore. The protoplasm contracts and 

 becomes discolored. Within a week the dark-brown spots appear on the 

 stems on which spores are produced again. 



According to Wellensiek (1926:296), "Infection is favored by a tem- 

 perature of about 20°C. and by great moisture. Drought, on the other 

 hand, seems to make the plants more susceptible." 



Control 



Many writers, assuming that the organism is carried with the seed, have 

 recommended seed treatment. Baudys (1924) applied 1-per-cent corrosive 

 sublimate for ten to twenty minutes, but the control was unsatisfactory. 

 Fulton (1913:249) recommends the use of seed from anthracnose-free 



