86 SUAI.MAllY OF CURRENT RESEARCHES RELATING TO 



and inoculation experiments were successfully carried out. The writer 

 finds that the fungus is "low in parasitism, and that conditions of 

 moisture are important factors in its development." 



A. H. Gilbert and C. W. Bennet * have made a descriptive and 

 cultural study of Scierotinia Trifoliorum, the cause of stem-disease in 

 Clovers ; it causes the wilting of the leaves and the final destruction of 

 the clover crop. Sclerotia are formed in spring and germinate in 

 autumn, to form apothecia. The ascospores from this form hyph^,. 

 which live in the soil and attack the clover-plants in spring. Rotation 

 of crops is the cure most frequently recommended. Deep ploughing 

 and liming of the soil have also had good results. It is not ye"t 

 known whether, or how long, the mycelium can live in the soil on other 

 plants than alfalfa. 



B. Peyronel f records the presence of SpondyloclacUum atrovirens, a 

 Hyphomycete parasite on potato-tubers in Italy. It is of very wide- 

 spread occurrence, but its pathogenic importance is limited. It invades 

 the corky cells of the outer periderm of the potato, but it does not reach 

 the inner starch-layers. 



J. R. Weir J has confirmed the finding of Sturgis that HerpotricMa 

 nigra and Neopeckia Coulteri are not allied. The latter always attacks 

 Pines ; the former grows on other Conifers. The fungi differ not only 

 morphologically, but in their effect on the host -plants. Weir describes 

 another fungus, Herpotrkhia quinqiiesejjtata sp. n., which attacks Picea 

 Engelmamii. 



W. 0, Glover § describes a disease of Clematis causing stem-rot 

 and leaf-spot as due to Ascochyta demaUdina. The plants are killed by 

 the growth of the fungus down the petiole into the stems, thus girdling 

 the plants at the node. The development of the fungus is given in detail^ 

 and means of cure suggested. 



The only known parasitic fungus of leafless mistletoes, Wallrothiella 

 Arcentholii, has been described" by J. R. Weir.|| It is of common 

 occurrence in Montana and Idaho on the false mistletoes of Conifers, 

 and is of economic value in affecting the control of the mistletoes. 

 It is a Pyrenomycete, the spores of which are globose, thick- walled, and 

 hyaline at first, but become brown-black. An account is given of the 

 ecology of the fungus and the conditions influencing its development. 



H. A. Edison 11 has found that four different fungi cause damping- 

 off of seedlings of sugar-beet in America ; these are Phoma Betse, 

 Rhizoctonia sp., Pythium Debaryanum, and a member of the Sapro- 

 legniaces. The latter has not been identified, but it is not Aphanomyces 

 Isevis, which has caused damping-off in other localities. 



A study oi^ Phoma Betse was made by V. W. Pool and M. B. McKay.** 

 It forms light brown spots on the leaves. An account is given of its 



* Phytopathology, vii. (1917) pp. 432-42 (5 figs.). 



+ Rend. R. Accad. Lincei Rome, xxvi. (1917) pp. 509-12. See also Bull. Agric. 

 Intell. Rome, viii. (1917) p. 1320. 



X Journ. Agric. Research, 



iv. (1915) pp. 251-3. 



§ Journ. Agric. Research, iv. (1915) pp. 331-42 (5 pis.). 

 II Journ. Agric. Research, iv. (1915) pp. 359-78 (2 pis.). 

 H Journ. Agric. Research, iv. (1915) pp. 135-68 (10 pis.). 

 ** Journ. Agric. Research, iv. (1915) pp. 169-77 (1 pL). 



