84 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Pathogenic Fungus.* — H. Windsor Wade has studied in Manila a 

 new type of fungus, causing a peculiar chronic skin infection. Cultures 

 were made, and in time the mycelial form of the fungus was obtained. 

 Various growth-phases were observed that are not generally recognized 

 as occurring among fungi, but it is believed that under certain con- 

 ditions fungi might revert to these forms — gelatinous and vescicular- 

 body formations, etc. The classification and name of the new fungus 

 are left in abeyance to await the results of further study. 



Tuber-rots caused by Fusarium.t — C. W. Carpenter has devoted 

 much attention to this subject, with regard to the rotting of potatoes. 

 He describes his method of testing parasitism, and gives a general 

 account of the various strains, with descriptions of the different species. 

 In his summary he notes a new species, Fusarium eumartii, which causes 

 stem-end and wound-invading dry-rot, a wide-spread disease in Penn- 

 sylvania. It is similar in action to F. radicicoJa. The latter, associated 

 with F. oxysporum, gives rise to jelly-end rot, " a serious trouble in the 

 tule lands of California." F. oxysporum and F. hyper oxysporum may 

 entirely destroy potato-tubers. 



Immunity from Parasitic Fungi.l — B. C. Stakman, following in 

 the lines of previous workers, has made a study of infection by Puccinia 

 graminis. He found that the host-plant in many instances is hyper- 

 sensitive to the fungus, the cells being killed .by the invasion, and the 

 further progress of the true parasite being prevented. He carried out 

 a large series of inoculations of P. graminis from one host to another, 

 from oats to rye, oats to barley, etc. In almost every case the parasite 

 succumbed. He found that ithe germ-tubes gained entrance, but that 

 the cells very soon became disintegrated, their death promptly following 

 the invasion by thehyphte. The death of the hyphfe themselves follows 

 sooner or later, probably from lack of the nourishment required by the 

 parasite, or from some definite antagonism between the host and the 

 parasite which requires further explanation. 



Plant Diseases. § — A report on wart-disease of potatoes as regards 

 the immunity of certain varieties is now published. The immunity 

 trials were carried on at Ormskirk during the years 1915-1917. It 

 had been already proved that any fungicide, such as lime, sulphur, 

 formalin, etc., to be of service had to be employed in such strength that 

 the potato-plants themselves were killed. Immunity is an inherent 

 quality of the variety, and is not affected by outward conditions, and it 

 has becu proved that such variety retains its immunity an indefinite 

 number of years. Reports have been received to the contrary, but 

 investigation has always shown that the diseased plants were " rogues " 

 of susceptible varieties present amongst the crop. A detailed account 

 is given of various plantings, and the results are carefully tabulated, so 



* Philippine Journ. Sci., xi. (1916) pp. 267-83 (5 pis.). 



t Journ. Agric. Research, v. (1915) pp. 183-209 (4 col. and 6 photo, pis.). 



X Journ. Agric. Research, iv. (1915) pp. 193-9, 



§ Journ. Board Agric, xxiv. (1917) pp. 801-18. 



