1918.] DISEASES OF PLANTS. 851 



but more particularly iDjurious to M. vallesiaca. The fungus is considered to 

 be closely related to S. panacis and )S. libertiana. 



Wilt diseases of okra and the Verticillivim wilt problem, C. W. Cakpkmek 



{V. S. Dept. Agr., Jour. Agr. Research, 12 (1918), No. 9, pp. 529-.5Jf6, pis. 12). 



The author states that there are two wilt diseases of okra, caused, respectively, 

 by Fusarium vasinfectuiii and T'. alboatrum, which are so similar that they can 

 be differentiated only by isolating the causal fungi. The Fusarium wilt is 

 more serious in the southern portion of the okra-growing district, while the 

 Verticillium wilt is more serious in the northern portion, although the former 

 has been found in Connecticut and the latter in South Carolina and Alabama. 

 It is claimed that cotton may be attacked by both these fungi. V. alhoatruni 

 was isolated also from the discolored vascular system of wilting plants of 

 eggplant, potato, Abutllon, and Xanthium, causing a wilt disease in at least 

 the first two of these. It is also known to cause a wilt disease of snapdragon. 

 Both the fungi are readily cultivated artilicially, suggesting the persistence 

 of both in a saprophytic con'lition in the soil. Control measures suggested 

 include selection of seed from healthy plants only ; disinfection in formalin 

 solution, 1 : 240, for tv.o hours ; and avoidance in planning rotations of all 

 plants known to be susceptible to these fungi. 



Further evidence relative to the varietal resistance of peanuts to Sclero- 

 tium rolfsii, J. A. McClintock {Science, n. ser., Ifi {191S), No. 1203, pp. 12, 

 13). — In continuation of a previous report (E. S. R., 37, p. 49), the author 

 presents additional data regarding the resistance of the variety Virginia 

 Runner to attacks of S. rolfsii. 



Sugar-cane fungi and diseases of Porto Rico, .1. R. Johnston and J. A. 

 Ste\-enson (Jour. Dept. Agr. P. R., 1 (1911), No. 4, pp. 111-264, pJs. IS).— In 

 this report, which is intended to be a complete discussion of the sugar-cane 

 fungi of Porto Rico so far as yet studied and definitely determined, technical 

 descriptions are given of some ftmgus forms with some popular descriptions 

 of diseases and causal organisms. 



It is stated that sugar-cane diseases have been present and serious since 

 1870, and that some now present several difficult problems. Fungi found 

 chiefly on the roots or lower stalk include Marasmius sacchari, Rimantia 

 stellifera, and (Jdontia saccharicola, all of these being more or less concerned 

 in the so-called root disease. The principal stalk diseases include red rot 

 (CoUetotrichum falcaUim), rind disease (Melanconium sacchari), and a new 

 disease (Cytospora sacchari) which seriously threatens certain varieties. 

 A number of leaf diseases are of universal occurrence, though none appear 

 to be seriously injurious. Descriptions are given of red spot of the leaf 

 sheath (Cercospora vagina:;), red rot of the leaf sheath (Sclerotiuin rolfsii), 

 eye spot (Hehninthosporium saccliari), ring spot (Lcptosphwria saccltari), 

 brown leaf spot (Cercospora longipes), red stripe, and wither tip. The only 

 important disease of cane cuttings, which is that due to Thielaviopsis paradoxa, 

 is readily prevented by dipping the seed in Bordeaux mixture. 



A chlorotic disease occurring on the south coast is described in connection 

 with control measures. Yellow stripe occurs in very limited areas. The new 

 disease (as yet uncontrolled), which is characterized by a mottling of the 

 leaves followed by a stalk canker, occurs in the western portion of the island 

 occasioning heavy losses. Injuries due to such agencies as lightning, winds, 

 floods, and drought are also discussed. Certain abnormalities mentioned are 

 regarded as of little importance. 



A bibliography is appended. 



