DISEASES OF PLANTS. 353 



the wounded surfaces develop a callous tissue in wbich may be differentiated 

 the cambium and vascular elements which grow in relation to the corresponding 

 portions of the roots. The tumors require much nutriment, thus hindering the 

 growth of the plant, while these portions, containing little sugar, are either of 

 little or no value or of positive disadvantage to the crop. 



Melon or cucumber canker, T. H. Middleton (Bd. Agr. and Fisheries 

 {London], Ann. Rpt. Intel. Dlv. 1910-11, pt. 2, pp. 5Jt-56). — The canker of melons 

 and cucumbers, due to Mycosphcerella citrulUna, has become quite serious in 

 greenhouses in England, although the disease does not appear to attack out- 

 door plants to any particular extent. The results of the investigations thus far 

 conducted on the siiread of the disease and the means for its control have been 

 very unsatisfactory, and, according to the author, these points require addi- 

 tional investigation. There seems to be evidence that the fungus gains entrance 

 to plants through wounds, and one of the worst cases reported occurred on 

 plants that had been topped. In other cases the infection seemed to follow 

 insect punctures. 



It is believed that thorough disinfection of houses in winter and spraying 

 with Bordeaux mixture might prove efScient in controlling the trouble. 



Collar blight and other collar and root diseases of the apple, M. B. Waite 

 (Rpt. W. Va. Bd. Agr., 1912, No. 25, pp. G6-~'i). — The author discusses a form 

 of pear blight attacking the apple at the thickened portion of the tree just above 

 and below the gi-ound line. For this form of the disease the name collar blight 

 is given. Methods for the control of the disease are described and attention 

 called to some other diseases resembling this trouble in some respects. One of 

 the most common forms of the disease is due to winter injury, which favors 

 the attack of wood rot fungi and hastens the death of the tree. 



Brief notes are also given on the crown gall, woolly aphis, and the fungus 

 root rot. 



Pear blight control, E. A. Gammon {Mo. Bui. Com. Hort. Cal., 1 {1912), No. 2, 

 pp. 37-^1, f>g>i. 3). — The results of 7 years' active effort in the control of pear 

 blight in a large orchard in California are given. They indicate the necessity 

 of careful pruning and thorough disinfection. 



American g'ooseberry mildew, T. H. jMiddleton {Bd, Agr. and Fisheries 

 [London], Ann. Rpt. Intel. Div. 1910-11, pt. 2, pp. Jt-21, m^aps 6). — The present 

 status of the American gooseberry mildew in Great Britain is discussed. The 

 author states that .while this disease is prevalent in certain places in which 

 gooseberry growing is carried on as a commercial industry and has caused seri- 

 ous damage in limited areas, it has not yet spread over the whole kingdom or 

 caused great loss. It is claimed that it may be held in check if proper precaii- 

 tions, such as prompt measures in pruning and spraying, be taken by owners of 

 gooseberry bushes. 



Attention is called to the apparent periodicity of the disease In some locali- 

 ties, a severe epidemic one year being followed by a year with little of the 

 disease. This is attributed to the fact that the resting spores of the fungus 

 possibly fail to germinate and carry over to a second season. 



The rusts of wild grapes in India, E. J. Butler {Ann. Mycol., 10 {1912), 

 No. 2, i)p. 153-158, fig. 1). — Two species of rusts, said to occur on wild grapes 

 in India, are discussed. One is said to agree closely in description with the 

 previousl-y known Phacopsora vitis; the other, claimed to be new, is described 

 under the name Ghrysomyxa vitis. The first is deemed a very active parasite 

 and a possible source of danger to cultivated vines. 



A coconut disease of Mexico, R. Olsson-Seffeb {Rev. Trop. Agr., 2 {1912), 

 No. 4, PP- 295, 296). — Attention is called to a bud rot disease due to a fungus, 

 said to be PytMum palrnivorum, which kills the coconut trees in patches of 3 



