190 



THE AGRICULTURAL NEWS. 



June 7, 1913. 



FUNGUS NOTES. 



RECENT WORK ON THE PARASITES 



BELONGING TO TME GENUS 



GLOMERELLA. 



Of recent years problems in mycology have been 

 regarded from a much wider point of view than was formerlj- 

 the case. Particularly is this so in respect to that branch 

 of the .subject known as p;irasitology. As an illustra- 

 tion of this new phase, the work of Shaw in India on 

 Khizoctonia may be cited, and as a still later example, may 

 be mentioned the recent work on the parasites of the genus 

 Glomerella, conducted by C. L. Shear and Anna K. Wood of 

 the United ,States Department of Agriculture. A complete 

 account of this latter investigation has just been published as 

 Bulletin No. 2.52 of the Bureau of Plant Industry, and from 

 this interesting and important paper most of the information 

 in the following article has been abstracted. 



The name Glomerella is applied to the ascogenous 

 forms of Gla'Csporium or Colletotrichum — form-genera of the 

 fungi iraperfecti, the parasitic nature of which is well known 

 in the West Indies. The objects of the work under review 

 were to study the production of the ascogenous stages, and 

 to determine the habits and identity of the numerous forms 

 of Glwosporium and Colletotrichum found upon the same 

 hosts, and upon different hosts. The method of study adopted 

 was to observe the behaviour of the ditl'erent forms in the moist 

 chamber and in pure culture, and to carry out a large 

 number of cross inoculation tests to find out whether a so- 

 called species of Glomeralla found on one host, say on the 

 cotton plant, coukl infect another host, say the avocado, on 

 which a supposed different species of Glomerella was regarded 

 a.s being indiviJually parasitic. Apart from its general 

 interest, the economic value of such an investigation is 

 readily apparent. 



With particular reference to the life history of Glom- 

 erella it is important to understand that until recently, the 

 two principal spore forms, conidia and ascospores, have been 

 described and treated as distinct organisms. As is already 

 pointedout, the conidial forms are well known under the name 

 of Glieosjiorium or Colletotiichum. The essential feature of 

 the work under review is that ascospores, conidia and 

 chlamydospores or appressoria (resting spores) are shown to 

 be normal stages in the life-history of the genus. These 

 facts greatly simplify the generic classification of the forms. 



In regard to the thirty-si.\ hosts — of which the names of 

 some are given later — that have hitherto been considered as 

 being attacked by thirty six different species of Glomerella, it 

 has been found that neither morpholcjgical nor physiological 

 differences can be observed which are sufliciently constant to 

 be regarded as specific characters. All the diflerent forms 

 have been referred by the authors to three species of 

 Glomerella: G. cinyulalu which occurs on thirty-four of the 

 hosts, <1. (jussyjiii on one (namely, cotton), and G. linde- 

 mnthiniiuni, on one. 



G. cinyulata is exceedingly variable in all its characters. 

 The cause of this variability is not yet clear. The essential 

 point about this fungus is that it can often be found to grow 

 from apparently healthy tissue, which has been washed in 

 corrosive sublimate. The explanation is that the chlamydos- 

 pores .send a germ tube down through the epidermis of the 

 host plant, which lies quiescent until the plant becomes weak- 

 ened from some physiological cause, when the fungus begins 

 to develop as a vigorous parasite. 



It i.s stated by the authors: 'Inoculation experiments with 

 fruits have shown that most of the forms from different hosts 

 will produce the characteristic Glomerella rot on fruits of 

 other hosts. It is also shown that there is a great variability 

 in the virility of different races or strains of the fungus from 

 the same host. In one experiment races from the lemon, 

 grape and fig produced more serious cases of bitter-rot of apple 

 than a race nf the fungus derived from apples. These facts 

 are of great importance in connexion with the selection and 

 production of d' -ease- resistant varieties of plants.' 



It may be added, further, that this is cf immense impor- 

 tance in regard to mycologicil legislation, in view of the fact 

 that the disease can apparently spread as easily from temper- 

 ate countries to the Tropics, as within the Tropics itself It 

 must also be remembered that G. cinjulata can also be cirried 

 by any one of thirty-four different species of agricultural 

 plants, includinsr such diverse forms as palms, oranges, apples, 

 gooseberries, cacao and arrowroot. Of great economic signifi- 

 cance is the fact that one species of Glomerella is confined to 

 cotton This species, it may be added, occurs in the West 

 Indies and causes the well-known disease, anthracnose. 



The production or non-production of the perithecial stage 

 of Glomerella appears to be a fairly well-marked hereditary 

 race character. There is no evidence to show that the 

 production of perithecia is controlled by any of the ordinary 

 conditions of nutriment or environment, tliough accurate 

 investigation along this line would possibly lead to results of 

 great importance 



In conclusion, the methods of controlling Glomerella 

 may be briefly summarized as follows: (1) spraying with 

 Bordeaux mixture; (2) selection of fungus free seed— particu- 

 larly valuable in the case of cotton; (3) eradication and 

 destruction of dead and diseased parts of infected pbints. 



The selection and breeding of resistant varieties may 

 also be practicable in some cases. 



ANNUAL REPORT ON THE ROTHAMSTED 

 EXPERIMENTAL STATION, 1912. 



In the introduction to this [jublication, compiled by 

 Dr. E. J. Russell, Director of the Station, mention is made 

 first of the fact that the Rothamsted Experiment Staiion 

 was established in 1813 by the late Sir John Bennett 

 Lawes. The institution has never been connected with 

 any external organization, and it has until recently been 

 maintained entirely at the cost of its founder. By the 

 provision of the Trust Deeds, the management is entrusted 

 to a Committee nominated by the Royal Society, the 

 Royal Agricultural Society, and the Chemical and 

 Linnean Societies and the owner of Rothamsted. During 

 recent years several grants have been made from various 

 sources including the grant of £1,000 by Mr. J. F. 

 Mason, M.P, for the building and equipment of a bacterio- 

 logical laboratory; £10,000 given by the (ioldsmith Co., the 

 income of which is to be devoted exclusively to the investi- 

 gation of the soil: by the Permanent Nitrate Couimittee, 

 a grant of £2,000 has been made. Finally, after several 

 further contributions from private sources, the flovernment 

 has contributed an annual grant of £2,500, and a further 

 grant of £3,000 from the Development Fund for the purpose 

 of extending the Rothamsted plot experiments. 



The Rothamsted Experiment Station is recognized as 

 the institute, in Great Britain, for dealing especially with 

 soil and plant nutrition i)roblems. SchoUrshipn have 

 recently been instituted to provide the training and research 

 work unobtainable at the Universities, and advantage is 

 frequently taken of Rothamsted by investigators from other 



