abstracts: phytopathology 195 



In most of the forms studied neither morphological nor physiological 

 conditions sufficient for the segregation of species have been found, but 

 three species are recognized from the 36 hosts. Glomerella cingulata 

 (Stonem.) S. & v.S. found on 34 hosts, the type on Ligustrum vulgare. 

 G. gossypii Edge, on one host, Gossypium hirsutum (cotton) and G. 

 lindemuthianum Shear on Phaseolus vulgaris (wax bean). 



Glomerella cingulata is exceedingly variable in all its morphological 

 characters. The cause of this variability is not clear. No constant or 

 definite relation has been established between the environmental con- 

 ditions and the most important variations observed. The fungus is 

 found to be present in many cases on apparently normal healthy fohage 

 fruits, and sometimes stems, as shown by its development and fructifica- 

 tion on these plant parts after their surfaces have been thoroughly steri- 

 lized by washing with an antiseptic solution which has been shown to 

 kill not only ascospores and conidia, but also chlamydospores or appres- 

 soria of the fungus. Germ tubes appear to penetrate the epidermis and 

 then remain in a quiescent condition until circumstances favorable for 

 further development occur. 



Inoculation experiments with fruits show that most of the forms from 

 different hosts will produce the characteristic bitter-rot or anthracnose 

 of fruits of other hosts. Practically the same degree of variability is 

 found in the virility of races or strains of the fungus from the same host 

 as from different hosts. 



The production or non-production of the perithecial stage of Glo- 

 merella appears to be a fairly well-fixed hereditary race character. 

 The organisms of this genus have developed special features, the most 

 important of which are its method of infection by means of appressoria, 

 and its ability to live in a dormant or inactive condition in the tissues of 

 the host until some specially favorable conditions for its further develop- 

 ment occur. In many cases the fungus never develops further until the 

 infected part of the host dies. The fungus also develops in seeds of cotton 

 and bean especially and thus insures its passing the winter and reaching 

 the new crop. 



It has been shown by experimenters that diseases af apples and citrus 

 fruits caused by this fungus can be satisfactorily controlled by spraying 

 with Bordeaux mixture, and it is probable that this method can be suc- 

 cessfully used in prevention of diseases of other plants caused by the same 

 fungus. The selection and breeding of resistant varieties may also prove 

 practical in some cases. ' C. L. S. 



