An investigation of some tomato diseases

Abstract

Various of tomato fruits and certain diseases of the stems of tomato plants have been investigated. These fruit rots commonly occur both on imported and upon home-grown fruit and are caused by several different fungi about the identity of which there has been much uncertainty. The fungi isolated from rotten tomatoes have been compared with authentic cultures of certain presumably identical or closely related fungi from the United States. One of the rots is caused by Phoma destructiva, the British form of which is identical with that from America. Another of these rots is produced by a fungus which has hitherto passed in this country under the name of Mycosphaerella citrullina, but which is certainly not identical with the American fungus of that name. The British fungus which has hitherto been mistaken for this and which causes tomato stem “canker” as well as a fruit rot, appears to be identical with Diplodina Lycopersici Hollós which name also replaces Phoma Lycopersici Cooke. It has been considered advisable to amplify Hollós' description and the fungus is therefore named Diplodina Lycopersici (Cooke) Hollós, emend. Brooks and Searle. Another pycnidial fungus, found only once as the cause of a tomato rot is associated with an Alternaria stage, and the name proposed for this fungus is Phoma alternariaceum Brooks and Searle. Finally, various strains of Gloeosporium and Colletotrichum parasitic on tomatoes have been isolated. One of these fungi Is identical with the American Colletotrichum phomoides (Sacc.) Chester, and probably all of these forms are thus best grouped. The desirability of undertaking cultural studies of fungi belonging to such genera as Phoma, Diplodina, and Colletotrichum as an aid in the diagnosis of species, is emphasized.