44 



(roration, the falling on them of cold dew. Kiilb) while they are in 

 bloom, or when the berries become hard grains and spoil before they mature. 

 They also become diseased, if they freeze and the blight injures the buds 

 after pruning. Untimely heat has the same results, for everything has its 

 definite measure and goal." At present we summarize the experiences more 

 exactly in our teaching of an optimum and of minimum and maximum limits 

 for the factors of growth. 



In reference to defective cultural methods it is stated that diseases arise 

 when the vine-dresser ties the vines too tightly or injures the roots when 

 digging around them and barks or bruises the trunk. Under all these con- 

 ditions they (the vines) endure wet and cold much less easily because each 

 mjury penetrates into the wound from without. Scarifying is recommended 

 as a remedy because the thickening bark fastens the stems together and plugs 

 them. As a protection against the frosts of winter, is mentioned the method 

 by which water-ditches are dug about the grape vines in winter, when the 

 ground is covered with snow, so that the cold can not blight them. 



The most abundant information as to cultural methods and the evils 

 attendant on them may be found in the collection of excerpts from old agri- 

 cultural authors, which was made in the tenth century, the "Geoponika." 

 We base our discoveries here on the books of the four well-known Roman 

 Geoponicists, Marcus Cato, Terentius \^arro, Palladius and Junius Modera- 

 tus Columella, in which special attention is paid to the practice of fertilization 

 and grafting. A compilation of the books on agriculture by the authors 

 here named appeared in Cologne in 1536'. 



From this work I will choose those places which show that the term 

 "rust" as a cause of disease is of very early origin. Thus Varro mentions 

 in the first chapter, among the gods, "qui maxime agricolarum duces sunt" 

 . . . . "Quarto Robigum, et Floram. quibus propitiis, neque rubigo fru- 

 menta, atque arbores, corrumpit, neque non tempestive florent. Itaque 

 I'Uljlicae Robigo feriae, robigalia, Florae ludi, floralia instituti." The ex- 

 pression "rust" was used probably for all rust colored, diseased discolor- 

 ations in plants, for we find the word Robigo used by Columella to designate 

 a disease of grapes which can be avoided, when frost threatens, by smudging 

 the vineyards. In his book, "de arboribus," Chapter XIII treats of: Ne 

 rubigo vineam vexet. It is recommended "Palearum aceruos inter ordines 

 uerno tempore positos habeto in uinea : cum f rigus centra temporis con- 

 suetudinem ne intellexeris, omneis aceruos incendito, ita fumus nebulam 

 et rubiginem remouebit." The following place is found in the "Enarratio 

 priscarum vocum" in regard to the interchangeable usage of "Robigo" and 

 "Rubigo" ; "Robigo, deus, quern putabant rubiginem auertere, est aute Rubigo 

 morbus segetum"-. 



1 De re rustica M. Catonis liber I., M. Terentii Varronis lib. III., Palladii lib. 

 XIV. et I. M. Columellae lib. XIII. Priscarum vocum in libris de re rustica enar- 

 rationes, per Georgium Alexandrinum. Coloniae, Joannes Gymnicus. Anno 

 MDXXXVI. 



- Here, as in the following- citations, we will follow our sources exactly. 



