202 Journal of Agricultural Research voi.xv.No.3 



are often so severely attacked that stunting results (PI. 13, B). A few 

 scattered plants in a field or nearly all may be so affected, depending 

 chiefly on the meteorological conditions. Some observations on the 

 extent of the injury by angular-leafspot in a representative locality 

 may here be noted to give a more definite idea of the damage which 

 it causes. At Ripon, Wis., in the summer of 1914, sixteen cucum- 

 ber fields were under observation. The disease appeared in seven 

 of these while the plants were in the seedling stage, and by the middle 

 of the season, August 1 1, it had resulted in the severe spotting of approxi- 

 mately 25 per cent of the leaves. On August 11 the disease was also 

 present in three of the nine other fields, but in these it had been intro- 

 duced only a short time and had not yet become generally distributed. 

 A survey of the same locality on August 15, 191 5, indicates how wide- 

 spread the disease may become, especially when the fields are close 

 together. On that date 28 out of 35 fields visited were found to be 

 infested. A later visit revealed even further distribution. 



The losses in the regions where cucumbers are grown for pickling 

 purposes result mainly from the decrease in yields due to the destruc- 

 tion of leaf surface, but it seems quite probable that in other sections, 

 as has been pointed out by Burger (i, 2) for Florida, where cucumbers 

 are grown for "slicing" purposes, and so must be shipped to distant 

 markets or kept in storage for considerable lengths of time, an addi- 

 tional loss may come from the secondary soft-rotting of the fruit. Lim- 

 ited observations by the writer indicate that in California the soft- 

 rotting of the fruit as an indirect result of the angular-leafspot may 

 cause some loss. The bacterium causing the leafspot does not directly 

 cause the fruitrot, but through the wounds which it makes on the fruit 

 softrot organisms are frequently able to gain entrance. 



The widespread distribution of angular-leafspot and its frequent 

 occurrence give it a place among the major diseases of the cucumber. 

 The aggregate loss which it entails probably exceeds that caused by some 

 of the other diseases which are more destructive in limited areas. In 

 America this disease has been reported from Florida by Burger {1-4), 

 and from Connecticut, Indiana, Michigan, New York, and Wisconsin 

 and the Canadian Provinces of Ontario and Quebec by Smith and Bryan 

 (75). To this list of regions where it is known to occur may now be 

 added California, Colorado, Illinois, Iowa, Minnesota, and Virginia. 

 That it is probably widely distributed in Europe is indicated by the fact 

 that Traverso (16) reported it from Italy, and Potebnia (12) recorded its 

 occurrence in Russia. The wide distribution of the disease is a fact that 

 should be expected in view of the evidence to be presented that the 

 causal bacteria are seed-borne and in view of the general occurrence of 

 the trouble in seed -growing localities. 



