VAN BREDA DE HAAN'S WILT OF PEANUT. 



In December 1905, J. van Breda de Haan prepared a paper (Teysmannia, 1906) con- 

 cerning a bacterial disease of the peanut Arachis hypogwa, known as "hamawedang,"and 

 observed by him in October of that year in the departments of Koeningan and Cheribon, 

 Cheribon Residency, Java. The following is an abstract of this paper: 



The soil in this portion of Java is chiefly red or red brown, sometimes black-sandy, 

 very porous, and occasionally clayey. Often the stiff clay cracks 

 open in times of drouth. Irrigation is largely practiced and rotation 

 of crops, c. g., sugar-cane is planted for cuttings every third year, 

 then katjang tolok (Phascolus radiatus), after which the peanut 

 (katjang soeoek, katjang holle) is planted, followed by rice. Much 

 care is usually given to the culture of katjang soeoek, low beds of 

 about a yard wide by 4 yards in length with shallow channels be- 

 tween them being used for this purpose. The channels render irriga- 

 tion easy and also allow 

 of thorough drainage 

 and easy access to the 

 plots for weeding, etc. 

 The fields are irrigated 

 every week or less often. 

 There is no trouble any- 

 where from ground- 

 water. 



The variety of 

 Arachis hypogaa used 

 chiefly is the katjang 

 holle or Bandoeng, 

 which ripens in about 

 3 months from date of 

 planting. It is planted 

 chiefly in the East 

 Monsoon in fields that 

 can be irrigated. The 

 product is sold to Chi- 

 nese merchants, who in 

 recent years have paid 



Fig. 68.' 



F.g. 69. f 



good prices for it, making it a very profitable crop, which accounts for its wide cultiva- 

 tion ; and in view of this fact it can readily be seen how a disease which formerly scarcely 

 drew attention should now be considered a serious problem, especially because the yield of 

 katjang holle has noticeably decreased, being sometimes but half a normal crop. Insect 

 injuries were not numerous in the fields examined by van Breda de Haan, and the only 

 fungus disease mentioned is a black spotting due to Scptoglwum arachidis Raciborsky, which 

 is said to have no connection whatever with this disease. 



*Fig. 68. Bacterial disease of peanut (Arachis) from Java: Cross-section of root, showing bacteria confined to 

 the vascular bundles (the heavily inked portions). 



fFic. 69. Bacterial disease of peanut (Arachis) from Java: Cross-section of stem from epidermis to pith, show- 

 ing the bacteria restricted to the xylem (heavily inked parts). Drawn by Katherine Bryan. 



151 



