UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT BULLETIN No. 1461 
Washington, D. C. 
November, 1926 
CONTROL OF CUCUMBER MOSAIC BY ERADICATION OF WILD HOST PLANTS 
By S. P. Doolittle, Pathologist, and M. N. Walker, formerly Junior Pathol- 
ogist? Office of Vegetable and Forage Diseases, Bureau of Plant Industry 
CONTENTS 
Page 
Introduction 1 
Experiments of 1920 2 
Rockland, Wis 2 
Marengo, 111 3 
Plymouth, Ind 3 
Results of work in 1920 3 
Experiments of 1921 .__ 4 
Rockland, Wis 4 
Marengo, 111 -._ 5 
Experiments of 1922 5 
Rockland, Wis 5 
Marengo, 111 6 
Page 
Experiments of 1923 at Rockland, Wis 
Experiments of 1924 at Rockland, Wis 
Summary of results at Rockland, Wis., 1920- 
1924 . 
Experiments at Madison, Wis., 1916-1924 
Experiments at Anna, HI., 1923 
Recommendations for mosaic control 
Summary 
Literature cited 
INTRODUCTION 
Cucumber mosaic is disseminated in the field by insects and by the 
handling of the vines incident to the cultivation and harvesting of 
the crop. In the case of pickling cucumbers the latter factor is of 
considerable importance, but insects are the chief agency in the 
spreading of the disease. The greater part of the insect dissemina- 
tion seems to be due to the melon aphis, Aphis gossypii Glover, but 
the striped cucumber beetle, Didbrotica vittata Fabr., and the 12- 
spotted beetle, D. 12-punctata Oliv., are also important as carriers of 
the disease. 
The first attempts to control mosaic consisted in the removal of 
mosaic cucumber plants as they appeared, together with the use of 
insecticides to reduce the number of insect carriers. It was found, 
however, that these methods were of little value in cases where the 
disease had become well established and where insects, particularly 
aphids, were present in considerable numbers (£). 2 
iThe writers are indebted to W. W. Gilbert, of the Office of Vegetable and Forage Dis- 
eases, for suggestions and advice during the progress of this work. 
The Department of Plant Pathology, University of Wisconsin, has cooperated in fur- 
nishing land and laboratory facilities necessary for certain phases of the investigations, 
and certain interested pickle companies and' "rowers have cooperated by furnishing 
funds and facilities for carrying on the work in the field. 
2 Italic numbers in parentheses refer to " Literature cited," p. 14. 
11139°— 26 
