UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 727 4 
Contribution from the Bureau of Plant Industry ; 
WM. A. TAYLOR, Chief 
Washington, D. C. PROFESSIONAL PAPER December 18, 1918 
ANTHRACNOSE OF CUCURBITS.' 
By M. W. Garpner, Scientific Assistant, Cotton, Truck, and Forage Crop Disease 
Investigations. 
CONTENTS. 
Page Page 
Scope of the investigation..........-...---- 1 | Relation of the fungus to the host tissue..... 24 
MVCICHSCASCee tens he ee ieee oe Geese sito oele = 2 | Life history of the causal organism in relation 
ET OSES aoe a eres ciecresisiee ie cist see ee elie 2 TOMO GISCASC 4a ete es 2 8 Oe | pa ae eset 29 
ISCO As Se agoanoRoU DGoee SoaranCenooede 3 Seasonal development.................- 29 
Geographic @istriburionwesss secs eens 6 Local dissemination by water and other 
Heonomicimportance..-2-.22.2..-.---.- 8 APCNCIES 228 sain ce eke wot shee aemases 34 
WDESCHIPLIOME NS Sek Dae ee ec al’ ates 10 Dissemination with the seed........-...- 44 
Mhyreycausaltorsanisimeense-sassec: oeee eee eee 12 Overwinterings teases ee en eee ae ee 56 
MRA XO OMY Kersten ete Wok asa le Sens eS 12) Ny Comtrole. seca tetera settee: ete cee es aathicees 58 
Morphology and cultural characters... .- 15 SPLRAVAM oes ae cso ee Sere ire eeuneeeyes 59 
Phy SiOlogyenene senna ee eee eet eee ne 18 Seed disinfection and crop rotation...... 60 
Ra thoreni Cline pacer re eeerecraeceree ee bed lea Unidad ATVs etre iste cess Sac ate eS ioe eee 62 
Relation to other anthracnose fungi...... 24) iterature! cited: stscsee-aas sete = seoeieeeen 65 
SCOPE OF THE INVESTIGATION. 
Anthracnose of cucurbits is a common and widely distributed dis- 
ease of the cucumber, muskmelon, watermelon, certain gourds, and 
a few other cucurbits. It is apparently limited to this family of 
host plants. 
The disease is caused by the fungus Colletotrichum lagenarvum 
(Pass.) Ell. and Hals., and is characterized by sunken or discolored 
lesions on the leaves, stems, and fruits of its host plants. These 
lesions are not limited in size, and under certain conditions the 
1 The data here presented were obtained as the result of a cooperative arrangement between the Bureau 
of Plant Industry, the University of Wisconsin, and certain cucumber growers during the seasons of 1915, 
1916, and 1917. The writer, as a graduate student, was designated by the University of Wisconsin to 
carry out its part in the cooperation, which also extended to Indiana and Michigan under the leadership 
ot W. W. Gilbert, of the Bureau of Plant Industry. Most of the laboratory studies herein reported were 
conducted in the laboratory of plant pathology of the University of Wisconsin, and the article itself was 
presented to the faculty of that university in partial fulfillment of the requirements for the degree of doctor 
of philosophy. 
The writer wishes to acknowledge his indebtedness to Prof. L. R. Jones, of the University of Wisconsin, 
for supervision and helpful suggestions throughout the progress of this work, and to Dr. W. A. Orton, 
Mr W. W. Gilbert, and Dr. E. Carsner for their assistance and cooperation. 
69806°—18—Bull. 727——1 
