232 



DISEASES OF ECONOMIC PLANTS 



as well as in the field. It is well to sulphur the greenhouses 

 thoroughly when empty and to clean and whitewash 



Fig. 109. — Spots of downy mildew upon cucumber leaf. After Orton. 



all walls and wood in order to kill any fungi present. 

 Should the disease appear, spray at once as in field practice. 

 For direction for field spraying see cucurb sprajang. 



Anthracnose (Colletotrichum lagenarium (Pers.) Ell. & 

 Halst.) . — Upon the cucumber leaf this disease makes circular, 



