VEGETABLE AND FIELD CROPS 



221 



Powdery mildew (Erysiphe polygoni DC.)- — This mildew 

 of the cucumber and cantaloupe in general appearance 

 resembles that described for the grape. It is more com- 

 mon under glass 

 than in the open, 

 and here indicates 

 too much moisture 

 and too little ven- 

 tilation. It is sel- 

 dom injurious in the 

 field. 



Flowers of sul- 

 phur applied to 

 the hot water or 

 steam pipes in the 

 form of a paste is 

 useful. 



Leaf blight, cer- 

 cosporose {Cercos- 

 pora Cucurbitoe Ell. 

 &Ev.). — The spots 

 of this disease are 

 much hke those of 

 alternariose, but are 

 of lighter brown 

 color and more angular form, being limited by the veins. 



Bacillose, rot (Bacillus melonis Giddings). — This soft 

 rot was described first by Giddings ^ as causing 25 per cent 

 loss in certain fields in Vermont in 1907. The decay 



' Giddings, N.J. Sci. n. o. 29, 911, June 4, 1909; also Vt. Agr. Exp. Sta. 

 Bui. 148, 1910. 



Fig. 102. — Sclerotium Rolfsii Sacc. in litt. growing 

 upon a cantaloupe at point of contact with the soil. 

 After Hume. 



