190 



Diseases of Economic Plants 



Spraying with Bordeaux mixture is recommended; also 



turning the melons so as to expose all sides to light and air. 



Wilt ^-° (Mijcosphcerella citndlina (Sm.) Gr., Diplodina). — 



This wilt or canker seems to be rare, perhaps affecting to 



serious extent greenhouse-grown 



muskmelons; only occasionally 



field muskmelons and other 



cucurbits. 



Infection is local at the nodes 

 in the leaf axil, never at inter- 

 nodes. The edges of the infected 

 areas are "oily green" in color, 

 often with resin-colored, gummy 

 exudate. The older parts are 

 either dark and gummy, or dry 

 and gray, and bear many brown 

 pycnidia. 



Spraying with Bordeaux mix- 

 ture after the plants are about 

 half grown, but before the dis- 

 ease appears, and often enough 

 thereafter to cover growing 

 parts, is recommended. 



Minor diseases 



Leaf-spot (Phyllosticta cucur- 

 hitacearumSacc.) on muskmelons 

 has been destructive in several 

 states, notably so in New Jer- 

 sey and Ohio. The spots are 

 light-colored and pycnidia ap- 

 pear in their centers. 

 A Leaf-spot *^^^ (Stemphylium cucurbitacearum Osn.), 3-4 

 mm. in diameter, circular or irregular in outline, visible from 

 both sides of the leaf, with centers yellow-brown and red 

 bordered, is reported from Indiana and Ohio as causing 

 some loss. 



Fig. 105. — • Portions of musk- 

 melon vine showing pycni- 

 dia and perithecia of Myco- 

 sphserella. After Dorsey. 



