218 DISEASES OF CULTIVATED PLANTS 



which was present in abundance in the friable, whitish, broken 

 up epidermis, it again proved to be the Ascochyta or conidial 

 form of Mycosphaerella citrullina. Experiments conducted at 

 Kew proved that the fungus developed on cucumber plants 

 would infect young tomato plants, and that spores from diseased 

 tomato plants would infect vegetable marrows. In both cases 

 the plants infected produced the conidial form of the fungus 

 within a fortnight, and in both instances the lesions formed 

 were characteristic. The ascigerous condition of the fungus 

 has not been observed at Kew. 



Can this, like the A. M. G., or so-called American goose- 

 berry mildew, be considered as another affliction imported 

 from America? This I consider to be doubtful. Melon, 

 cucumber, and tomato plants do not come to us from the 

 United States in a growing condition, if they come at all, and 

 probably the fungus is with us under some other name, but I 

 have not before observed it as a destructive parasite, neither 

 have I seen it described as such. The fungus does not attack 

 the fruit. 



Ascochyta form. Perithecia depressed globose, with a 

 minute apical pore, parenchymatous, wall thin, pale brown, 

 90-150 p. diam., crowded; conidia hyaline, oblong, ends 

 rounded, becoming i - septate, usually constricted in the 

 middle or slightly dumbbell-shaped, averaging 14x4-5 /*. 



Ascigerous form. Perithecia roughish, dark brown to black, 

 depressed globose, ostiolum slightly prominent, erumpent, 

 and finally almost superficial, densely scattered, ioox 165 /x; 

 asci cylindric-clavate, spores i- septate, hyaline, elliptic- 

 oblong, slightly constricted at the middle, distal cell often 

 largest. 



This fungus appears to be in the wrong genus. I leave the 

 rectification to the author. 



The disease is evidently a deadly one ; a grower stated that 

 ' the plants fall over like ninepins, nine or ten a day.' The 

 only thing to do is to remove and burn infected plants on the 

 first sign of the disease, as apparently when once attacked 

 recovery is impossible. Spray remaining plants, also the soil, 

 with Bordeaux mixture. 



Grossenbacher, J. G., N. Y. Agric. Expt. Sta., Geneva, 

 N.Y., Technical Bull. No. 9 (1909). 



