NOTES ON VARIOUS PLANT DISEASES.* 
FE. C. STEwART. 
SUMMARY. 
J. During the season of 1898 a bacterial rot caused heavy 
losses to the onion growers in Orange Co., N. Y. The onions 
were found to be affected at harvest time. One or more layers 
of the onion would be soft rotten while the adjacent layers were 
sound. Sometimes the rotten layers were on the interior, in which 
ease the affected bulbs might be difficult of detection; or the rot 
might be confined to the outermost fleshy layer, producing the 
so-called slippery onions. Although this rot is quite certainly due 
to bacteria, it is not readily produced by inoculation with diseased 
tissue except in the presence of water. This shows that water is 
an important factor in the rot and that the unusually large amount 
of rot in 1898 was due to the excessively wet weather which oc- 
curred in July and August of that year. Thorough drainage and 
clean cultivation are recommended as preventive measures. 
II. Leaves of field cucumbers affected with a powdery mildew 
have been received from Athens, Pa. This is believed to be the 
first record of the occurrence of powdery mildew on field-grown 
cucumbers in America. In greenhouses it isnot uncommon. The 
identity of the fungus is uncertain, but it is probably different 
from the powdery mildew occurring on squashes and pumpkins. 
IIT. A dodder, Cuscuta gronovw Willd., has occurred on green- 
house cucumbers at the Station. Plants affected with this parasite 
should be immediately destroyed to prevent it from spreading. 
It is very aggressive. 

* Reprint of Bulletin No. 164. 
