192 REPORT OF THE BOTANICAL DEPARTMENT OF THE 
sistance to blight is a desirable quality in a variety, but is less 
important than several other qualities. Wherever late blight © 
occurs potatoes must be sprayed anyway, and the slight differ- 
ences in the blight resistance of the different varieties does not 
amount to much. Most of the blight-proof varieties advertised 
are humbugs.” 
BEST TIME TO DIG BLIGHTED POTATOES. 
“When potatoes are attacked by late blight there is always 
danger that the tubers may rot. The question is frequently 
asked: ‘How soon after the tops begin to blight should the 
tubers be dug in order to avoid, as far as possible, loss from 
rot?’ .This subject has been investigated by Professor Jones at 
the Vermont Experiment Station (Fifteenth Annual Report, 
pp. 219-223), who sums up the results of his experiments®’ as 
follows: ‘As nearly as we can formulate a rule based upon these 
results, it is that where there is danger of rot it is best to delay 
the digging some ten days or more after the tops die and that 
a longer delay does no harm.’ 
“Our own observations lead us to a similar conclusion. If 
the tubers are to be stored they should not be dug until the tops 
are dead and thoroughly dry, in order that the fungus spores 
may be given a chance to dry up and die. As long as the tops 
remain even partially green the spores of the blight fungus con- 
tinue to live. In the process of digging, the tubers become 
covered with these live spores, and if conditions are at all favor- 
able more or less rot results. This explains why sprayed pota- 
toes sometimes rot more in storage than unsprayed ones. 
. “In this connection attention should be called to the objec- 
tionable practice of covering piles of tubers with potato tops to 
protect them from the sun. If the tops have been affected with 
late blight, they may infect the tubers and cause them to rot. 
The danger is especially great if the tops are green or if rain 
comes while the tubers are thus covered.” 
A PUBLIC SPRAYER. 
With farm help so difficult to obtain as at present, farmers are 
inclined to look with disfavor upon any new method involving 
A later experiment giving similar results is reported in Vermont Agr. 
Exp. Sta. Rep. 16:161-163. See also Me. Kxp. Sta. Bul. 112:2. 
