50 Nebraska Agricultural Exp. Station, Research Bui. 10 
Practically resistant Moderately resistant Susceptible 
Northwest Greening Early Harvest 
Rome Beauty Fameuse (Snow) 
Delicious King David 
Red Astrachan Chenango 
Wolf River Paragon 
Malinda 
Willow Twig 
Stayman Winesap 
Chicago 
Utter (Red) 
Scab was always found to be more prevalent where no cultiva- 
tion was practiced and decidedly less in evidence where thoro, 
early and late cultivation was practiced as in the case of the 
Beavers orchard at Omaha. 
Well pruned and spaced trees were as a rule less scabby than 
trees which carried a dense foliage or which were so close together 
that the branches interlocked. This should be expected, since 
the more dense the foliage the longer the tree will remain moist 
and afford the best conditions for the germination of spores. 
It was noticed that trees situated on high, rolling land were 
usually not so badly infected as trees on lower ground. This is 
due in part to the better circulation of air on the rolling land and 
in part to the dense foliage found on trees growing in low places, 
especially where proper pruning is not given. 
SUMMARY 
The foregoing records and observations lead to some more or 
less general conclusions. 
Sanitation, i.e., the removal of old leaves, windfalls, and mum- 
mied apples, together with clean culture, will go a long way to- 
wards controlling the primary infection. 
The proper spacing of the trees in an orchard, together with 
good air drainage and the right amount of pruning, will lessen 
the infection to some extent. However, even with an ideal 
orchard and the best methods of sanitation, clean fruit cannot be 
grown in Nebraska unless the orchards are properly sprayed. 
The evidence presented shows that spraying will control the 
disease if applied at the proper time and that this time depends 
upon the time of infection. The spray must be applied before the 
infection in order to prevent injury. Therefore, since it has been 
proved that there is always more or less infection at or just before 
the time the blossoms are out if the weather conditions are 
favorable, it follows ,that spraying for scab must be done before 
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