PLATE B 
1. —Healthy barley leaf for comparison. 
2. —Early stage of bacterial blight (natural infection) showing a translucent, water- 
soaked stripe along the midrib, yellowing toward the apex. Often such lesions as this 
will be studded with exudate granules (see PI. 47, D) or show a drop of bacterial ooze 
at the base (see PI. 47, B). 
3. —More advanced stage of bacterial blight of barley (natural infection) where nu¬ 
merous local invasions have developed. Note the many water-soaked spots; the glis¬ 
tening grayish exudate scales below, which are shown in sharper color contrast in this 
painting than in nature. The tissues, as in the more advanced lesions above, com¬ 
monly retain their translucence as they yellow and die because of the hardened bac¬ 
terial ooze retained within. 
4. —Barley seedling showing abundant infection spots on the lower leaf from atom¬ 
izer inoculation with strain isolated from old infected seed. The individual greenish 
water-soaked spots represent stomatal infections. The general dying and yellowing 
above resulted from such invasions. 
5. —Barley seedling similarly infected with strain isolated from blighting leaf. 
(644) 
