CHESTNUT BLIGHT 5 
on smooth shoots a sunken area, which usually has a smooth, un- 
cracked surface; but when it fails to kill the cambium, new layers of 
bark cells are formed underneath the attacked area and an enlarged 
lesion results. The swollen cankers usually have a number of 
longitudinal fissures or splits. (Fig. 6.) Frequently cankers have 
a smooth sunken area of bark in the center (fig. 6) and raised margins 
with cracks and fissures in the swollen parts. : 
Ficurp 3.—A swollen blight canker with suckers developed below the infected area 
On large thick-barked limbs and trunks a young blight infection 
causes very little change in the outward appearance of the bark. 
As the disease progresses abnornial splits or cracks often appear 
and expose some of the buff-colored infected inner bark, which is 
different in color from the surface bark. The presence of yellow, 
orange, or reddish-brown pustules about the size of a pinhead in 
