86 



ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 46 



Twig blight, the first stage, occurs before leaves emerge in 

 the spring and results in killing of the tips of small, 1-year-old 

 twigs (Fig. 83). Small, black fruiting bodies of the fungus soon 

 appear in the bark of the killed twigs. In time, cankers form and 

 affected twigs may be girdled. Repeated annual killing of twigs 

 results in gnarled or brushy branch growth (Fig. 84). 



Bud blight, the second stage, occurs as the buds begin to ex- 

 pand in April or early May. Girdling cankers produced by the 

 fungus kill the buds before bud caps begin to break (Fig. 85). 



Shoot blight, the third stage, is conspicuous as sudden dying 

 of expanding shoots and young, immature leaves on affected 

 branches (Fig. 86). This blight and death of young leaves is 

 often confused with frost injury. 



Leaf blight, the fourth stage, is produced by direct infection 

 of expanding or mature leaves. The infection results from the 

 fungus spores produced on twigs and branch cankers (Fig. 87). 



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Fig. 84. — Severe twip blight of sycamore for several successive years 

 results in gnarled or brushy branch growth. 



