50 



ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 46 



(Fig. 46). Many elms which show leaf symptoms after early 

 August live over winter, produce a sparse crop of leaves the next 

 spring, and die in late June or July. Since these leaf symptoms 

 frequently can be confused with those caused by other elm dis- 



Fig. 48. — High-powered mist blowers may be used to obtain adequate 

 coverage of large elms with methoxychlor or DDT for protection against 

 the insect that carries the phloem necrosis virus. Thorough spraying of 

 foliage and crotches of young shoots is very important. 



