33 



diseased limbs may be found long brown streaks in the heart- 

 wood by which the fungus may be identified. Vermicularia is 

 similar in its attack of limbs, but leaves no brown streaks in 

 the wood. It may be identified by the complete browning of the 

 diseased cambium. This browning may be seen by peeling back 

 the bark. Both of these diseases will kill a tree if allowed to 

 progress, but as they begin locally, they may be controlled by 

 careful pruning. 



Box Elders 



More than 2,000 box elders, or 11% of the trees of Danville, 

 were e.xamined and found to be in uniformly bad shape. They, 

 as well as the soft maple, have been topped and hacked. Only 

 36% were in a healthy condition and 64% needed care. They 

 were extremely tenacious to life and produced leaves even when 

 practically ready to fall from having been weakened by 

 rots. Twenty-eight per cent had been topped and were rotten, 

 and in addition 24% were gutted wath rots entering from 

 injuries and bad pruning. Gleosporium, a twig blight, was doing 

 considerable damage and 2% of the trees were severely injured 

 by it. 



Box elders are mainly obnoxious because of their numerous 

 insect pests. Practically every tree had a few box elder bugs 

 {Leptocoris trivittatus, Say.) and some were crimson colored 

 when the insects gathered on them in the sun. An extremely 

 heavy infestation of these insects occurred all over the city. 

 About 1% of the trees had tent caterpillars in them, but the 

 infestation was not heavy. The bagw^orms {Psyche) that attack 

 box elder trees had severely injured or defoliated 11% of the 

 trees. This heavy infestation was in local groups of trees at 

 different points in the city and could well have been controlled 

 by spraying. In some cases a single tree was topped, full of 

 heart rots, stripped by bagworms, infested with box elder bugs, 

 tip burned from the heat and infested with termites in the 

 rotted heart. 



Other Trees 



Information Concerning the remaining trees in the city is 

 given in Table 1. Those listed as healthy had good color in the 

 leaves, were in good structural condition and had no noticeable 



