THE MONTHLY BULLETIN. 



767 



Corrosion at the crown completely girdling the tree in extreme cases 

 and in others involving only part of the crown. Dead roots or at least 

 portions of some of the larger roots near the crown are common 

 symptoms. In all typical cases the injury to the bark begins on the 

 outer surface and gradually the arsenic eats its way through to the 

 cambium. The wood of liml)s. trunks and roots of injured trees is 

 more or less blackened. In most cases where injury is at all severe 

 girdling and death of the tree takes place. 



An interesting ease of similar injury to some young apricot trees was 

 seen in Kings County recently. Early in the season climbing cut- 

 worms gave considerable trouble by destroying the buds and in an 

 effort to rid the orchard of this pest the owner prepared a bran and 

 Paris green mash which he placed in generous piles about the crowns 

 of the affected trees. After a time the orehard was irrigated and 

 very soon the trees began to look sickly, many dying outright. When 

 the orchard was visited on October 28th some of the trees were still 

 alive but showed the characteristic symptoms of arsenical injury. An 



Fig. 404. — ^Young apricut orduiid injured by arsenical poisoning; note the uninjured 

 tree in tlie second row from the left. (Original.) 



examination of several of the crowns was made and the bark was found 

 to be more or less discolored and corroded in each case. In places it 

 was very black and could be crumbled easily between the fingers. 

 Above the ground line the bark was green and the top of the trees 

 showed a sickly, yellow color and an unthrifty growth to indicate the 

 crown and root condition. One of these trees is sliown in Fig. 408. 

 The portion of the trunk from the crown down, and some of the roots 

 were dead. Uninjured trees in the orchard were still in good foliage 

 and the picture gives an idea of the appearance of those that were 

 injured. Fig. 404 shows the portion of the on-hard where the injury 

 was done and gives some idea of the extent. 



It is probable that the presence of alkali in the soil and water, aided 

 in breaking down the Paris green, thus liberating soluble arsenic 

 which damaged the trees. 



This ease is cited, not for the purpose of alai-ming those who find it 

 necessary to use an arsenic compound in the form of a spray or other- 

 wise, but simply to show that care should be exercised in its applica- 

 tion. In spraying for codling moth there are times when much of the 

 liquid containing arsenate of lead, Paris green or zinc arsenite in 

 suspension, is allowed to run down the trunks of trees and collect at 



