Bui. 907, U. S. Dept. of Agriculture. 



PLATE II. 



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Fumigation of Citrus Plants With Hydrocyanic Acid. 



A, Comparative effect of hot sunshine and shade, after fumigation, on citrus plants with resist- 

 ant foliage. Immediately following the treatment two plants were placed in direct sunlight 

 and one in the shade, at 87° F., and held at parallel temperatures throughout the remainder 

 of the day. It is noted that leaves in the sun-exposed plants have abscissed at the base of the 

 blade. B, Citrus plants with tender foliage which were exposed immediately after fumiga- 

 tion to the sun or shade at 79° F. The plant in the shade had merely the tender tips injured. 

 All leaves and petioles of the sun-exposed plants were completely burned and cling without 

 abscission. 



