Diagnosing Injury to Eastern Forest Trees. A Manual for Identifying Damage Caused by Air Pollution, Pathogens, Insects, and Abiotic Stresses

Pennsylvania

1987

122 S.

zahlr. Abb.

Serie

12742

400084892

The purpose of this manual is to assist members of the National Vegetation survey in Recognizing air-pollutant-induced injury and in identifying disease and insect damage that may be confused with air pollutant-induced injury to forest vegetation in the eastern United States. Ozone, sulfur dioxide, and, to a limited geographic extent, hydrogen fluoride, are all pollutants of concern in relation to forest vegetation; detailed descriptions of the injuries caused by these pollutants are presented herein. A second section of this manual has been prepared to assist the Survey in recognizing other major diseases, insects, and abiotic stresses that may be found at the survey plots. these disorders were chosen because their symptoms may be similar to those caused by air pollutants. Basic information and the most typical symptoms for each of these causes of stress are also presented photographically. It is important that both sections of this manual be consulted thoroughly to relate field symptoms accurately to the most likely cause of the observed symptoms. In all cases, the presence of biotic pathogens, insects, and other indicators of plant stress should be investigated and recorded. Finally, this manual has been designed to minimize errors in identifying the actual causes of symptoms evident in each plot. All potential causes must first be eliminated before the injury is ascribed to an unknown cause. Survey crews should follow carefully the prescribed sampling and/or searching techniques for causal agents as outlined in this manual. Individuals should also consult other references to identify disease and insect problems that may not be covered in this manual.