22 MASS. EXPERIMENT STATION BULLETIN 388 



making a total of 173 cities and towns in which the disease has been found in 

 Massachusetts. Also, a fungus, Verticilliuni sp., was isolated from elms in 8 

 communities in which it was not previously known, and reports show a total of 

 96 municipalities in which this fungus has been found in woody plants in Massa- 

 chusetts. 



The extended period of dry weather during the summer of 1941 was a serious 

 cause of tree injury, and therefore, additional trouble associated with winter 

 injury may be expected from this source next year, especially in the case of ever- 

 greens, which commonly experience winter injury even in years of normal rainfall. 



Because of outbreaks cf elm pests during the summer of 1940, a circular^ was 

 prepared this year and distributed to meet the demands for information on the 

 subject. 



A disease known as bleeding canker of hardwoods has been reported to be 

 increasing in New England and, at least under certain conditions, the writers 

 have seen cases in which attempted remedies have caused more damage than 

 the fungus. A fungus, Phytophthora cactorum, has been described* as the cause 

 of the disease, and an organism believed to be the same fungus has been isolated 

 by the writers from elm, maple, beech and oak in Massachusetts, although 

 evidence of serious disease in the host was not always conspicuous. A possible 

 injection treatment emplojnng "Helione Orange" and requiring skilled tech- 

 nicians has been described^ following preliminary experimental work. Critical 

 evaluation of the results may be possible at seme later date; for the present, 

 however, specific recommendations cannot be made. 



Current miscellaneous activities of the project included the preparation of 

 parts of the program of the annual Five-day Short Course for Tree Wardens, 

 the compiling of a progress report, ^ the discussion of wood-destroying fungi^ at 

 the Eastern Pest Control Operators' Conference, and the preparation of news- 

 paper press releases. 



The Importance of the Investigatio7i of Tree Diseases in National Defense. 

 In this brief outline of phases of the project which have expanded in relation to 

 national defense, it should be pointed out that it is not possible to distinguish 

 sharply between basic and emergency activities. In fact, none cf the following 

 activities are completely new to the project, but increased demands on the part 

 of the public have been classified under three arbitrarily selected groupings 

 among which there is considerable overlapping. 



1. Housing projects, new real estate developments, and increased prosperity 

 in general have resulted in increased interest in trees and tree diseases around 

 homes and along streets and highways. 



2. As lumbering operations near the point of demand for wood have in- 

 creased, owing to the necessity for curtailment of transportation costs, supply 

 of labor, shortage of materials, etc., certain types of forest-tree diseases have 

 increased both in the forest and in nearby ornamental trees. The practice of 

 cutting only mature forest trees as a crop maintains a highly desirable, relatively 

 stable biological balance, but only about 5 percent of the nation's forests are 

 operated on this basis in normal times and no hope for an increase in yield-basis 

 operations can be held in the present emergency. 



''McKenzie, M. A., and Becker, W. B. Timely spraying protects elms against midsummer 

 defoliation. Amherst, 1941. 



'Howard, F. L., and Caroselli, N., Phytopathology 30:11. 1940. 



^Howard, F. L. Science 94:2441 :345. October 10, 1941. 



^Transcriptions of certain papers presented at the eighth annual five-day short course for tree 

 wardens and other workers with trees. Amherst, March 24-29, 1941. 



'McKenzie, M. A. Wood decay fungi, published in the "Proceedings of the First .\nnual Eastern 

 Pest Control Operators' Conference," Amherst, January 13, 14, and 15, 1941. 



