ANNUAL REPORT, 1943-44 19 



for treatment or disposition of the elm material involved. Timely selective 

 treatment is a most important consideration in the control of the disease, and 

 the Massachusetts Tree Wardens' and Foresters' Association, together with 

 Local Moth Superintendents, have planned regional meetings throughout Mass- 

 achusetts for the summer to formulate further plans for Dutch elm disease control 

 throughout the State. 



At the present time, surveys and recommendations for control practices are 

 made by the Experiment Station in regions where the disease occurs, and sanita- 

 tion practices are performed by the Massachusetts Department of Agriculture 

 and the municipalities and property owners concerned. Elm material found to 

 be infested or suitable for infestation by carrier beetles should be utilized as fuel 

 or debarked by June 1 in any year, as a means of checking the increase in the 

 population of the vectors of the disease. Tree wardens, foresters, arborists, fire 

 wardens, highway departments, state departments, and public utilities have 

 materially aided in this practical method of protecting disease-free elms, and 

 other means of treatment are being explored constantly in cooperation with the 

 Department of Entomology. 



Other Tree Problems. Fifty-six diseases of thirty-two species of trees including 

 eight diseases of elm were identified from approximately 320 specimens and 

 inquiries received during the year. The Cephalosporium wilt of elm was reported 

 from one additional municipality in which the disease has been found in Mass- 

 achusetts. Verticilliuni sp. was isolated from several species of woody plants, 

 and one specimen was collected in a municipality from which the writers had no 

 previous report of the fungus. 



Soon after the leaves developed in 1943, wilting of foliage occurred on maple 

 trees in all parts of the State. In some cases trees died, especially Norway maples, 

 while individual branches commonly were affected also on sugar maple. Several 

 factors were involved, but the only fungus isolated which is known to be a primary 

 cause of disease was Verticillium sp. Field studies will be continued during 1944 

 in locations where affected trees were reported. 



Rust of red, green, and possibly other species of ash trees, caused by Puccinia 

 peridermiospora (Ell. & Tr.) Arth., was particularly prevalent in the coastal 

 regions of Massachusetts during early summer. Because of the large number of 

 inquiries received concerning this disease, a circular was prepared to facilitate 

 the handling of requests. 



An unusually large number of shade and ornamental trees, particularly e\'er- 

 greens, died or failed to produce satisfactory foliage in 1944. Contributing 

 factors were presumably the drouth of the previous summer, deep freezing of the 

 ground in a relatively dry condition in the absence of snow cover in winter, bright 

 sunlight of winter, and drying winds. Previous to the appearance of widespread 

 injury, recommendations for maintaining street trees in a safe condition and for 

 pruning diseased parts of trees, treatment of tree wounds, sanitation practices, 

 and the use of disease-resistant trees were prepared for municipal tree depart- 

 ments. More recently, a report on tree damage in association with winter con- 

 ditions has been prepared. 



Foliage of trees throughout the State, in common with many food plants, 

 suffered from the effects of the heavy frost on May 19 and 20, 1944. In some 

 cases all leaves on trees were destroyed, while all degrees of leaf injury from slight 

 to relatively extensive were also noted. Among the more common trees, syca- 

 mores, oaks, beeches, sumacs, walnuts, butternuts, hickories, maples, alders, and 

 elms, in order of listing, were injured more or less significantly; but doubtless 

 many other woody plants with soft growth were also affected. 



