ANNUAL REPORT, 1946-47 17 



reported from two additional municipalities in the State. Verticillium sp. was 

 isolated from several species of woody plants. 



Anthracnose of maples and oaks, black spot of elms, and other leaf diseases 

 caused by fungi are prevalent on trees currenth'. In some instances premature 

 defoliation is traceable to this type of fungus infection. 



A needle blight of Colorado fir {Abies concolor) was found on specimens col- 

 lected at Newburyport, Mass. This disease is caused by the fungus Rehmiellopsis 

 balsameae. Under suitable conditions the resultant disease may become epiphy- 

 totic in plantations. Accordingly, the growth of the current season may be 

 rather uniformly scorched in appearance, resembling damage by late frosts to 

 which cause this fungus disease was formerly often attributed. Although the 

 disease was first known in Massachusetts on Colorado fir, later the causal fungus 

 was found on balsam fir (Abies balsaniea) in Maine. It seems assured that the 

 fungus is native in eastern United States on balsam fir and may have spread to 

 ornamental plantings of Colorado fir introduced into the vicinity. The disease 

 has not been found in the Western States, native range of the Colorado fir. 



Neglect of general maintenance work on street trees is increasingly important 

 as a cause of tree injury. The rising cost of this work to municipalities is the 

 primary factor involved. The result of the accumulation of weakened parts of 

 trees may be seen widely in the State following ordinary storms. Inevitable 

 accidents involving such trees may serve to direct needed action toward necessary, 

 constructive tree improvement and protection programs. 



Damping-off and Growth of Seedlings and Cuttings of Woody Plants as Af- 

 fected by Soil Treatments and Modifications of Environment. (W. L. Doran.) 



Work on the vegetative propagation of the Kudzu vine was continued and a paper 

 on the subject prepared for publication. Best results with this species were ob- 

 tained when cuttings, each made to consist of one node, its leaf and a young ax- 

 illary branch, were taken in mid-July, given a powder-dip treatment with indole- 

 butyric acid, and set in sand-peat. The rooted cuttings were wintered in the 

 greenhouse and, in cooperation with the Department of Agronomy, set in the 

 field in spring for later observations as to hardiness and growth. 



Work on the vegetative propagation of hemlock and of white pine was con- 

 tinued and a bulletin written and published about the latter.^ 



Different clones of hemlock, like different clones of white pine, were found to 

 respond very differently to treatments with the same root-inducing substance, 

 the best rooting being from more than 80 percent with some clones to less than 

 10 percent with other clones. Indolebutyric acid 150 to 200 mg./l., 20 to 18 

 hr., often improved the rooting of cuttings of hemlock taken in early winter; 

 but the rootiug of cuttings taken in October was more improved by naphthalene- 

 acetic acid 50 mg./l., 18 hr. 



Continued attention was given to the use of fungicides in combination with 

 root-inducing substances for the treatment of cuttings, and it was found that a 

 given fungicide when added to Hormodin No. 3, in the proportion of 15 percent 

 fungicide, does not have the same effect on cuttings of all species. Fungicides 

 which improved the rooting of summer cuttings when thus used were zinc ethylene 

 bisdithiocarbamate (HE178E), ferric dimethi-ldithiocarbamate (Fermate), and 

 zinc mercaptoben?othiazole with (leaf-bud) cuttings of a Rhododendron cataw- 

 biense hybrid; diphenyl guanidine phthalate (Gauntal) with cuttings of Viburnum 

 Carlesii; Fermate with flame azalea; 2, 3-dichIor-l, 4-naphthoquinone (Phygon) 

 with Cotoneaster adpressa, and HE178E with red cedar, Phygon was also safe 

 with Viburnum Burkwoodii. 



'Doran, W. L. Vegetative propagation of white pine. Mass. Agr. Expt. Sta. Bui, 435, 16 pp 

 illus. July 1946, 



