ANNUAL REPORT, 1935 25 



rooted well when inserted in sand in the greenhouse on May 20 to 24. Similarly 

 inserted and at the same time, cuttings of the following species rooted poorly 

 or not at all: Calycanthus floridus, Prunus triloba, Rhododendron minus, Rhus 

 canadensis, and Stephanandra Tanakae. 



All cuttings of Viburnum fragrans rooted when inserted June 21, but less 

 than one-third rooted when inserted July 10. V. Sieboldii also rooted better 

 when taken early. 



Taken June 21, V. fragrans and Corylopsis pauciflora rooted as well in sand 

 and peat moss as in sand. Rhododendron calendulaceum rooted better in sand. 

 Gordonia alatamaha rooted fairly well in sand, but did not do well when trans- 

 planted to soil (pH 6.0). 



Buddleia alternifolia, Philadelphus coronarius, Viburnum bitchuiense and V . 

 Carlesii did not root so well in soil as in sand or in sand and peat moss. The 

 unfavorable effect of soil is not attributed to fungi present, for the cuttings died 

 without previous evidence of decay of tissue, and results were the same in soil 

 variously sterilized. 



The use of acetic acid dusts, harmless to seedlings, was followed by some 

 defoliation of cuttings of Bruckenthalia spiculifolia, Erica vagans, Ilex crenata, 

 and /. opaca inserted immediately after treatment of the rooting medium (sand 

 and peat moss). 



The only chemical treatment of sand which gave indications of any stimu- 

 lation of rooting of softwood cuttings, in this case Lonicera syringantha and 

 Styrax americana, was copper-lime dust 16 gms. 



Softwood cuttings of 13 species rooted no better in sand or sand and peat 

 when the media received the following treatments, than in these media without 

 treatment: acetic acid 4 c.c, formaldehyde 6 c.c, tannic acid 12 gms., potas- 

 sium permanganate 15 gms., and magnesium peroxide 2.5 gms. 



Growing in inoculated soil, cuttings of Taxus media taken in October were 

 much less susceptible to infection by a strain of Pythium debaryanum than were 

 seedlings of herbaceous plants; but cuttings of Taxus baccata repandens, 

 similarly exposed, were infected and killed by a strain of Rhizoctonia solani. 



Germination of the seeds of Rhododendron molle and early growth of seedlings 

 was improved by salicylic acid 3 gms. applied to a mixture of sand, peat moss, 

 and soil. 



Apple Rust. (C. J. Gilgut, Waltham.) A great reduction of rust (Gym- 

 nosporangium juniperi-virginianae Schw.) on Wealthy apple leaves was ob- 

 tained by the use of several fungicides. Six applications each were made of 

 Flotation sulfur, Linco colloidal sulfur, liquid lime-sulfur, and a combination 

 spray consisting of liquid lime-sulfur, calcium arsenate, and aluminum sulfate. 

 The first applications were made to conform to the pre-pink bud stage of tree 

 growth; the last, on June 14, corresponded to about three weeks after calyx 

 time. The percentage of control was 88, 92, 96, and 95 respectively. The 

 results were computed on the basis of percent control for the trees given no 

 treatment. 



This work was done in cooperation with Dr. J. H. Faull of Harvard Univer- 

 sity and Dr. J. D. MacLachlan, one of his graduate students. 



Shade Tree Disease Survey of Massachusetts. (A. Vincent Osmun and 

 Malcolm A. McKenzie.) A survey to determine the presence, distribution 

 and importance of shade tree diseases in the State was carried on during the 

 summer of 1935. The work was financed jointly by State appropriations to 

 the College and State Department of Agriculture, a State-wide F. E. R. A. proj- 



