26 MASS. EXPERIMENT STATION BULLETIN 315 



on damping-off and on germination and growth of plants. 3 Liquid treatments 

 were applied to soil (3 inches deep in flats) at the rate of 2 quarts per square foot. 

 The number of grams applied per square foot is indicated below. Reference is 

 here made to post -germination damping-off only. Effects on growth as here 

 mentioned are confined to young plants. Conclusions are tentative, not final. 



There was no control of damping-off by betanaphthol 4 gms., calcium sulfite 

 5 to 30 gms., calcium sulfate 15 to 45 gms., charcoal (wood, powdered) 25 to 

 100 gms., cupric carbonate 2 to 4 gms., naphthalene 20 to 40 gms., o-cresol 10 

 gms., pentachlorethane or tetrachlorethane 5 to 12 gms. 



There was partial, but not always satisfactory control of damping-off by acetone 

 1:20, aluminum sulfate 30 but not 25 gms., ammonium acetate 40 but not 25 

 gms., ammonium sulfocyanate 8 but not 6 gms., calcium acetate 20 to 60 gms., 

 calcium chloride 20 to 25 gms., calcium hypochlorite 12 to 16 gms., calcium sul- 

 focarbolate 25 to 50 gms., metallic copper (powdered) 8 to 12 gms., copper aceto- 

 arsenite 2 to 4 gms., cuprous cyanide 1 to 4 gms., copper sulfate 3.5 to 5.5 gms., 

 copper sulfocarbolate 6 but not 5 gms., copper-lime dust (80-20) 20 to 30 gms., 

 potassium permanganate 30 to 50 gms., sulfuric acid (sp. gr. 1.84) 6 to 15 gms., 

 zinc oxide 20 to 25 but not 15 gms., and zinc sulfate 10 to 16 gms. 



Damping-off was well controlled by ammonium hydroxide 1:30 to 1:50 (but 

 not 1:60), calcium cyanamide 12 to 16 gms., and raw pyroligneous acid 4:100. 



Certain treatments injurious to some species were harmless or even beneficial 

 to other species. 



Growth of the following species was improved by the treatments indicated: 

 Campanula medium and Digitalis purpurea by acetone 1:60 and 1:70; Dianthus 

 (9 species) by aluminum sulfate 20 gms.; Erysimum asperum, beet, and cucumber 

 by ammonium hydroxide 1:50 (10 days before seeding); Reseda odorata and beet 

 by calcium chloride 15 gms.; Brunnera macrophylla, Scabiosa atropurpurea, 

 Alyssum argenteum and beet by calcium cyanamide 10 gms. (10 days before seed- 

 ing); sweet pea by calcium sulfate 20 to 30 gms.; Verbena hortensis by calcium 

 sulfocarbolate 5 to 10 gms.; Tropaeolum majus by charcoal 25 to 100 gms.; 

 Althaea rosea by cupric carbonate 4 to 6 gms. and by cuprous cyanide 2 to 3 gms.; 

 sweet pea and Ageratum Houstonianum by copper sulfocarbolate 3.5 to 4 gms.; 

 Arabis albida, Cypsophila repens, Althaea rosea, beet and cucumber by potassium 

 permanganate 25 to 40 gms.; and Lupinus polyphyllus by zinc oxide 15 to 20 

 gms. 



Apple Rust. (E. F. Guba, Waltham.) In cooperation with Dr. J. H. Faull 

 of Harvard University, a small test was conducted to determine the effectiveness 

 of fungicides in controlling apple rust {Gymnosporangium juniperi-virginianae 

 Schw.) on Wealthy apple. The results indicate that sulfur fungicides have some 

 value in reducing the amount of infection, but the best of the five materials 

 tested, namely, liquid lime-sulfur and a colloidal paste called Linco, did not 

 reduce infection more than 50 percent of that shown by the controls. 



Plant Containers. (L. H. Jones.) An effort is being made to develop a plant 

 container suitable for growing young trees and shrubs in nurseries. The adoption 

 of pot culture in nurseries would lessen the care required in establishing the 

 plant in its permanent location. 



The non-toxic effect of copper containers was confirmed by using barley as an 

 indicator plant. Barley is said to be susceptible to small concentrations of copper, 

 the effect being noticed by the lack of formation of grain heads. Tests showed 



•For earlier work, tee Mass. Apr. Kxpt. Sta. Bui. 305, pp. 19-21, 1034. 



