ANNUAL REPORT, 1934 25 



creasing ratios up to 2 pounds of powder to 1 pound of acid to 1500 cubic feet 

 was ineffective. Formaldehyde gas generated from 9 ounces of 40 percent formalde- 

 hyde solution with 6 ounces of potassium permanganate in 1500 cubic feet for 

 12- to 24-hour periods in any number of treatments was efficient for all practical 

 purposes. 



The optimum temperature for growth of the causal organisms in general is 

 approximately 78°F., with a few exceptions having a higher or lower optimum 

 within the range of 75° to 85°. The maximum temperature for growth is in the 

 range of 92° to 97°, and the minimum generally at approximately 40°, the excep- 

 tions at 33° to 35°. 



Infection at the blossom end and particularly at the stem end of the squash 

 is of major importance in loss from decay. Injuries in the rind at harvest become 

 overgrown with a firm, thick callus. Inoculations with decay-producing fungi at 

 injuries in the rind during the harvesting season rarely were followed by decay. 



The curcurbit wilt bacterium (Bacillus tracheiphilus E. F. S.) outranked all 

 other causes of decay combined. 



Tests were conducted to determine the relation of seed inoculation with decay 

 organisms and seed disinfection with chemicals to yield and keeping quality of 

 squash, but results do not warrant a report at this time. The trend of the work 

 suggests the importance of insecticidal and fungicidal treatments in the 

 field and cold storage of the harvested crop, study of which is planned in the 

 future. 



Strawberry Gold Leaf or Yellows. (E. F. Guba, Waltham.) One and one- 

 half acres of land were planted to yellows-free and otherwise disease-free Howard 

 17 for plant production. A supply of more than 100,000 plants for distribution 

 to Massachusetts growers will be available in 1935, all of which appears to be 

 engaged. 



Carnation Blight. (E. F. Guba, Waltham.) The following are some of the 

 newer varieties of carnations studied for their reaction to the blight fungus 

 (Alternaria dianthi S. & H.): 



Slightly Susceptible Resistant 



Scarlet Monarch Orchid Beauty 



Light Pink Abundance Bonanza 



Donna Lee Mrs. M. Beuerlein 



Ocean Spray 

 Joy 



Chief Kokomo 

 Mary E. Sim 

 Oxymethylene dusts (6 percent), mixed with sand in the bench in the propor- 

 tion of 1.5 ounces per square foot, were injurious to the cuttings even after a 

 delay of 72 hours in planting. Potassium permanganate solution 1-1000, applied 

 as a drench to bench sand inoculated with Alternaria and Fusarium sp., was not 

 a satisfactory treatment for controlling infection of the cuttings although the 

 results are not to be considered final. Old solutions of potassium permanganate 

 appeared to be as satisfactory as new solutions for disinfecting carnation cut- 

 tings and on root action, although the results are considered indicative rather 

 than final. 



Diseases of Herbaceous Ornamental Plants Caused by Soil-Infesting Fungi. 



(W. L. Doran.) Work has been continued on the effects of certain soil treatments 



