34 MASS. EXPERIMENT STATION BULLETIN 347 



after seeding, was harmful to cabbage; but 220 cc. similarly used did not injure 

 pepper or several species of Opuntia, the seeds of which, like those of pepper, 

 germinate relatively slowly. This amount of vinegar, 220 cc, prevented most 

 damping-ofT, but more than 200 cc. is not ordinarily to be used in this way with 

 safety to most species. The use of vinegar after seeding appears to be feasible and 

 details of method and dosage are now being further developed. 



Pyroligneous acid is being similarly used experimentally and with encouraging 

 results 



Different chemical powders were dusted on lettuce and cabbage seedbeds in 

 flats after firming the soil over the seed, and again upon emergence. On lettuce, 

 the stand was improved over the check 11 percent with red copper oxide, 5 

 percent with Basi-Cop, 1.6 percent with Vasco, 6 percent with calomel, and 

 2 percent with a 20-80 monohydrated copper-lime dust. On cabbage, the stand 

 was improved 18 percent with Vasco, 10 percent with zinc oxide, and 15 percent 

 with a 20-80 copper-lime dust. 



Control of Greenhouse Vegetable Diseases. (E. F. Guba, Waltham.) Since 

 the previous report, the tomato resistant to Cladosporium leaf mold has been 

 crossed back to the Waltham Forcing tomato for increase in size. Two genera- 

 tions of these crosses have been grown and selected for resistance and quality. 

 The resistance of these tomatoes has been confirmed by other investigators in 

 the United States and other countries. Their reports would indicate the oc- 

 currence of but one strain of the fungus. 



Carnation Blight caused by Alternaria dianthi S. & H. (E. F. Guba, Waltham.) 

 The relation of the newer varieties of carnations to blight was studied at Waltham, 

 and 72 distinct varieties of carnation were grown at the Jahn greenhouses at 

 East Bridgewater to observe their reaction to branch rot caused by Fusarium 

 dianthi, a serious parallel problem, in anticipation of the preparation of a per- 

 formance chart of the behavior of varieties to both Alternaria dianthi and Fus- 

 arium dianthi. All the Boston Ward types are very susceptible to both organisms, 

 but their superior quality otherwise may justify efforts at breeding for disease 

 resistance. 



Causes and Control of Decay of Winter Squash in Storage. (E. F. Guba and 

 C. J. Gilgut, Waltham.) Comparative studies were made of storage conditions, 

 amount of squash decay, and loss from shrinkage. The squashes used in these 

 studies were all from the same field. In a heated storage with the temperature 

 averaging 57.3° F. and the relative humidity 62.0 percent, there were 21.3 percent 

 infected or decayed squashes and the shrinkage in weight was 9.2 percent. In two 

 other storages heat was employed only to avoid freezing. In one of these with the 

 average temperature and humidity respectively 44.4° and 72.4 percent, decay and 

 shrinkage were respectively 4.1 and 9.4 percent; while in another with average 

 temperature and humidity at 44.4° and 83.9 percent, decay and shrinkage were 

 respectively 14.3 and 7.3 percent. 



Miscellaneous Tests and Experiments. (E. F. Guba and C. J. Gilgut, Wal- 

 tham.) 



1. Control of the Begonia Leaf Nematode {Aphelenchoides fragariae). All 

 stages of the nematode in the leaves are killed in water of a mean temperature 

 of 115° F. (5 minutes), 117J^°F. (3 minutes), 118H°F. (2 minutes), and 120i^°F. 

 (1 minute). Submersion of plants in water at temperatures of 121-120° F. for 

 1 minute, 119-117° F. for 2 minutes, or 118-115° F. for 3 minutes, is recommended 

 for infested stock, and the eradicative treatment should be made not nearer than 



