34 MASSACHUSETTS HORTICULTURAL SOCIETY. 



Discussion. 



W. D. Philbiick asked whether Professor Halsted had ever used 

 extremely diluted Sulphate of Copper, — oue ounce of the sulphate 

 to one hundred gallons of water? 



Professor Halsted answered that he had no doubt that the 

 proportions named would be useful in many cases. He said that 

 fungicides were frequently used too strong, as experimenters found 

 to their cost. He had an acre of plants on which to experiment. 

 In his trials upon beans he used Bordeaux Mixture of three 

 degrees of strength. The full strength kept off the fungi, and 

 the leaves retained a good color, but the plants were stunted in 

 growth, attaining no more than half the usual size of the variety. 

 With the strength reduced one-half, the good effects were quite as 

 evident, but the dwarfing was still considerable. Recluced to one- 

 quarter of standard strength, the mixture thoroughly protected the 

 plants from fungous injury, but still prevented full development. 

 This trial showed conclusively that fungicides are generally used 

 too strong ; next year still weaker solutions will be tried. Fungous 

 spores will not germinate in water in which even a small quantity 

 of copper filings have been kept, and this without any sulphuric 

 acid, or any other corroding agent, than the supposed pure water 

 contained. The greatest success with fungicides is secured when 

 they are put in the right place at the right time. 



Charles J. Dawson inquired what should be done to prevent 

 " damping off" in the seed pan. 



Professor Halsted replied that while the question is an important 

 one, the attention of the station officers had not been so specially 

 called to it as to many others, and therefore but little is as yet 

 known about it. He did not see why the soil should not be 

 sprayed as well as plants ; nor why hot water could not be used — 

 not so hot as to endanger the plants, but sufficiently so to kill the 

 fungous threads, which cannot endure a very warm bath. He knew 

 that young ferns had been so treated successfully. He suggested 

 that possibly Bordeaux Mixture, if sufficiently reduced in strength, 

 might prove more advantageous. 



Jackson Dawson said lie had tried some chemicals but was more 

 successful with (piite hot sand. Still, he thought seedlings could be 

 saved quite as well by washing out the soil in which they were 

 started, and pricking them out in purified soil. 



