106 BOARD OF AGRICULTURE. [Pul). Doc. 



in the right position in the soil, sufficiently near the surface 

 to get air, moisture and warmth, it will grow. If buried too 

 deep, it will not grow. I had supposed that these spores 

 were similar, and that slowly the resting spores of the onion 

 would lose their capacity to injure later onion crops. They 

 would not all lose this capacity the first year, some the first 

 year and some later. I would like the speaker to give the 

 audience his opinion. 



Dr. STUK(iis. It is a perfectly impossible question to 

 answer, simply because there are no experiments, so far as I 

 know, to show whether an onion spore will germinate apart 

 from the presence of an onion plant. Land may lie fallow 

 or be plowed successively for different crops year after year 

 for six, seven or ten years, and yet reproduce onion smut the 

 eleventh year in as large a degree as it did the first year. 

 This w^ould indicate that the process of destruction must at 

 any rate be an extremely slow one, and one which we cer- 

 tainly cannot count upon for practical results. 



Professor Brooks. Is it not easy to understand that that 

 might be the case, when we consider the enormous number 

 of these spores? We know it takes a great many years to 

 get rid of a weed, and we must remember that the number 

 of weed seeds as compared to the numljer of spores is small. 



Mr. Geo. P. Sjiith (of Sunderland). What is the nature 

 of the spore that causes the blight of the onion ? 



Dr. Sturgis. There is a regular mildew of the onion, 

 something like the mildew of potatoes. There is also an- 

 other trouble, which looks something like mildew, that is 

 caused by a very minute insect of the genus thrips. There 

 are a number of fungous diseases, and it is hard to tell what 

 one is meant by the term "blight." If I could know the 

 appearance of the diseased plant, I might be able to say more 

 about it. 



Mr. S. R. Maynard (of Berlin). How many gallons of 

 Bordeaux mixture are required to spray an acre of potatoes 

 if the tops are well grown ? 



Dr. Sturgis. I cannot answer from memory. I should 

 say that between sixty and seventy gallons of Bordeaux mix- 

 ture would spray an acre of potatoes pretty well. 



The Chairmax. Perhaps Mr. Kirkland could give us 

 some information in this line. 



