48 EXPERIMENT STATION. [Jan, 



Onion Smut. 



BY G. E. STONE. 



Onion smut is known to be a verv formidable disease in cer- 

 tain sections of the United States, in some localities onion 

 growing having been abandoned on account of its prevalence. 

 It has not occurred so seriouslv in the Coimecticut vallev in 

 this State, where a large i)roportion of our onions are grown. 



Onion smut has been known in J^Iassachusetts for many years, 

 Mr. Benjamin P. Ware having referred to the injury caused Iw 

 it in the Massachusetts State Board of Agriculture report for 

 18G9 and 1870. The disease appears to be on the increase now 

 in the Connecticut valley and onion growers are making efforts 

 to combat it. It is known that the critical period for infection 

 occurs in the early or seedling stage of the plants, and for this 

 reason onion " sets " are immune to the disease. The smut on 

 the young plants forms dark-colored or sooty masses, and on the 

 older, mature specimens it is very conspicuous. Since infection 

 takes place in the early stages of the seedlings, any method which 

 will kill the smut spores which happen to be attached to the 

 seed or are dormant in the soil will prove beneficial. The for- 

 malin treatment is cheap and efficient, niid when smut is trou- 

 blesome this remedy should be applied. 



The past year we have devised a simple and inexpensive 

 formalin drip which can easily be attached to any onion sower, 

 treating the seed in the drills. The tank which carries the 

 formalin is made of copper, although other metal will answer 

 as well, and the one we have constructed for our purpose is 12 

 inches long and 7 inches high and holds 1 gallon. It can be 

 made larger if necessary, and it is so simple that any tinsmith 

 can construct it. It has an opening at the top, with a cover, 

 and a flexible block tin tube provided with a wheel valve is at- 

 tached to tli<' biittoiii :iiid I'ciiiilatos the flow of tlio foviiialin (see 



