Fig 1.— Symptoms of smut on mature onions. A. Showing distorted leaves with ruptured pustules 

 exposing black spore powder. B. Smut pustules on bulb. C. Healthy onion for comparison. 

 Note failure of diseased plants to develop normal bulbs. 



■A, i--~Jf 



Fig. 2. — Formaldehyde treatment for smut. 2 rows in center received no formaldehyde. 



