7-5 Report of the Botanist of tub 



In extreme cases they use from two to three times as much 

 seed as would be required on land free from smut. Finally, there 

 comes a time when it is impossible to obtain a " stand " no mat- 

 ter how much seed is used. 



rotation of crops. 



When smut becomes so troublesome that onions can no longer 

 be grown with profit the land is planted to some other crop for 

 two or three seasons. This treatment does not entirely rid the 

 soil of smut but it reduces the amount somewhat so that for a 

 few years following it is again possible to raise onions. In the 

 Orange County onion district corn and potatoes are the crops 

 most commonly used in such a rotation and it is there generally 

 believed that corn is rather the more efficient in removing smut 

 from the soil. Speeding the land down to grass for three or four 

 years is also said to be somewhat beneficial. 



How long it would be necessary to withhold onions from the 

 soil in order that smut might entirely die out is not known, 

 but it would certainly require many years. Some observations 

 made by Dr. Thaxteri in Connecticut bear on this point. A field 

 which had not grown onions for twelve years was sown to onions 

 in 1888 with the result that from 10 to 50 per ct. of the plants 

 became affected with smut. 



While it is true that under some conditions onion smut spores 

 may remain alive in the soil for a period of several years, it is 

 the common experience of onion growers that even an occasional 

 change of the crop for one or two years gives appreciable relief; 

 and it is our belief that a systematic rotation of crops would 

 very considerably- reduce the amount of loss from smut. 



BURYING the SURFACE SOIL. 



Various methods of burying the surface soil have been tried 

 with varying success. One such method is deep plowing. This 

 has sometimes given good results the first season but after that 

 the smut is as bad as ever. Another method is to cover the field 



'Thaxter, R. Ann. Rep. Conn. Agr. Exp. Sta. for 1S89: 138-139. 



