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$3,505,532.60 from stinking-smut infection in tlie state's wheat crop. 

 This loss represents sHghtly more than 4.26 per cent of the total value of 

 the wheat crop harvested in 1923. 



Field observations on the amount of stinking smut in varieties of 

 wheat commonly grown in Illinois as shown in Table 13 indicate that 

 soft wheats are more susceptible to smut infection than the hard winter 

 wheats. 



When stinking-smut infection is present in wheat, several methods 

 are available for preventing its appearance in succeeding years. These 

 methods include change of seed, crop rotation, and seed treatment. Change 

 of seed is often effective if care is taken to see that the new seed is not 

 infected with stinking-smut spores. Crop rotation is useful in reducing 

 the amount of infective material in the soil. Seed treatment, however, is 

 by far the most effective means of control. Infection resulting from 

 spores in the soil is usually slight. The greatest amount of infection 

 comes from spores carried on the seed. If these seed-borne spores are 

 killed very little smut infection will be found in the succeeding crop. 



Three methods of seed treatment, or seed disinfection, are in com- 

 mon use : ( 1 ) Formaldehyde in the proportion of 1 pint to 50 bushels 

 of seed is sprayed over the seed, the whole throughly mixed and covered 

 for five hours. (2) Copper-sulfate solution in the proportion of 1 pound 

 of blueslone to 10 gallons of water is also used. The seed is dipped in 

 this solution, thoroughly wetted, and then dried. Both the formaldehyde 

 and copper-sulfate treatments, though effective, are attended with diffi- 

 culties in the using, and if not carefully handled are apt to cause some 

 injury to the seed. 



More recently there has come into use (3) the copper-carbonate 

 dust treatment, in which copper-carbonate powder is thoroughly mixed 

 with the seed at the rate of 2 ounces per bushel. This dry treatment may 

 be applied at any time before planting. It does not materially injure the 

 seed and may be depended upon to reduce stinking-snnit infection to a 

 minimum. 



A more consistent use of seed treatment throughout our state is 

 greatly to be desired. In the past it has been the custom of growers to 

 wait until serious losses occurred before using preventive measures. A 

 consistent program of seed treatment employed each year will not only 

 obviate the necessity for special efforts, but will also prevent the constant 

 loss from light infections that occurs each year. 



Loose Smut 

 Caused by Ustilago tiitici (Pers.) Rostr. 



.\nother smut disease of wheat occurring in Illinois is loosr siiiiit. 

 This is more generally distributed throughout the individual fields of the 

 state than stinking smut, but is, on the whole, nnich less abundant. ' It 

 is known throughout the state as "smut," "loose snuit." and "black head." 



