23 



COMPARATIVE SURVEY OF THE INFECTION EXPERIMENTS CARRIED ON WITH THE LOOSE 



SMUT OP WHEAT. 



A. INFECTION EXPERIMENTS IN 1903. 

 I. BLOSSOM INFECTION. 



1. On a hot day, the 19th of July, 1902, wheat heads in (ull bloom were infected in a blossoming 

 wheat field in Grabschen. The smut was taken fresh from the same field and was Introduced into 

 separate blossoms by means of a brush. Blossoms insuflJciently developed were removed. In the next 

 year there developed from the harvested seed 



220 stalks, 67.7 per cent of which were smutted. 

 The control field of the same wheat taken in 1902 from a field free from smut showed no smut. 



2. Blossoming bearded wheat in another field was infected in the same way. From the seed 

 harvested 



80 stalks developed which contained 66 per cent smutted ones. 



II. CYLINDER INFECTION. 



1. June 1, 1902, soon after a thunderstorm, cylinder infection with fresh smut from the same field 

 was made in three different parts of a blooming wheat field in Leerbeutel. From the sterilized seed 

 in place 1, 520 stalks were produced, of which 39.1 per cent were smutted. 



2, 549 " " " " " 37.5 



3, 216 " " 11.6 



On an average, 29.4 per cent of the stalks were smutted. 



The control field, with about 1,000 plants from non-infected seed of the same field, had only two 

 smutted stalks in 500. 



III. INFECTION OP THE SEED. 



1. Wheat from Miinster was mixed with smut spores from the same field and sown. Out of 



300 stalks developed there, none were smutted. 

 The control from sterilized seed of this same field had 2 smutted specimens. 



2. Wheat from Leerbeutel mixed with smut spores from Miinster furnished 



280 stalks with 2 smutted specimens, as did the control also. 



3. Wheat from Leerbeutel mixed with smut spores from the same field gave 



250 stalks and 3 smutted examples. 

 In the control, one smutted stalk was found. 



4. Wheat from Schlanstedt mixed with smut spores from the same field gave 



310 healthy stalks, as did the control also. 



IV. INFECTION OF THE SUBSTRATUM. 



1. Sterilized horse manure was infected with pure smut spores from the wheat field in Miinster, 

 by spraying with an atomizer, and was then mixed with two parts of compost. Wheat from Schlan- 

 stedt was sown in the soil thus treated. 



Out of 250 stalks started in germinating cases and later transplanted into the open ground, not 

 one was smutted. 



2. Smut spores from Miinster were mixed with compost and wheat from Schlandstedt was sown 

 on this substratum. 



Out of 250 stalks none were smutted. 



3. The same experiments was carried out as in 1 and 2 with wheat from Leerbeutel, and smut 

 spores from the same wheat field. This lot, as well as the control, had 3 per cent of smutted stalks. 



B. INFECTION EXPERIMENTS IN 1904. 

 1. BLOSSOM INFECTION. 



1. Single blossoms of suitable heads were infected in a blooming wheat field in Grabschen with 

 fresh dry smut of the same wheat, in two separate places. 



The sterilized grains were planted in March, 1904, on sterilized sand from the river Oder, in closed 

 germinating cases and transplanted, in April to open ground. 

 The grains harvested from place 1 grew 



93 stalks, 31 per cent of which were smutted. 

 Those harvested from place 2, 



120 stalks, with 58 per cent smutted. 



