5i6 
DONALD REDDICK 
viable spores and mycelium of Fusarium martii phaseoli from culture. 
The fungus, which was supplied through the courtesy of Dr. W. H. 
Burkholder, had been maintained for several months in pure culture 
but the medium (bean-pod decoction agar) was uniform throughout 
the period, and a sub-culture had been made every ten days. 
Pure-line seeds of a pea bean,^ were disinfected externally with a 
I to 1,000 solution of mercuric chlorid, after which they were sprouted 
in a moist chamber. They were planted on January lo, 191 7, six^ 
seeds in each culture. 
When the cotyledons had broken through the ground all plants 
were inoculated with B. radicicola by injecting into the soil about the 
roots one cubic centimeter of a heavily laden water suspension of this 
organism taken from bean nodules, and the number of plants per pot 
was reduced to four. 
After twelve days the plants with soil temperature at 34° were 
developing the first trifoliate leaf; those at 22° had just spread the 
first pair of true leaves and those at 15° were not all through the soil 
surface. On the forty-fifth day the plants at 34° were beginning to 
blossom while those at 22° began blossoming eleven days later. The 
plants at 15° were either dead or very poor and none developed satis- 
factorily. A single one of these cold-soil plants finally reached a 
height of about 15 cm. and produced one blossom but did not set a pod. 
It is to be borne in mind that the air temperature here was practically 
the same as that of the plants with soil temperature of 22°. 
Unfortunately some of the plants in the control cultures became 
infected, the contamination apparently being carried by numerous 
small insects that were abundant on the plants. In the cultures at 
22° five of the twelve plants were diseased and in those at 34° eight of 
the twelve plants were affected. All of these plants were affected 
relatively late as compared with the inoculated plants, so that it is 
impossible to judge what amount of damage may be attributed to the 
^ The seed was supplied through the courtesy of the Department of Plant Breed- 
ing, Cornell University and is maintained under the department number 1986-2. 
^ From the outcome of this experiment and numerous others subsequently 
performed with beans of this and another pure line, and with beans secured on the 
open market, it is very evident that not enough seeds were used at the outset. After 
seeds of uniform size and appearance are selected it is safe to allow for only about 25 
percent as likely to yield plants entirely free from defect and of perfectly uniform 
appearance. Weak plants frequently cannot be detected for ten days or two weeks 
after the plants emerge from the soil. 
