ARTIFICIAL INFECTION—-FIELD EXPERIMENTS. 33 
fungus naturally present in the soil. In analyzing the factors, the 
distribution of the dead bugs was taken to be the important element. 
A search of the field showed that they were thicker in some parts than 
in others, but numbers were related to conditions of moisture rather 
than to centers of artificial infection. Hence it is not improbable that 
the situation would not have been appreciably altered had no fungus 
been sown in the field. Other fields near Lebanon in which no Sporo- 
trichum had been introduced, or at least not until a later date, were 
used as checks, and particularly the Moore field, 1 mile south, and the 
Waddles field, 1 mile north. They were examined carefully on the 
same dates as the Sargent field, and at no time was there any percep- - 
tible difference, so far as diseased bugs were concerned, in the three 
fields. All the check fields contained diseased bugs in considerable 
numbers, especially where the conditions were particularly favorable. 
Owing to artificial infection of the Sargent field before the time was 
ripe for a general spontaneous outbreak of Sporotrichum, the occur- 
rence of the outbreak in this field had all the appearance of being due 
to the sowing of the fungus. Toa casual observer the success of arti- 
ficial infection would have been regarded as indisputable, though of 
course partial, since not all the chinch bugs were killed. It is likely 
that some of the “successes” reported by farmers in former years 
were due to a misinterpretation of such appearances of Sporotrichum 
among the bugs. 
The results of the experiments at Lebanon showed the importance 
of moisture conditions as factors in the development of the Sporo- 
trichum disease, especially in a dry season, and at the same time 
how unimportant a factor is the sowing of the fungus spores. 
Total precipitation at Lebanon for the months of April, May, and 
June, 1910, 6.85 inches, which was 2.08 inches less than the average. 
For May, however, the rainfall was 0.04 inch greater than the aver- 
age. The greatest deficiency in precipitation was during April. 
Southeastern section, Montgomery County, Cherryvale—Three 
farmers near Cherryvale kindly offered the use of their wheat fields 
for experimentation. They were Mr. Metcalf, Mr. Benham, and Mr. 
Darling. The vicinity of Cherryvale was badly infested with bugs 
and hence offered a favorable opportunity for experiment. The east- 
ern portion of the State, moreover, exhibited better climatic condi- 
tions, owing to greater rainfall and humidity. 
On April 27 collection of bugs and earth in sterile jars was made 
from each of the three fields mentioned above. Sporotrichum de- 
veloped readily, thus showing the presence of the fungus naturally in 
the soil. On the Benham and Darling places, 50-foot plots of the 
usual type were set out to cowpeas and placed about 100 yards apart. 
The cowpeas did not prove of any advantage as to shade, and so 
the plots were used to mark the areas for infection and check, 
