ARTIFICIAL INFECTION—FIELD EXPERIMENTS. 31 
Experiments on Mr. Banks’s place—The field offered for experi- 
mental use was on a slope south of the house. Like the Lynch field, 
one had contained a rank growth and the other a thin stand of wheat; 
but the rank growth was denser and the thin growth was poorer than 
that found on Mr. Lynch’s place. In order to balance matters the 
bean plot set out in the dense growth of wheat was used for artificial 
infection, while that in the thin growth served as a check. It was 
noticed that diseased chinch bugs were present in all parts of the 
field before any fungus had been distributed. The first inoculation 
was made May 18. Cultures were mixed with the earth and sown as 
in the Lynch field. The beans were useless, as they were shaded by 
the wheat. The ground was moist in both plots, and especially in the 
treated one. Observations were taken May 25. Both plots, as well 
as the remainder of the field, contained diseased bugs, but the dense 
growth showed the greatest number, outside the plot as well as in- 
side. Had not the Lynch field served as a kind of control these 
results might have been regarded in part as favorable to artificial in- 
fection. On the same date (May 25) a second distribution of fungus 
was made in this plot. Final observations were taken June 12, but 
there was no change in the results. The favorable conditions of shade 
and moisture favored Sporotrichum. No matter whether fungus 
spores were added or not, about the same number of bugs died, and 
there were more than in a plot where the sun had a better access to 
the soil and where conditions were drier. The fungus showed no 
tendency to spread. The bugs had begun to migrate into the neigh- 
boring oats and the cornfields. A wheat field about a fourth of a mile 
distant, untreated, contained many diseased bugs. Other check fields 
were the Cann place and the Ruggles place, both about 3 miles dis- 
tant. Diseased bugs were plentiful in all of them. 
Weather conditions.—Statistics as to humidity and precipitation 
for the district around Wellington were kindly gathered by Mr. 
BK. O. G. Kelly and his associate, the former an assistant in the Bu- 
reau of Entomology of the United States Department of Agriculture. 
The recording instruments were kept at the station, which was 
approximately the center of the area that would include the three 
experimental fields. Observations covered most of May and June, 
during which field investigations were going on. Total precipitation 
recorded by Mr. Kelly, 6.13 inches. The total for April, May, and 
June at Rome, a few miles south, was 6.27 inches. 
The spring and early summer were unusually dry, as the average 
monthly rainfall for the district around Rome was lower than the 
normal by the following amounts: April, 1.59 inches; May, 1.23 
inches; and June, 3.32 inches. In spite of the diminished precipita- 
tion, however, spontaneous outbreaks of Sporotrichum occurred all 
about Wellington, no field containing chinch bugs failing to exhibit 
the whitened, fungus-covered bugs. 
10944°—Bull. 107—11—_—-3 
