44 THE WHITE-FUNGUS DISEASE IN KANSAS. 
of the infection resulted. While diseased chinch bugs were used to 
some extent in artificial infection, they proved inadequate because of - 
the small amount of fungus available. Spore material for field work 
was generally obtained from cultures grown on a mixture of corn 
meal and potato extract. By the use of this medium large quanti- 
ties of fungus were propagated in the laboratory. Its spores were 
tested from time to time in order to be assured of their power to 
produce disease in living chinch bugs. 
With the exception of the experimental fields in one county 
(Anderson) there was already an abundance of Sporotrichum na- 
turally present in the soil, as manifested by the whitened carcasses of 
its victims. These were generally in such large numbers and were so 
widely distributed that it seemed utterly futile to add any more 
fungus, since it was such a trifle by comparison. Nevertheless, 19 ex- 
perimental fields, distributed over 5 different sections of the State, 
were treated with Sporotrichum spores. In some the artificial in- 
fection was confined to small plots of wheat 50 feet square, with the 
expectation that the intensive infection would start an epidemic of 
the disease that would spread and kill a large proportion of the 
bugs. But no results were forthcoming, for not only did the plots 
fail to become centers of contagion, but there was little or no ap- 
preciable difference between the treated and the untreated, or check 
plots, which were always used as a basis of comparison. General 
field infections were likewise always failures, 
Considering the 19 localities as a whole, there were all sorts of 
conditions of humidity and rainfall, also character of soil. The 
results, however, were always the same—never at best any more than 
a slightly appreciable effect due to sowing spores and never more 
than a small percentage of the bugs killed. The bugs victimized by 
the fungus were as numerous in an untreated plot or field as in a 
treated one, the numbers bearing no relation whatever to artificial 
infection, but rather to climatic conditions, shade, moisture, ete. 
The evidence in every instance was overwhelming against the arti- 
ficial use of fungus, as being without effect, and hence useless, since 
the fungus naturally found in the soil really accomplished whatever 
destruction of chinch bugs there was. 
The third problem to be solved was the practicability of artificially 
treating a field with Sporotrichum when the fungus was shown to 
be scarce or, at least, ineffective. Three fields—one at Garnett, the 
others at Colony—were of this sort, and the bugs in all of them were 
liberally dosed with fungus. Small areas were treated as well as 
entire fields, and diseased bugs were used as well as culturally grown 
fungus; but scarcely any effect could be made, as measured by mor- 
tality among the bugs. No epidemic could be started nor the death 
rate appreciably increased, even in marked spots that were given 
specially large amounts of infection. 
