BIENNIAL REPORT 



OF THE 



Illinois State Laboratory 



OP 



NATURAL HISTORY 



To the Trustees of the University of Illinois. 



Gentlemen: The operations of the State Laboratory of Natural History 

 diu'ing the past two years have been carried successfully forward along the 

 customary lines of investigation, with a notable expansion, under the stimulus 

 of appropriations made bj^ the last legislature, in the study of the contagious 

 diseases of insects and in the work of the Illinois River Biological Experiment 

 Station. 



The insect-disease work took during the summer of 1895 the direction of an 

 investigation of the causes of our general failure in field experiments with 

 white muscardine of the chinch-bug, together with an investigation of a newly 

 discovered disease of the common squash-bug. Among additional subjects 

 studied, was a destructive disease of grasshoppers in the West, material for 

 which was obtained from a correspondent in Colorado, and the so-called white 

 plague of the common cabbage worm. 



The general residt of our studies of the white museaixline has been to dis- 

 credit still further the practical utility of that disease for field operations on a 

 large scale. In consequence of this outcome very few distributions of in- 

 fected material have been made from my office during 1896, and those only in 

 response to direct requests from farmers. The material sent out has been 

 accompanied, as in all my previous sendings, with explicit warning to the 

 effect that no definite reliance Avas to be placed on it, but that its use was to 

 be regarded as an experiment only. It now seems quite clear, as the general 

 result of all our investigations of this complicated subject, that the ciix-um- 

 stances under which artificial field infection of chinch-bugs with the white- 

 muscardine fungus will take practical effect in a way to produce any important 

 benefit are at least so rare and unusual that the whole subject must at present 

 be assigned to the limbo of unverified theories. 



A mbre promising result was obtained from an investigation of a bacterial 

 disease of the common squash-bug, which proved to be highly contagious and 



