MONTANA EXPERIMENT STATION. 241 



pans and getting covered with oil jump out again but these are in- 

 variably killed. The back of the pan is extended vertically by means 

 of a strip of cloth or canvas supported by upright stakes. See Figure 

 lo. In large fields several hopper-dozers are sometimes attached in 

 series by means of a long pole and drawn by two horses, one at each 

 end of the pole. IVo horses attached in this way are much better 

 than one in the middle of the pole because they tend to gather in the 

 grasshoppers rather than drive them away. 



The Artificial Use of Diseases. — Under such conditions as occur 

 on the Montana ranges, where the greater part of the injury by grass- 

 hoppers has been done, the artificial use of deadly diseases is an at- 

 tractive subject. It we were able to propagate and distribute a 

 disease which would be communicated from one insect to another 

 and so extended ovei large areas, the solution of the grasshopper 

 problem would be reached. Various experimenters in the United 

 States have made careful tests of such diseases but thus far very few 

 encouraging results have been secured. 



Realizing that the artificial use of diseases, though offering 

 small hope of success, constituted the only hope, the Experiment 

 Station through this department made a careful test of what has 

 been called the South African grasshopper fungus disease. A sin- 

 gle tube of this disease from Africa was very kindly given me by 

 Prof. C. P. Gillette of Fort Collins, Colorado. Cultures on potato 

 were made and distributed to about 300 applicants in the state. We 

 also made careful laboratory tests on caged grasshoppers of various 

 species, but so far as we are informed not one grasshopper was kill- 

 ed either in the field or laboratory test. The various other entomolo- 

 gists also failed to get results of decided value. We feel, therefore, 

 that until something entirel}^ new in the form of a disease is known, 

 we will still have to wait for Nature to take her course, except where 

 it is possible, in restricted areas, to use some of the other remedies. 



CRIDDEL MIXTURE. 



The substance known by this name has lately come into favor 

 as a grasshopper remedy in some parts of the United States. It 

 was first brought to public attention by Dr. James Fletcher, govern- 

 ment entomologist of Canada, who, at the meeting of official entomo- 



