4 MONTANA EXPERIMENT STATION BULLETIN 526 



We have accomplished much along the lines of grain sanitation since 

 the Food and Drug reports show Montana wheat to be relatively free 

 of obnoxious contaminants. 



Goatweed continues to pose a threat to valuable rangeland in 

 western Montana. Although this weed can be controlled by chemical 

 means, inaccessibility of infestations rules out this method in many 

 cases. In 1948 the first importations of Chrysolina gemcllata and C. 

 hyperici, the goatweed beetle which feeds exclusively on goatweed, 

 were made into the state. Since that time other colonies have been 

 brought in and many transfers from established colonies of beetles 

 have been made. Control of the weed has been accomplished in some 

 areas and in others evidence of control is becoming apparent. Another 

 insect enemy of goatweed was brought into the state in 1954 and 

 1955 to hasten control of this noxious weed. Unlike the Chrysolina 

 species which feed on the leaves and buds, the new insect is a root 

 borer. It has worked very well under conditions unfavorable for 

 Chrysolina and should prove an important addition to our beneficial 

 insect fauna. 



RANGELAND GRASSHOPPER RESEARCH 



Studies of grasshoppers inhabiting Montana rangelands have been 

 continued during the past biennium in cooperation with the Montana 

 Agricultural Experiment Station and Montana State College. 



The primary objectives of the rangeland grasshopper research 

 in Montana are the prevention of outbreaks and the minimizing of 

 significant annual losses in forage. It is realized that grasshoppers 

 are an integral part of the grassland environment in which they live 

 and as such are subjected to the numerous, complex, and interrelated 

 forces of that environment. Therefore, an attempt is being made to 

 study these environmental forces and to determine how they affect the 

 biology and behavior of the various grasshopper species present. " 



Factors affecting grasshopper distribution and abundance are 

 being determined through studies of the direct and indirect effects 

 of such things as the composition of the vegetation (i.e., kinds and 

 abundance of plants), the amount of foliage cover (i.e., bare ground 

 and plant litter), land management practices, and weather. The cause 

 of fluctuations in grasshopper numbers is being attacked by studying 

 such things as the presence of specific food-plants, general plant 

 composition, and ground cover on grasshopper population changes. 

 Behavior patterns of the various species which include feeding habits, 

 local movements, migratory tendencies, and selection of egg laying 

 sites are being studied. 



During the past biennium considerable emphasis has been placed 

 on the measurement of the amount of seasonal damage done to range- 



