MONTANA INSECT PESTS, 1949 AND 1950 



11 



this type, feather bunchgrass becomes more abundant, forming 

 dominant stands. On deep clay soils at lower elevations where 

 subsoil moisture is present, stands of silver sage (Artemesia cana) 

 and greasewood (Sarcohatus vermiculatus) occur. 



From the standpoint of grazing value, the communities dom- 

 inated by western wheatgrass and needle-and-thread western 

 wheatgrass are of greatest importance. Representative areas of 

 both of these types were selected for study in an area which had 

 been sprayed with approximately 1-/3 ounces of aldrin per acre 

 to control grasshoppers and in a comparable unsprayed area. The 

 percentage of ground cover of the various plant species in each 

 community was determined by the point method of analysis. The 

 percentage of ground cover for the western wheatgrass type is 

 given below. 



WESTERN WHEATGRASS TYPE 



Name of Species 



Agropyron smithii 

 Bouteloua gracilis 

 Bromus japonicus 

 Festuca octoflora 

 Koeleria cristata 

 Poa secunda 



Schedoiinardus paniculatus 

 Stipa comata 

 Stipa viridula 

 Astragalus sp. 

 Artemesia jrigida 

 Draha nemorsa 

 Eurotia lanata 

 Gaura coccinea 

 Lactiica sp. 

 Lappula occidentalis 

 Lepidium densiflorum 

 Leucocrinum montanum 

 Malvastrum coccineum 

 Opuntia polyacantha 

 Phlox hoodii 

 Plantago purshii 

 Taraxactim officinalis 

 Tragopogon pratensis 

 Vicia americana 



Total Density 



Percentage of Ground Cover 

 Sprayed Area Unsprayed Area 



11.9 

 0.1 

 0.9 



0.5 



0.1 

 0.8 

 0.5 

 0.2 

 0.2 



0.1 

 0.1 

 0.3 

 0.6 

 0.1 

 1.0 



1.1 

 0.2 

 0.2 

 0.8 

 0.7 



20.0 



9.3 



0.5 

 2.4 

 0.1 

 0.1 

 1.0 

 1.2 

 0.2 



0.6 

 0.1 



0.3 



0.1 

 0.6 



1.0 



0.1 



17.6 



