18 MONTANA EXPERIMENT STATION BULLETIN 474 



caused by the tightly curled sheaths holding the head in the boot 

 were noted in most cases. The procedure of keeping summer fallow 

 free from volunteer wheat, barley, and grasses to prevent a source 

 of infestation the following year was practiced in most cases. 



ENGLISH GRAIN APHID (Macrosiphum granariuni) 



The English grain aphid was not reported in 1949, but was 



reported in Flathead, Ravalli, and Mineral counties in 1950. These 



infestations were localized in nature, not covering large areas, 



and in general did not warrant control beyond cultural measures. 



SPRING GRAIN APHID (Toxoptera grmninum > 

 The spring grain aphid, or greenbug, was not reported in 1949, 

 and occurred in only small localized areas in Sheridan County in 

 1950. Control beyond cultural measures was not warranted. 



SAY'S STINK BUG (Chlorochroa sayi) 



Say's stink bug was reported in localized areas in Hill County 

 in 1949, and in Rosebud and Hill counties in 1950. This sucking 

 insect if numerous enough is capable of causing damage to grain. 

 It is generally found in economic populations in weedy abandoned 

 lands. Non-economic populations can be found in nearly every part 

 of the stale that is under cultivation. 



WHEAT STEM SAWFLY (Cephus cinctus) 

 The wheat stem sawfly infestation in 1949 dropped to very low 

 levels in the more severe areas. This was probably due to the late 

 wet spring and the resulting late thin crop. In 1950 a marked in- 

 crease in infestations was noted. Because losses were small in 

 1949, a tendency to shift from Rescue wheat probably contributed 

 to the increased losses. It should be noted, however, that in 1950 

 Rescue wheat did not stand up to its usual performance. Infest- 

 ations as high as 40% were recorded. The resistance of Rescue 

 wheat is controlled in part by weather conditions, and the 1950 

 season was the type that reduces its resistance. 



The partial failure of Rescue points to the need for better 

 resistant varieties and a determined effort is now being made by 

 various agencies to develop these varieties. The State Entomologist, 

 in cooperation with the departments of Agronomy and Soils and 

 Zoology and Entomology of the Montana Agricultural Experiment 

 Station, and the bureaus of Entomology and Plant Quarantine 

 and Plant Industry, Soils, and Agricultural Engineering of the 

 United States Department of Agriculture are taking the lead in 

 this endeavor. During the past two seasons more than 5,000 

 varieties of wheat, a large part of the world collection, have had 

 preliminary testing and more are in the process of testing. These 

 include both spring and winter types. It is hoped that out of these 

 new types of wheat, resistance may be found that can be bred 

 into commercially acceptable varieties. 



