TWENTY-THIRD REPORT OF STATE ENTOMOLOGIST 11 



across country and had done some damat^e. In previous years serious 

 trouble from tliis insect lias occurred only west of the continental 

 divide. 



THE RED-BACKED CUTWORM 



Huxoa ocliiDgasttr Ciucrr. 



This widely distributed cutworm has been prevalent in Montana 

 during the past two years. In 1929, sugar lieets south of ^Manhattan 

 were seriously daniaged at about thinning time, the damage ])ecoming 

 noticeable after thinning when the worms concentrated on the plants 

 that were left for the crop, thereby seriously reducing the stand. In 

 lht' liitter Root \'all('\- a more serious and more extensive damage was 

 done both in 1929 ami ID.'SO. In the vii-inity of Helena this cutworm 

 also attacked sugar beets. It is one of the common cutworms of the 

 garden iniil li.is at times been injurious to barley. 



THE PALE WESTERN CUTWORM 

 Porosagrotis orthogonia Morr. 



Doctor Cook, formerly of this staff, has shown that the pale 

 western cutworm appears as a pest in "cycles," that is, under certain 

 climatic conditions in the State, such as a rainfall from May 1 to 

 July 31 of less than four inches, it may increase to destructive num- 

 bers. From his weather records in ^lontana he had predicl^^f^that the 

 pale western cutworm would bt> on the increase in 1929 in certain re- 

 gions in INIontana. In .Iiuie. 1!».!(). Doctor Cook made a field survey to 

 determine the extent of danuige. In general the prediction was vej'i- 

 fied. Damage had occurred in fields near Ilarlowton, Square Butte, 

 and north of Willow Crek. If dry weather continues during the next 

 few years, it may be expected that very severe damage will be done 

 by this insect, particularly in wheat fields. 



A bulletin embodying the results of the field studies has been 

 issued by the Experiment Station and is available for research 

 workers. The Extension Service has ])ublished a bulletin giving 

 control methods, which is for popular distribution. 



THE ALFALFA-SEED CHALCIS-FLY 



Bruchopliagus funebris How. 



This minute insect feeds in the individual alfalfa seeds and is 

 capable of doing damage ranging to as high as 50 or 60 per cent. 

 The insects do not feed or mature on stored seeds, but develop in 



