18 MONTANA EXPERIMENT STATION BULLETIN 425 



may shed light on the causes of the fluctuations, and it will prob- 

 ably be necessary to discover these causes in order to make pre- 

 dictions. Second, it makes possible prompt warning of the location 

 of threatening populations. An attempt is made to make the sur- 

 vey sufficiently early each year to enable farmers to use control 

 measures where needed. 



FLEA BEETLES (Epitrix spp.) .—Interest has arisen in these 

 pests due to the recent separation of a new species from this com- 

 plex group by L. G. Gentner of the Oregon Agricultural Experi- 

 ment Station. This species, E. tuberis Gentner, is a much more 

 injurious form than others in the west because of the habit of 

 the larvae of boring into potato tubers. A large series of these 

 insects were submitted to Mr. Gentner, who stated that the great 

 majority of them were the common E. subcrinita Lee, a species 

 commonly found on potato, tomato, radish, turnip, and cabbage 

 leaves in Montana. There were no specimens of the tuber flea 

 beetle present in the collections, but unexpectedly one specimen 

 of E. cucumeris Har. appeared in a collection from potatoes at 

 Laurel, July 2, 1941. This is the first record of this species in 

 Montana, although the species is common in other parts of the 

 country. 



WHEAT INSECTS 



HESSIAN FLY. (Phytophaga destructor Say.).— The first record 

 of this insect in Montana was reported in the Twentieth Report 

 of the State Entomologist in 1924, when it appeared in Richland, 

 Roosevelt, Wibaux, and Dawson counties along the eastern bor- 

 der of the State. During that season some fields suffered losses as 

 high as 30 percent. It did not again appear until 1930 when spe- 

 cimens were sent in from Baker in Fallon County. 



During the summer of 1944 the attention of this office was 

 again called to the presence of the Hessian fly in the State. Inves- 

 tigation disclosed its presence in an area, roughly, from Valley to 

 Custer county and east. Its appearance was spotty, and injury up 

 to 20 percent was reported for some spots in certain fields. Over 

 the area as a whole, however, the injury was not great, and had 

 it not been for considerable hail damage and resultant close ex- 

 amination of fields by hail adjustors it is probable that the most 

 of the infestations would have gone unnoticed. 



Upon the first notice of this insect in the State twenty years 

 ago this office was considerably concerned about the future spread 

 and activities of this pest. Now, with this two-decade period for 

 observation, it appears that the pest is likely to be only occasion- 

 ally sufficiently abundant to cause noticeable damage. The reasons 

 for its sporadic appearance are not entirely clear. During the past 

 season there was early dry weather during the growing season, 



