]() MONTANA EXPEEIMENT STATION Bui. 133 



were the cause of the disappea^-ance of the grasshopper. It is noted 

 now that these parasitic flies are not present in connection with 

 the outbreaks of the three grasshoppers listed above as injurious 

 in 1919. We look upon this as indicating that the grasshopper diffi- 

 culty will be continued through several years. 



SUGAR-BEET WEBWORM 

 The common name, sugar-beet webworm, is not a satisfactory 

 one for the insect {Loxostege sticticalis Linn.) which in recent years 

 has been unusually abundant and has caused general apprehension 

 among farmers and gardeners. During the season of 1919 this 

 insect occurred in large numbers, though probably not quite as 

 abundantly as during the preceding year, and was the occasion of 

 a considerable amount of correspondence ari^^ing over the central 

 and northern portions of Montana. There were two broods, the 

 first appearing in May and early June and the second mainly in 

 August. The injury done was chiefly to garden plants and to the 

 Russian thistle. The presence of large numbers of this insect in 

 grain fields, feeding on the Russian thistle, caused the farmers to 

 become anxious in many cases and they wrote to us for information 

 regarding what might be expected. It was feared that they would 

 attack the grain when the Russian thistles were all gone. Experience 

 has indicated that this webworm does not attack wheat and we 

 were able to assure the farmers that no damage would be done. 

 In some cases farmers were afraid to plant a new crop of grain 

 because they knew that this insect was still in the soil from the 

 preceding year, appearing there as larvae in long silken tubes, ver- 

 tically placed in the soil. A number of letters were written to such 

 farmers. Real injury, however, was done in gardens where beets, 

 spinach, and a few other plants were eaten. This insect is capable 

 of doing extensive damage in sugar beet fields. 



ALFALFA 

 The alfalfa weevil {Phytonoirmis jjosticiis Gyll.), which attracted 

 the attention of the residents of Utah in the year 1904 and has 

 spread and caused extensive loss to growers of alfalfa and stockmen 

 in that state, has continued to spread to the northward. This very 

 injurious insect has in a relatively brief time extended into parts 

 of three states by direct spreading and during the same time has 

 made two jumps, one into Colorado and another into western Idaho, 



