SIXTEENTH ANNUAL KEPORT OF STATE ENTOMOLOGIST ol 



It is too early to state how serious this pest may become but 

 it is certainly serious, and rather extensive damage was done this 

 year. Further studies on this insect are to be made next year if it 

 is present. 



THE SUGAR-BEET WEBWiORM 



Ah outbreak of small striped caterpillars appeared about the 

 10th of August throughout the major part of the State east of the 

 continental divide. Letters and telegrams came in rapidly from 

 farmers and county agents. While no great amount of damage, 

 excepting in gardens, was finally done, the fact that the caterpillars 

 were generally scattered throughout grain fields, where they were 

 feeding on weeds, caused much uneasiness among the farmers who 

 feared that when the weeds were gone the grain would be attacked. 

 The insects continued in abundance for about ten days. The species 

 concerned was found to be one which has been known as the sugar- 

 beet webworm {Loxostege sticticalis L.). This insect is a very 

 general feeder. During this season it was reported on corn, cab- 

 bage, beets, alfalfa, gooseberry, and currant bushes, among cultivated 

 plants, but weeds were particularly mentioned and the Russian 

 thistle standing in grain crops was often spoken of. In view of the 

 shortage of hay and other feeds for stock in some parts of the State 

 some farmers were planning to cut Russian thistle as feed but were 

 prevented by the insects which ate down this weed completely. Pig- 

 weed (Chenopodiuin) , is a favorite also, and spinach, onions, celery, 

 and tomatoes have been mentioned by other writers as being food 

 plants. 



These caterpillars w^ere present in incredible numbers. They 

 moved about to some extent and devoured the vegetation as they 

 advanced. It was reported repeatedly that they were "eating every- 

 thing green." It was also reported to us that they had stopped 

 railway trains, which is entirely possible and would be due to the 

 crushing of their bodies on the rails, thereby making such a slippery 

 track that the locomotives could not pull the trains. Circular 43 

 of this station (June, 1914), entitled "The Sugar-beet Webworm" 

 by J. R. Parker w^as sent out very generally and the remedies pro- 

 posed were effective. 



It is not necessarily true that this insect will return next season. 

 Parasites are very efifective in its control and judging by past 



