150 EXPERIMENT STATION RECORD. 



rate the bugs, although they had been in very large numbers before, 

 had disappeared, and in consequence of this fact fewer requests for 

 boxes of spores were received. The author seems to deprecate this 

 latter fact, since it seems to show that the farmers seldom think of apply- 

 ing for remedies until the insects have become very injurious. During 

 1896 the climatic conditions were such that the chinch-bug disease 

 worked with entire satisfaction wherever it was conscientiously tried, 

 and some 1,233 farmers were supplied with boxes of spores. But in 

 spite of the apparent success the author questions whether the fungus 

 always kills the bug, and states that the more he and his assistant work 

 with the fungus the less certain they feel that it is a remedy always to 

 be relied upon. 



During the summer and early autumn numerous complaints of insect 

 depredation were received from various portions of the State. Upon 

 investigation, the depredations were found to be caused by the frit fly 

 (Oscinis soror), which was damaging wheat fields. The wheat stem 

 maggot {Meromyza americana) was found to have appeared again in 

 destructive numbers, which threaten the crops of small grain in the 

 future. Experiments to determine whether this insect has many para- 

 sites showed that the latter are not sufficiently numerous to promise 

 much future assistance, and the only remedy that farmers can rely upon 

 seems to be systematic rotation of crops. The Hessian fly (Cecidomyia 

 destructor) caused considerable losses in Minnesota for the first time, 

 but parasites of the insect were so numerous and active in some places 

 that most of the flies have been destroyed. Among the parasites 

 Merisus destructor, Eupelmus allynii, and Polygnotus hiemalis are men- 

 tioned. The army worm (Leucania unipuncta) was also very injurious, 

 and during July and August many gloomy accounts of it and the ruin 

 it threatened appeared in the newspapers. All portions of the State 

 were infested, even the unsettled region of the extreme north. Near 

 Northtield the worms covered an area of from 4 to 5 square miles, and 

 occurred in scattered patches over the country as far as 20 miles in 

 all directions. In some cases ditches were dug about uninfected fields, 

 with the usual good results. The worms were found to be attacked by 

 several parasites, some 60 per cent of those examined being found to 

 contain the maggot of tachinid flies or parasitic wasps. Among these 

 parasites were found the tachinid, Exorista leucanice, and the hymenop- 

 tera, Apanteles congregatus and Ophion purgatum. But the best friends 

 of the farmer, the author thinks, are such animals as the shrew, skunk, 

 weasel, and gopher, which devour the worms in large numbers. 



The erratic army worm [Noctua fennica) was also numerous, and in 

 some cases its presence was painfully evident, since no living green 

 thing was left untouched. Even the bark of young poplars, willows, 

 cherries, and sumacs was eaten. An examination of the worms resulted 

 in finding but few parasites; in fact, only one species was found, viz, 

 Meteorus vulgaris. Two species of white grubs (Lachnosterna tristis 

 and L. rugosa) were very numerous and did considerable damage. The 



