Twelfth Report op the State Entomologist 211 



parasite, Smicra albifrons (Walsh). Ophion purgatum Say, is one of its 

 larger parasites, and in some localities it is often quite abundant. In 

 Minnesota its cocoons were numerous in the infested fields the past year. 

 The following species are also recorded among its parasites : Ichneumon 

 Uiicanice Yitchznd I. Jlavizonatiis Cress., Hemiteles laticinctus Riley MS., 

 Stibeiitcs gentilis Cress., Limneria oxylits Cress., Mesochorus scituliis 

 Cress., and Rhogas terminaUs Cress. Bassi/s scutellaris Cress, was ob- 

 served apparently ovipositing on the army- worm. 



Preventives and Remedies. 



When a field has become badly infested with half-grown army-worms, 

 httle can be done to save the crop beyond cutting at once what remains 

 and promptly removing it from the field. In order to prevent injuries 

 by this insect, the intelligent farmer will, so far as possible, combat it 

 along two lines. In the first place he will endeavor to prevent it breed- 

 ing in numbers in his fields by so cultivating and caring for his crops as 

 to offer the least favorable conditions for hibernation, oviposition, and 

 the subsequent growth and development of the caterpillars. Secondly he 

 will make effort to protect and favor its natural enemies. 



Destruction of hibernating forms. — Whether the insect passes the 

 winter as a moth or a caterpillar is not so very important to the farmer, 

 provided he can destroy them in either state. In nature both the moths 

 and caterpillars shelter themselves largely under thick grass and rubbish 

 as winter approaches. The burning over of such places late in the 

 autumn or preferably in the early spring must result in the destruction of 

 large numbers of the insects. This measure would at the same time kill 

 many other injurious insects hibernating in such places, and also, unfort- 

 unately, some beneficial forms. It is believed, however, that the benefit 

 resulting from the burning would far outweigh the loss caused by the 

 destruction of our insect friends. 



Proper cultivation. — It has been shown in the preceding pages that the 

 moth exhibits a decided preference for thick herbage of some kind when 

 about to deposit her eggs, and that such areas are distributing centers to 

 other portions of the infested fields. Many such places are to be found 

 in the neglected weeds and grasses springing up beside fences, or they 

 may occur in the middle of fields, as the result of unequal manuring. 

 The good farmer by keeping his entire fields clean, and avoiding uneven 

 manuring, will not oflTer conditions that invite oviposition. 



