114 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



are ordinarily free from these parasites, but when the marching 

 habit is assumed the flies swarm around them on cloudy days 

 and before the next year they again have the remnants of the 

 voracious army under subjection. Therefore, worms with the 

 tachina-fly eggs on them (Fig. 95) should never be destroyed 

 where avoidable. 



Control. When detected, all efforts should be centred on 

 keeping the worms out of crops not yet attacked and confining 

 their injury to as small an area as possible. As a barrier to their 

 progress, there is nothing better than a dust furrow made as 

 already described for chinch-bugs (p. 92), two or three of which 

 may be found necessary in cool weather or where a fine dust can- 

 not be maintained 



Deep fall plowing and thorough harrowing will be effective 

 against the hibernating larvae, as will the burning of all grass 

 along ditches, fences, and spots where the larvae normally live. 



By thorough spraying, or perhaps better by dusting, a strip 

 of the crop with Paris green or some arsenical, and liberally 

 distributing poisoned bran mash (see p. 57), large numbers 

 may be destroyed. Where they are massed in furrows they 

 may be destroyed by spraying them with pure kerosene or crude 

 petroleum. 



As in fighting chinch-bugs the army worm must be given 

 immediate and conclusive combat if the loss of crops is to be 

 prevented, for they move rapidly and destroy all in their path, 



The Fall Army Worm or Grass Worm * 



Though somewhat the same in its habits as the true army- 

 worm, the Fall Army Worm is so called because it appears later 

 in the season, the former species being rarely injurious after 

 August 1st. It is also more omnivorous, for while the army- 

 worm prefers grasses, and grains, the fall army-worm feeds 

 upon a large variety of crops, including sugar-beets, cow-peas, 

 millet, sweet potatoes, and many other forage and truck crops. 

 In Nebraska and the Central West it is a serious pest of alfalfa 

 and is called the Alfalfa Worm. It is also sometimes very de- 



* Laphygma frugiperda S. and A. Family Noctuidce. See Farmers' Bulletin 

 752, U. S. Dept. of Agriculture. Walton and Luginbill. 



