48 CIRCULAR 849, U. S. DEPT. OF AGRICULTURE 



predators was devised. Without doubt, however, buds and preda- 

 ceous beetles consume a great many cutworm larvae. A farmer in 

 western Kansas reported that migrating hawks, descending on a 

 field infested with pale western cutworms, practically eliminated 

 them within a few hours. During outbreaks of the army cutworm 

 large flocks of crows were seen in infested fields. Two crows were 

 shot, and an examination of the stomach contents showed many 

 fragments of army cutworm larvae. 



Predaceous beetles consume large numbers of cutworms and army- 

 worms, but no quantitative field records have been made. However, 

 one specimen of Calosoma lugubre Lee. in captivity, offered full- 

 grown larvae of the corn earworm, consumed 16 before indicating 

 a loss of interest. The records of parasitism and disease given in 

 this circular show that most species of cutworms and armyworms 

 are subject to attack by natural enemies. Even larvae of subter- 

 ranean habit do not escape. Instances were observed where outbreaks 

 of both surface and subterranean forms were brought under control 

 by a devastating disease, which rapidly reduced the larval populations. 



Chemical Control 



With the exception of the subterranean and boring groups, which 

 are controllable only by cultural methods, most species of cutworms 

 and armyworms can be checked with poison bait. The recommended 

 formula for poison bran bait is as follows: 



Bran 100 pounds. 



Paris green, white arsenic, or sodium fluosilicate 4 pounds. 



Water 10 to 12 gallons. 



The finished bait should crumble easily when compressed in the hand. 

 In infested areas the bait is broadcast evenly at the rate of about 15 

 pounds (dry weight) per acre. 



CAUTION. — The poisons used in baits for cutworms and armyworms are 

 also poisonous to animals and man. Keep children, poultry, pets, or livestock 

 from gaining access to the poison or to the receptacles containing the poisoned 

 bait or used in mixing it. Clean thoroughly all utensils immediately after being 

 used. Broadcast any surplus bait thinly on the ground in a field. 



If the larvae are almost mature, results from the use of poison 

 bait may be disappointing. It is therefore important to determine 

 whether the larvae are still actively feeding when the bait is dis- 

 tributed. In many cutworm infestations the damage is frequently 

 done before control measures can be applied. This is largely because 

 the larvae consume most of their food during the last two larval 

 instars and the feeding by the earlier instars is not noticeable. For 

 this reason growers should maintain a close watch in order to detect 

 large populations of young larvae and apply control measures before 

 damage becomes serious. 



Cultural Control 



In the central Great Plains, where there are outbreaks of the pale 

 western cutworm, the author {20) found that the damage to wheat 

 could be minimized by the use of summer fallow. This method of 

 control consists of alternating wheat culture and summer fallow. 



