28 The Bullethst. 



to the root, and there pass the winter in the full-grown condition, chang- 

 ing to pupse in the spring, from which the moths emerge to lay eggs for 

 the destructive spring brood of worms. 



It must be remembered that no exact dates can be set for the times at 

 which moths will emerge, or eggs be laid, for these will vary with the 

 season and elevation. Thus at Raleigh, in 1913, we found larvae 

 abundant in cornstalks July 1st, and in 1905 we found pupse July 15th 

 in stalks from Johnston County, though in 1902 we bred adult moths 

 July 8th. But it seems fairly well established that normally there are 

 two full broods each season. It is quite likely that some of the worms of 

 the second brood feed on other plants than corn — indeed, in addition 

 to corn and cane, Ainslie says that it has been reported on sorghum, 

 Johnson grass, guinea-corn, and gama grass. 



If each worm simply burrowed once into the stalks and remained 

 inside, the case might not be so serious; but they have the destructive 

 habit of leaving and reentering the stalk again, so that each worm may 

 make several holes. 



REMEDIES. 



Thorough destruction of stalks which have been rendered useless, rem- 

 nants, and stubble, would seem to be the most likely method of con- 

 trol. If infested stalks be cut close to the ground while borers are 

 still in them, and fed green, many of the borers will inevitably be de- 

 stroyed. If the stalks are left standing until the usual time of harvest, 

 and are then cut close to the ground and shredded or made into ensilage, 

 it is to be presumed that some of the second brood will be destroyed. 

 Those left in the stubble can then be reached by plowing out the stubble, 

 raking together and burning. Through the early part of the season (up 

 to about July 1st) stalks which have already been rendered worthless 

 should be pulled and fed green as fast as they are seen to destroy the 

 worms in them, for they have no future value anyway. Our common 

 custom of "pulling" the fodder and allowing the stalks to stand is favor- 

 able to this insect. But if the fodder is to be "pulled," and it is desired 

 to allow the stalks to rot in the field, then if they be plowed under as 

 deeply as possible the adult moths would have difficulty in emerging. 



Next to the destroying of the Borers themselves in the stalks, the later 

 average planting seems to offer the best hope of escape. The data al- 

 ready given indicate that corn planted reasonably late will largely escape 

 injury by the first brood, though it will be exposed to the second brood. 

 Dr. Howard presents results noted in 1891 (in Virginia?), from Avhich 

 the following is given : 



Date of Planting. Per Cent of Damaged Stalls. 



April 1 to 15 25 



April 15 to 28 20 



May 1 to 15 15 



May 15 to 31 12 



June 1 to 15 8, or less. 



