First-generation 

 population 



Percentage of fields expected to have 

 second-generation populations in the 

 following numbers: b orers/100 stalks 



Section 



borers/100 



stalks 



0-150 



150-300 



300-500 



500+ 



Northwest 



L7 





67 



21 



9 



5 



Northeast 



7 





79 



16 



4 



1 



West 



L2 





75 



17 







2 



Central 



3 





84 



14 



2 



o 



East 



4 





83 



15 



2 







West -Southwest 



5 





SO 



16 



3 



J 



East -Southeast 



2 





90 



9 



1 







Southeast 



2 





90 



9 



1 



o 



These are predicted figures from 10-year averages; the weather, natural enemies, 

 and the percentage of first-generation worms that develop into second-generation 

 moths (some first-generation larvae will not pupate until next spring) , could still 

 change the picture. 



Wooly bear or yellow bear caterpillars are abundant in some cornfields. These 

 light yellow- to -white or brown, hairy caterpillars are chewing off silks, similar 

 to a scissors cut. The silks are usually cut at the level of the ear husks. The 

 caterpillars seldom eat completely down the silk to the ear tip, as do the root- 

 worm adults. Silks will usually regrow and be pollinated, although pollination 

 may not be as complete. 



Most worms are an inch or more long; some are already mature (about 1 1/2 to 2 

 inches) and pupating. When mature, the worms spina silken- lined cocoon covered 

 with their body hairs. Fields just now silking are the ones to watch. In general, 

 control is seldom of great value. If silk feeding is severe and the caterpillars 

 are numerous, treatment may be justified. Apply 1 1/2 pounds of carbaryl (Sevin) 

 or toxaphene per acre for control. Toxaphene should be used only if the corn is 

 to be used for grain. Toxaphene -treated com should not be fed as forage to dairy 

 cattle or to li\ r estock being fattened for slaughter. Treatments applied after the 

 90-percent silk stage are of little benefit. 



Fall armyworms are present in some late-maturing cornfields. These brown to dull- 

 green smooth-skinnedworms feed in the whorl, giving plants a ragged appearance as 

 the leaves emerge. Before applying control measures, be sure the worms are still 

 present and that most of them are not more than an inch long. When they reach 

 about 1 1/4 inches, they are about mature; at that size, they stop feeding, drop 

 to the ground, enter the soil, and pupate. For control, apply either 1 1/2 pounds 

 per acre of actual carbaryl or toxaphene as granules. Toxaphene granules should 

 be used only if the corn is to be used as grain; it should not be used on ensilage 

 corn. 



Armyworms can be found in grassy areas in northern sections. As many as 4 to 20 

 armyworms per square foot were reported from one area this week. The worms are 

 still small; damage is not yet apparent. Grassy cornfields should be watched for 

 the presence of this insect. If needed, carbaryl (Sevin) at 1 1/2 pounds of actual 

 insecticide per acre, as a spray, will give adequate control. Toxaphene at 1 1/2 

 pounds actual per acre can also be used- -but only on corn grown for grain, not on 

 ensilage corn. 



