safest of the four to use; carbaryl is the most -dangerous one to use around the 

 bees . 



CORN 



Black cutworm damage is still slight, and we are uncertain about activity by this 

 pest. They cannot be written off yet as a potential problem. Five reports of 

 damage thus far involved (1) no treatment; (2) aldrin, broadcast; and (3) failures of 

 aldrin, diazinon, and phorate (Thimet) as band or row treatments. Broadcasting al- 

 drin usually controls cutworms, as does diazinon on late-planted corn. However, 

 aldrin and phorate applied in the row will not provide satisfactory control. 



Corn that was planted early can be severely damaged. When cutworms slice off the 

 plants below the growing point the plant dies . This happens when the corn approaches 

 12 inches in height. Thus, stands of early corn could be hurt now by cutworms, but 

 corn planted recently or that being planted now may escape damage for at least 

 another two weeks. Mien corn is cut off above the heart, the plant keeps right on 

 growing- -in fact, may not even be slowed down. However, a late infestation of black 

 cutworms in mid-June, as we had in 1958, could be devastating to all corn. 



If damage appears, use a spray- -directed at the base of the plants --of carbaryl 

 (Sevin) at 2 or 5 pounds, diazinon at 2 pounds, toxaphene at 3 pounds, or trichlor- 

 fon (Dylox) at 1 pound of actual chemical per acre. It is best to use at least 20 

 gallons of water per acre, and to cover the spray band by throwing soil at the base 

 of the plants with a cultivator. 



Common stalk borers attack corn alongside fence rows, grass waterways, and ditch 

 banks , where they have overwintered as eggs . Mien the wo mis outgrow the grass or 

 weed stems or the fence row is mowed, the borers migrate into the adjacent corn rows. 

 Sometimes, an attack on young plants by the borers will wilt the plant; other times, 

 will fail to produce an ear, even if it lives. These striped worms with a dark- 

 purple band around their middle can be controlled by a spray of carbaryl (Sevin) as 

 they migrate. It is too late to spray once they are in the corn plant and leaf 

 ragging is apparent. Control is justified only in severe infestations. 



European corn borer pupation and emergence is a little earlier than usual, but the 

 moths may concentrate in fields that were planted early to lay their eggs. Such 

 fields can be found in most areas, and may suffer severe first -generation borer 

 damage. However, any weather conditions that would delay the emergence of the 

 moths and egg-laying could change this situation, increasing the possibility of 

 a greater infestation. 



The pupation of overwintering corn borer is complete in southern Illinois, where 

 the moths are flying and egg- laying is well underway. Pupation is almost complete 

 in central Illinois, moth emergence has begun, and egg-laying will start soon. In 

 northern Illinois, pupation is progressing rapidly, but no moth emergence has been 

 noted as yet. 



The egg-laying period is usually about three weeks. Insecticides to control first- 

 generation corn borers should not be applied to field corn until almost all eggs 

 have hatched. Thus insecticide applications are usually made about three weeks after 

 egg- laying begins. 



If corn is 50 inches tall (leaves extended) or more at that time and if 75 percent 

 or more of the plants show any fresh whorl feeding, apply carbaryl (Sevin) or diaz- 

 inon as granules . 





