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COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA-CHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA, ILLINOIS 



MSECT WEED & PLANT DISEASE SURVEY BULLETIN 



WE/COUNTY/LOCAL GBOUPS/U.S. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 9, June 1, 1972 



This series of weekly bulletins provides a general look at the insect, weed, and plant 

 disease situation (fruit and commercial vegetables excepted) , along with suggested, 



i. F £cu;h individual should check his own fields to deter- 



abbreviated, control measjxr^s. 

 mine local conditions. 



JUN U 1S72 



INSECTS 



CORN INSECTS 



UNl •£**>- ■ I or ILLINOIS 

 AT URBANA-CHAMPAIGN 



Many reports of black cutworms damaging corn in the southern half of Illinois were re- 

 ceived this week. Continue to watch the corn for cutworm damage in the northern half 

 of Illinois. Infestations there are still possible. The worms are now reaching ma- 

 turity, will soon stop feeding, and will then pupate in most of these problem fields. 

 A full-grown, black cutworm larva is about 2 inches long. 



If stands are severely damaged and corn is to be replanted, check the size of the 

 worms. If most of the worms are 1-1/2 to 1-3/4 inches or larger, the corn can be 

 replanted without the use of an insecticide. By the time the corn germinates and 

 emerges, the cutworms will have pupated. On the other hand, if most of the worms 

 are 3/4 of an inch to 1-1/4 inches, they will feed for another seven to ten days and 

 could seriously injure the new planting. In this case, apply the 5-percent carbaryl 

 (Sevin) , apple-pomace bait at 10 pounds per acre as a band over the row when planting. 

 A spray of 2 pounds per acre of carbaryl with molasses (Sevimol) or with an attractant 

 (Tractum) sprayed over the row two or three days after planting could be used in place 

 of the carbaryl, apple-pomace bait. 



To protect stands from further damage by cutworms apply the 5-percent carbaiyl (Sevin) , 

 apple-pomace bait at 20 pounds per acre, broadcast. A spray of 2 pounds of actual 

 carbaryl per acre with molasses (Sevimol) or with an attractant (Tractum) , directed 

 at the base of the plant, will also control cutworms. In addition, trichlorfon (Dy- 

 lox) is effective, applied at 1 pound per acre in at least 20 gallons of water as a 

 spray directed at the base of the plants. Cover the trichlorfon spray band by throw- 

 ing soil at the base of the plants with a cultivator. 



Garden symphlans or garden centipedes have damaged two fields of corn in the center 

 third of Illinois according to a report we received. Damage from this pest is dif- 

 ficult to diagnose. Undoubtedly, many fields sustaining only light damage go unde- 

 tected each year. These are small critters (about 1/16 to 1/4 of an inch) . They are 

 white and have many legs, move rapidly in the soil, and attack the roots. They prefer 

 the root hairs and tender new roots , but they will reduce the root system to a stub 

 if the infestation is severe. Infested plants are stunted, turn purple, and may wilt 

 and die. These pests feed throughout the season, moving closer to the surface when 

 conditions are moist and going deeper at dry times. 



