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COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA-CHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA, ILLINOIS 



INSECT WEED & PLANT DISEASE SURVEY BULLETIN 



STATE/COUNTY/LOCAL GROUPS/US. DEPARTMENT OF AGRICULTURE COOPERATING 



FOR IMMEDIATE RELEASE 



No. 13, June 15, 1973 



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

 plant disease situation (fruit and commercial vegetables excepted) 3 along with 

 suggested, abbreviated, control measures. Each individual should check his own 

 fields to determine local conditions. 



INSECTS 



CORN INSECTS 



Black cutworm problem calls were not as prevelant this week as last. Occasional 



fields in the southern half of Illinois are infested, but the overall damage is 



light. Fields that showed damage prior to June 1 incurred little additional damage 



this past week. Damage is generally confined to the low areas in fields. 



Corn fields should continue to be watched closely for cutworm damage for another 

 week. The hot weather will encourage cutworms to feed at or below the soil line, 

 rather than cutting above the growing point as was observed earlier. Plants cut be- 

 low the growing point will not recover. 



If most worms are less than 1-1/2 inches and you find 5 to 10 percent of the plants 

 being cut, apply controls immediately. For control, broadcast 20 pounds of 5-percent 

 carbaryl (Sevin) bait per acre. A spray of 2 pounds of carbaryl and 2 quarts of mo- 

 lasses plus water per acre banded at the base of the plants is also effective. Com- 

 mercially prepared spray baits containing carbaryl plus Tractum or molasses are avail- 

 able. Trichlorfon (Dylox) at 1 pound per acre as a spray will control black cutworms. 

 Use 20 gallons of water per acre when band- spraying with trichlorfon, then cultivate 

 in order to throw soil over this band in the row. 



JUN 2 5 1973 



If replanting is necessary and if the majority of the cutworms are once more of small 

 size (less than 1-1/2 inches), they could seriously damage the new planting. In that 

 case, apply 5-percent carbaryl (Sevin) bait at 10 pounds per acre as a band over the 

 row behind the press wheel when planting. If most of the worms are 1-1/2 to 1-3/4 

 inches or larger, the corn can be replanted without using an insecticide treatment. 



First-generation European corn borer moth emergence is complete in southern and cen- 

 tral Illinois, and egg-laying and egg-hatch have begun. An occasional field that was 

 planted early in west-central Illinois, particularly in bottom land areas, now has 

 as many as 200 egg masses per 100 plants. These fields should be observed closely 

 during the next seven to ten days. Some of these fields may require control measures 

 during the week of June 25. In general, corn borer survival will be low in most fields 

 since the development of the corn plants is much later than normal, except in the 

 fields mentioned. 



