INSECT 

 SURVEY 





THE LiBRABY OF THt % 



M 



BULLETIN jun ifcm^ 



College of Agriculture ^ pj [UMS 



University of Illinois ' 



and Natural History Survey, Urbana, Illinois 



itate / County / Local Groups 



FOR IMMEDIATE RELEASE 



U. S. Department of Agriculture Cooperating 



May 31, 1968 



ILLINOIS INSECT, DISEASE, AN D WEED SURVEY BULLETIN NO. 12 



This series of weekly bulletins provides a general look at the insect, -plant dis- 

 ease, and weed situation (fruit and commercial vegetables excepted) , along with 

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

 fields to determine local conditions. 



INSECTS 



Corn Insects 



Corn seed insects continue to destroy stands of newly emerging corn. Some fields 

 being destroyed for a second time will need to be replanted again. Circumstantial 

 evidence indicates that both the seed corn beetles and maggot are resistant to the 

 chlorinated hydrocarbon insecticides in these problem fields . How widespread this 

 resistance may be has not been determined as yet, but several dozen fields are 

 known to have problems. 



Preliminary observations in test plots (replanted and treated a week ago) indicate 

 that the organic phosphate insecticides used for control of resistant rootworms 

 will effectively control corn seed beetles. For the present, if replanting be- 

 comes necessary, we suggest applying 1 pound of actual diazinon per acre as a band 

 on the soil surface just ahead of the press wheel. Take time to consider before 

 disking -up a reasonably good stand- -it might still produce more corn than a later 

 planting . 



Corn rootworm eggs will be hatching soon. Resistance by northern corn rootworms 

 to aldrin and heptachlor has become widespread in the northern half of the state. 

 The western corn rootworm, which is highly resistant to these same insecticides, 

 will cause commercial damage in some fields in the area west of a line from Galena 

 to Dixon to Peoria to Carthage. Potentially, any field planted to corn for 3 or 

 more years (in some cases even second-year corn may be affected) in the northern 

 half of the state could have moderate-to-severe lodging from rootworm attack this 

 summer. 



If you suspect or know that you have resistant rootworms and if you did not use 

 an organic phosphate or carbamate insecticide at planting time, apply an organic 

 phosphate insecticide within the next two weeks. Use granules applied at the 

 base of the plants, and cover them by cultivation. Diazinon, disulfoton (Di- 

 Syston) , or phorate (Thimet) at 1 pound of actual chemical per acre have label 

 approval and are suggested for use. If you have not yet planted your corn and 

 wish to control rootworms, apply diazinon, Dyfonate, BUX-ten, Dasanit, or phorate 

 as granules at 1 pound of actual chemical per acre in a 7 -inch wide band lust 



IHE LIBRARY OF THI 



JUii 3 u.,, 



UNIVERSITY OF ILLINOIS* 



