COLLEGE OF 

 AGRICULTURE 

 UNIVERSITY OF 

 ILLINOIS AT 

 URBANA-CHAMPAIGN 

 AND NATURAL 

 HISTORY SURVEY 

 URBANA, ILLINOIS 



MSECT. WEED & PL ANT DISEASE SURVEY BULLETIN 



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



FOR IMMEDIATE RELEASE 



No. 21, December 



1970 



SPECIAL ISSUE 



INSECT RECOMMENDATIONS FOR FIELD CROPS 



We receive many inquiries about changes in suggested uses for insecticides before our 

 recommendations are published in January. We are sending you these Tentative Sugges- 

 tions and Major Changes for 1971 to help answer such questions. Caution statements, 

 time limitations between application and harvest, and other precautions are not in- 

 cluded . 



These tentative suggestions will appear in final form in University of Illinois College 

 of Agriculture Circular 899, which will be sent to the printer by December 10. 



This release was delayed this year waiting for the final decision on certain label clear- 

 ances. Minor changes are anticipated. These suggestions are only tentative. 



CHANGES IN THE SUGGESTIONS FROM 1970 



Aldrin and heptachlor . We did not recommend the use of aldrin or heptachlor in 1970 as 

 soil insecticides for corn fields urging that all existing supplies be used up. For 

 1971, we are advising against the use of aldrin or heptachlor as soil insecticides for 

 corn. In arriving at this decision, we considered: 



1. The frequency of damage by those soil-inhabiting pests still controlled by aldrin 

 and heptachlor, and the abundance of such pests in corn fields. These insecticides 

 no longer give practical control of wireworms, seed-corn beetles, or seed-corn mag- 

 gots. 



2. The fact that wireworm populations in fields planted to corn in regular rotations 

 are generally low. The profitable use of either aldrin or heptachlor would be most 

 likely on first-year corn, following established grass or clover sods. The insecti- 

 cide would be broadcast at 1.5 pounds per acre and disked- in prior to planting. 

 Wireworms and white grubs might be a problem in such a situation, and aldrin or 

 heptachlor would be helpful as control agents. 



5. The previous history of use in Illinois. This indicates that in the approximately 

 5 million acres that will be planted to corn, residues of dieldrin-aldrin or hep- 

 tachlor epoxide-heptachlor now present may exert a depressing effect on the general 

 pest population to the extent that continued applications would not be advisable. 



4. The difficulty encountered in selecting fields that would warrant the use of aldrin 

 or heptachlor. This creates problems. A few hundred thousand acres of corn could 

 be profitably treated if aldrin or heptachlor were applied broadcast for the con- 

 trol of black cutworms. But these fields cannot be selected until damage has oc- 

 curred, which is after planting. Therefore, to prevent this damage, it would be 



THE USRARY - 



DEC 14- 1970 



UNIVEKSITY Of ILLINOIS 



