General . We have discontinued recommending aldrin, chlordane, and heptachlor in Il- 

 linois. All three corn rootworm species, seed-corn beetles, seed-corn maggots, and 

 possibly wireworms and white grubs are no longer effectively controlled by these in- 

 secticides. Farmers are cautioned to omit the use of aldrin or heptachlor for one 

 crop year before growing soybeans in a field. Research data indicate that trace 

 amounts of insecticide residues are detectable in soybeans where these insecticides 

 were used the preceding year. The tolerance for residues in soybeans is zero. 



Alfalfa weevil . We encourage alfalfa growers in the southern half of Illinois to 

 consider a fall insecticide -application program in fields where weevils have been 

 a problem. Insecticides applied in early to mid-November kill the adult weevils 

 before they deposit eggs in alfalfa stems in late fall. Best results will occur 

 if the insecticide is applied when the average temperature remains above 45° F. 

 for two days after treatment. Suggestions for fall treatments are listed below. 



Lb. active ingredient per acre 



carbofuran (Furadan 4 Flowable)* .5 



methyl parathion* .5 



Supracide* .5 



azinphosmethyl (Guthion)* .5 



malathion and methoxychlor .75 and .75 



diazinon and methoxychlor (Alfatox) .... .5 and 1 



Imidan 1 



* Should be applied by commercial applicator. 



No-till corn insect complex . No-till corn presents a different set of conditions 

 for insects than does conventionally tilled corn. In no-till corn, insects have 

 a more stable habitat, and this sometimes favors the development of certain pests 

 problems. For example, armyworms, common stalk borers, billbugs, flea beetles, and 

 wireworms are some of the insects that may attack no-till corn planted in grass sod. 

 We have had an opportunity to test some of the soil insecticides on the market. Based 

 on these trials, planting-time treatments of carbofuran (Furadan 10G) at 2 and 3 

 pounds of active ingredient per acre were relatively effective in suppressing damage 

 from armyworms, common stalk borers, billbugs, European corn borers, flea beetles, 

 and wireivorms . Furadan, a systemic insecticide, may be applied as a 7-inch band or 

 placed "in the furrow" with the seed. Our suggestion to Illinois farmers growing 

 no-till corn is to apply Furadan at 2 pounds (20 pounds of 10-percent granules) per 

 acre as a 7 -inch band or in the furrow. As an alternative, the organic phosphates 

 will give reasonable protection against wireworms and white grubs. 



STORED-GRAIN INSECTS 



Sanitation, bin spraying, and grain treatment are the key steps to a successful con- 

 trol program. Malathion is still the mainstay for bin spray and grain -treatment 

 spray since it effectively controls the complex of stored-grain insects with the ex- 

 ception of the Indian meal moth . Resistance of this insect to malathion has become 

 widespread, and we can no longer depend on malathion to control this problem. Di- 

 chlorvos (DDVP) plastic resin strips received registration for use in the overspace 

 of grain bins, including soybeans. Hang one strip per 1,000 cubic feet of over- 

 space about June 1 or at storage. Replace with a new strip in about 8 weeks (mid- 

 August) . These strips effectively prevent Indian meal moth infestations from de- 

 veloping in enclosed bins (metal bins) but may fail to provide effective control 

 in wooden open-top bins. Sealing these latter bins with polyethylene sheeting 

 should allow the dichlorvos strips to perform effectively. 



