Cold temperatures and heavy rains have killed many corn seedlings, says University of Illinois Extension crop specialist Emerson Nafziger, and stands less than 15,000/acre will benefit from replanting. He says slow growth is not good either, and with this year’s poor weather, replanting is “favored” this year. http://www.ipm.uiuc.edu/bulletin/article.php?id=942
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Replanting decisions need to include insecticide considerations, adds University of Illinois Extension entomologist Kevin Steffey. He says if you may have already applied the maximum amount of one insecticide, you should not violate federal label regulations. But he says consider other insecticides. http://www.ipm.uiuc.edu/bulletin/article.php?id=938.

Cold soil delayed corn germination and it is delaying corn rootworm arrival also. Typically they hatch in last week of May, but they may be hatching in the first two weeks of June, as they did in 1996-1997. Illinois Extension entomologists say that implies:

1) Early planting and a late hatch puts increased pressure on soil insecticide performance.
2) Early planting of Bt corn followed by a very late hatch could mean more root injury.
3) Late hatch and late planting may simply delay emergence and corn tasseling.
4) This may increase the odds that these events occur during the hottest summer period.