In this issue:
Corn earworm
| Vol. 1 No. 2 | August 26, 1999 |
Corn earworm - Watch Continues
Corn earworm (CEW) moth catch remains high in many southern Minnesota locations, with several traps exceeding 75-100 moths/night (see graph). This is the time of year (Aug. 25th plus/minus 5 days) that we get major new flights of CEW into the upper midwest. The CEW moths are believed to originate from the southern cotton/corn producing states, e.g., from Texas high-plains where field corn is drying down. Egg hatch will not occur quite as fast as it did when temperatures were reaching 90F, but current average temperatures (and above avg. humidity) are very conducive to egg lay, continued egg hatch and larval survivorship. Egg lay continues at our Rosemount research site.
Sweet corn in fresh-silk stage (first to early brown silks) should be protected with insecticide applications. Again, the more recent pyrethroids, Baythroid, Capture and Warrior are likely to provide the best residual activity. With the CEW pressure we have, these materials should still provide adequate control on a 5-7 day schedule (5-day for fresh market; 7-day for processing). As more data become available, these recommended intervals may change. Pounce/Ambush can also be used but will have slightly less residual activity than the new pyrethroids. Once silks start turning brown, or if the corn is within 7 days of harvest, additional sprays are not warranted.
Co-Editors: Bill Hutchison, Department of Entomology,
University of Minnesota
Jeanne Ciborowski, IPM Program, Minnesota Department of Agriculture
Production Editor: Rebecca Hines, Research Associate, University of
Minnesota
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Last Revised August 22, 2002.
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