During the winter of 2000-01 we periodically sampled a stand of undisturbed corn stubble for surviving southwestern corn borers, Diatraea grandiosella Dyar. The previous fall this stand had nearly 100% of the plants girdled (cut off 5 to 15 cm above the ground) and most of the crowns (stem bases) contained diapausing corn borers. The larvae were collected and held for moth emergence to verify viability. In November 91% of the crowns had corn borer larvae and 84% of them were viable. By March and April only 10 to 20% of the crowns had corn borer larvae and 40 to 50% of them were viable. In May only 3% of the crowns had corn borer larvae and half of them were viable. In the final sample there were larvae in only 1% of the plants and survival was about 50%. The winter of 2000-01 was a relatively hard winter, but there was still some survival of southwestern corn borers and they are expected to recover and reach economic populations by the second generation. Over the past 20 years in this area there have been two winters that were hard enough to suppress southwestern corn borers for several years.
Species 1: Lepidoptera Crambidae Diatraea grandiosella (southwestern corn borer)
Keywords: diapause
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA