1999 Sweet Corn Variety Trial: Fresh-Market Varieties

By Eric Burkness, Department of Entomology, University of Minnesota

By Eric Burkness, Scientist, Dept. of Entomology, University of Minnesota In 1999, 14 fresh-market sweet corn varieties were evaluated for susceptibility to European corn borer (ECB) and corn earworm (CEW), and overall ear quality. A replicated trial was conducted at the Rosemount Experiment Station, Rosemount, MN (Dakota Co.). Plots were planted on June 17, 1999. Plots were harvested over 3 dates based on days to maturity for each specific variety (see Table 1). On each harvest date, 10 ears were harvested from each of 4 replications for a total of 40 ears for each variety. Ears were evaluated for ECB, CEW, feeding damage, and yield. It is important to note for this study that no insecticides were applied to plots.

Results indicate no significant differences between varieties with regard to infestations of ECB or CEW (Table 1). However, varieties that were harvested later in the season had higher numbers of ECB and CEW in each ear. This is most likely to be a reflection of the ear being available for a longer period of time for infestations and/or damage to occur. For CEW, the numerical increase in ear infestations is due to the migration of CEW adults into Minnesota during the 3rd week of August. Therefore, early-maturing varieties were harvested before the heaviest migration of CEW. The higher level of feeding damage present on each ear of the later harvested varieties is indicative of the increased presence of CEW. Likewise, the percent of marketable ears dropped with later harvest dates (Table 1). Significant differences in yield were present between varieties. However, this is likely due to differences in ear length and cob diameter rather than an influence of insect infestations.

All varieties exhibited good to excellent taste. Rust was present in all varieties at low levels and with the exception of ‘Sugar buns’, no smut was observed. All varieties had good kernel fill on the tip of the ear, except ‘Incredible’.

The varieties tested exhibited good fresh-market qualities and there were no consistent differences in the level of ECB or CEW infestations. The level of ECB and CEW infestation is more dependant on planting and harvest date. Earlier planted sweet corn has the benefit of avoiding the late season migration of CEW and should minimize exposure of the ear to second generation ECB. This evaluation also indicates the importance of monitoring fields for both ECB and CEW activity, including the use of black light and pheromone traps, respectively, to aid in determining insecticide applications.

For more information visit the Minnesota Extension Service's Sweet Corn page.

Co-Editors:Bill Hutchison, Department of Entomology, University of Minnesota, hutch002@tc.umn.edu
Jeanne Ciborowski, IPM Program, Minnesota Department of Agriculture, jeanne.ciborowski@state.mn.us
Cindy Tong, Department of Horticulture, University of Minnesota, ctong@extension.umn.edu
Production Editor: Suzanne Wold, Research Specialist, University of Minnesota, woldx018@tc.umn.edu

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Last Revised May 4, 2000.
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