Resistance of 12 yellow and 12 bronze chrysanthemum cultivars to the European com borer, Ostrinia nubilalis (Hubner), was evaluated in laboratory studies. Yellow cultivars ‘Freedom’, ‘Classic’, ‘Compatriot’, and ‘Fortune’ and bronze cultivar ‘Pancho’ had significantly lower infestation percentages. In field monitoring of chrysanthemum grown in commercial nurseries, the cultivar ‘Fireside Cushion’ was significantly lower at both nurseries, with cultivars ‘Buckeye’, ‘Grenadine’, and ‘Viking’ also having significantly lower infestation percentages. A significant positive correlation between infestation levels and stem diameters indicated stem thickness may be an indicator of host plant resistance.
2Associate Professor and Agric. Research Scientist, resp.