Apparent resistance of a treatment cv. as influenced by different surrounding cv. was measured in screening cucumbers for resistance to cucumber beetles and pickleworms. Degree and frequency of seedling damage, and percent seedling reduction were greater when ‘Zucchini Elite’ squash was the surrounding cv. than when any of 3 cucumbers were the surrounding cv. Significant differences in damage to seedlings were found among 9 cucumber cv. Two non-bitter cucumbers were among those least damaged by cucumber beetles; however, the frequency and degree of damage as measured by cotyledon feeding did not differ significantly from 1 of the bitter cv. Factors other than cucurbitacin content are probably involved in expressions of resistance to cucumber beetle. The surrounding cv. had no effect on pickleworm infestation. Pickleworm infestation was low in all cucumber cv. (1.4 per 100 fruit) when compared to summer squash (78 per 100 fruit). The value of ‘Zucchini Elite’ squash as a trap crop for pickleworm may be outweighed by the increased damage to seedling cucumbers by cucumber beetles when squash is the surrounding cv.
Received for publication March 3, 1971. Paper No. 3704 of the Journal Series of the North Carolina State University Agricultural Experiment Station, Raleigh.
Associate Professor, Department of Horticultural Science.
The author gratefully acknowledges the technical assistance of R. R. Horton, Department of Horticultural Science.