Resistance of Cucumber Varieties to Tetranychus urticae: Genetic and Environmental Determinants123

The “nonbitter” cucumber variety ‘Marketmore 72’ and the “bitter” varieties ‘Marketmore 70’, ‘Tablegreen 65’, ‘Hawaiian’, and ‘Marketeer’ were tested for resistance to the twospotted spider mite. When bitter varieties were gorwn in the same flats, Hawaiian exhibited the most pronounced resistance. Water stress caused a significant increase in the resistance of bitter varieties but did not affect resistance of the nonbitter variety. Resistance was not attributable to behavioral avoidance of bitter leaves.