Resistance of impatiens germplasm to western flower thrips feeding damage

Western flower thrips (WFT) [Frankliniella occidentalis (Pergande)] are an ever-present problem in greenhouse floricultural crops. To determine if host plant resistance varied in impatiens [Impatiens wallerana Hook. f.] nine genotypes were evaluated for resistance to WFT feeding damage. Individual insect-free plants of each genotype were inoculated with approximate to30 laboratory-reared WFT. Thrips were allowed to feed on individual plants for a 4-week period during which visual evaluations were conducted every 2 weeks to estimate feeding damage. Feeding damage varied among genotypes and increased with time. At 4 weeks after inoculation, 'Cajun Carmine' and 'Super Elfin Lavender' had significantly less feeding damage than all other genotypes. The San Vito Wildi-type germplasm was determined to be highly susceptible to thrips feeding damage based on visual evaluations. Because WFT feeding damage varied among genotypes, the potential for improving impatiens resistance to WFT exists within commercially available germplasm.