Early Detection and Mass Trapping of Frankliniella occidentalis1,and Thrips tabaci1in Vegetable Crops

Eric T. Natwick, John A. Byers, Chang-chi Chu, Martin Lopez, Thomas J. Henneberry
2007 The Southwestern entomologist  
Western flower thnps, Frankliniella occidental/s (Pergande), and onion thrips, Thrips labaci Lindeman, are economic pest insects of head lettuce, Lactuca safiva L., and dehydrator onions, A/hum cepa L., in the Imperial Valley, California. Colored sticky traps were evaluated as potential detection and monitoring devices of the two thrip species over a two-month period in 2006. Results showed that blue sticky card traps consistently captured more adult thrips of both species compared to yellow
more » ... mpared to yellow sticky card traps. Numbers of thrips captured on blue sticky traps were positively correlated to numbers captured on yellow sticky traps. Adult thrips were captured in much higher numbers on sticky card traps than recovered from whole plant samples. Significant negative correlations between F. occiden ta/is numbers on plant samples and colored sticky traps suggest that adults left lettuce plants and were attracted to nearby traps. In addition, the numbers of thnps caught on traps relative to estimated plant populations support the hypothesis that mass trapping was significant In the treated area. Spectroradiometric and RGB (red, green, blue) digital image color analysis of the traps in sunlight showed the blue sticky cards reflected considerably more light in the 400-500 nm range (R = 49, G = 187, B = 255) than the yellow sticky cards that reflected more light in the 550-700 nm range (R = 227, G = 234, B = 67). Because blue sticky card traps captured many times more adult thrips than recovered from whole plant samples, blue traps may be more sensitive in detecting early presence of thnps in lettuce and onion fields. 110
doi:10.3958/0147-1724-32.4.229 fatcat:lwfw33nmrjbx3myekd23ombn3m