Influence of trap shape, size and background colour on captures of Frankliniella occidentalis
Different types of sticky traps to catch Frankliniella occidentalis (EPPO A2 quarantine pest) have been studied and compared in a cucumber greenhouse, in Canada. Four, three-dimensional trap shapes were tested: a sphere, a cube, an cylinder and a rectangular prism. The influence of size, colour (violet or yellow) of the traps was studied. Traps were suspended inside plywood frames, painted on the inside (violet, yellow, blue or green) and the influence of this background colour was also evaluated. Among traps with cubic, spherical, rectangular prism, or cylindrical shapes of approximately the same surface areas, only yellow cylindrical traps in front of a violet background were significantly more attractive than the other shapes. Yellow or violet traps placed in front of their identical background colours trapped fewer thrips than if placed in front of certain backgrounds that provide better contrast. When comparing three dimensional traps with two-dimensional traps, blue cylindrical traps did not catch significantly more thrips per square centimetre of trap area than the flat trap of similar diameter and height. The authors concluded that their data indicate that the use of three-dimensional traps will not improve trapping efficacy. Flat traps are less expensive and easier to handle. But their efficacy could be improved by placing yellow traps in front of blue or violet background, or if violet of blue traps were placed over a yellow background. However, the authors recognize that the placing of permanent coloured background structures would not be economically justified for existing monitoring programmes that do not intend to use mass trapping as a management strategy against F. occidentalis.
Sources
Vernon, R.S.; Gillespie, D.R. (1995) Influence of trap shape, size, and background colour on captures of Frankliniella occidentalis (Thysanoptera: Thripidae) in a cucumber greenhouse.
Journal of Economic Entomology, 88(2), 288-293.