Light quality influences trap catches of Frankliniella occidentalis (Pergande)and Trialeurodes vaporariorum (Westwood)

Abstract: The effect of different light environments on trap catches of Frankliniella occidentalisand Trialeurodes vaporariorum was investigated in a commercial greenhouse rose productionunit during late autumn. Two top light treatments were used: 1) High pressure sodium lamps(HPSLs) and 2) HPSLs and light emitting diodes (LEDs) with 20% blue and 80% red light. Morethrips and fewer whiteflies were caught on yellow sticky traps, and more thrips were found in theflowers, in areas were LEDs were used in addition to HPSLs compared to areas where onlyHPSLs were used. No effect of the light treatments was found on the population level ofAmblyseius swirskii, but a lower ratio of predatory mites to thrips was found on the plants whereLEDs were used. The results suggest that using blue and red LEDs as interlighting, or otherwisesupplementary to HPSLs, will change thrips and whitefly spatial distribution in the rose crop, andthat natural enemy release rates probably need to be adjusted accordingly.