Preference of Sweetpotato Whitefly Adults to Cucumber Seedlings Grown under Two Different Light Sources

Abstract

We evaluated the preference of adult sweetpotato whitefly [SPWF (Bemisia tabaci biotype B)] to cucumber (Cucumis sativus) seedlings grown under fluorescent lamps (FLs) or metal-halide lamps (MLs) that provided a spectrum similar to that of natural light. Cucumber seedlings were grown under FLs or MLs at a photosynthetic photon flux of 350 μmol·m−2·s−1 in a 12/12-hour light/dark cycle. The red:far red (R:FR) ratio of FL was 7.0 and that of ML was 1.2. Pairs of cucumber seedlings, one grown under FLs and the other under MLs, were then placed in cages and about 100 SPWF adults were released. There were significantly fewer SPWF adults on the FL cucumber seedlings (36%) than on the ML seedlings (64%) 24 hours after release. FL cucumber seedlings had higher chlorophyll content and thicker leaves than ML seedlings. The lower attractiveness of the FL cucumber seedlings was probably due to changes in morphologic characteristics such as the leaf color and thickness resulting from high R:FR illumination of FL. The fact that light quality affects the plant attractiveness to herbivores should be considered in selecting light sources for transplant production under artificial light.