Responses of Selected Thysanoptera1 to Colored Surfaces3

The color preferences of 3 thrips populations were determined by placing 7.5×12.7-cm painted cards coated with Stickem® on 1.3 m stakes in a rye field. Sericothrips variabilis Beach was most attracted to yellow, Anaphothrips obscurus Muller and Frankliniella fusca (Hinds) to yellow and white, and F. tritici (Fitch) to yellow and low ultraviolet remitting white surfaces. In the greenhouse, the thrips Taeniothrips simplex (Morison) was most attracted to orange. Only F. tritici , a general flower inhabitant, clearly distinguished between low and high UV remitting white surfaces. Dilutions of paints with zinc white (a low UV remitter) revealed a consistent linear relationship between the catch of F. tritici and the percentage zinc white in the mixtures within the upper and lower limits of response. In a black-zinc white dilution series, the catch of F. tritici increased at a near linear rate with the logarithm of the increase in the mean percent remission from 400 to 660 nm. Dilutions of red or black with lead white (a high UV remitter) produced no distinctive responses; however, certain dilutions of yellow with lead white caught more F. tritici than the corresponding zinc white dilutions. Responses to color glass filters placed over various white or metallic surfaces indicated a high preference of F. tritici for surfaces which remit only the near UV, the visible spectrum above 500 nm or which have a strong peak remission in the blue-violet region. It was also confirmed that elimination of the near UV remission by lead white and by aluminum foil increased their attractiveness to the level of zinc white. Lead white borders (28 cm2) greatly reduced the catch of all thrips species on 7 cm2 yellow center cards, and a white paper border greatly reduced the catch of F. tritici on all 5 colors tested.