Brilliant Blue Chromatic Traps Plus Commercial Attractors are Effective Capturing Adults Frankliniella Occidentalis (Thysanoptera: Thripidae) in Blackberry Crops

Abstract

Western flower thrips (WFT) are a major insect pest of blackberry (Rubus ulmifolius, Rosaceae) crops in Mexico, causing significant damage to blackberry crops. Yellow and blue traps are used to monitor adult thrips populations during the blossom season. However, the effect of different shades of these colours on the capture of Frankliniella occidentalis Pergande (Thysanoptera: Thripidae) is not clearly known. The current study evaluated four shades of yellow (opaque, neutral, brilliant, and phosphorescent) and three shades of blue (opaque, neutral, and brilliant), subsequently, the most attractive shade (brilliant blue or high lustre blue was selected, and different geometric figures (circle, half-circle, rhombus, triangle, inverted triangle, and square) were evaluated on a black background in blackberry crops. Brilliant blue and phosphorescent yellow traps captured the highest number of WFT adults; but brilliant blue traps captured numerically more WFT adults than phosphorescent yellow traps. The use of different geometric figures of brilliant blue on a green background did not improve thrip capture compared to the brilliant blue trap without a background. The kairomone Lurem-TR increased the number WTF adults captured 2 - 3 times more the unbaited trap, and 2 mg of eugenol increased 1.5 - 2.5. These results are useful to complement the monitoring system for F. occidentalis in host crops of this pest.