The effect of trap colour and aggregation pheromone on trap catchof Frankliniella occidentalis and associated predators in protected pepper in Spain

Abstract: In a greenhouse experiment, there was a strong effect of colour on sticky trap catch ofFrankliniella occidentalis in a sweet pepper crop. Blue traps attracted more thrips than yellowtraps (×2.4), clear traps (×9.3), or black traps (×34.7). The F. occidentalis aggregationpheromone, neryl (S)-2-methylbutanoate, increased trap catch in inverse proportion to theattractiveness of the trap colour (blue ×1.3, yellow ×1.7, clear x1.9, black x3.4). It is proposedthat in greenhouse crops, the most visually attractive trap colours are already catching a largeproportion of the thrips present in the area surrounding each trap, so the addition of scent cannotincrease trap catch by as much. The mirid predator Orius laevigatus was caught in low numberson traps and showed no attraction to specific trap colours, the predatory thrips Aeolothripstenuicornis was most frequent on yellow and blue traps and the staphylinid beetle Oxypodaexoleta was only found on black and clear traps. None of these predatory species were attractedto the F. occidentalis aggregation pheromone which can therefore be used to enhanceF. occidentalis trap catch without affecting natural enemy establishment.