Bioassays were conducted under artificial light with a (12L:12D) photoperiod and an average light intensity of 55 mmol/sec/m2 to evaluate the toxicity of the photoactivate dye, phloxin B, to mid second-instar citrus thrips, Scirtothrips citri (Moulton). One hundred percent mortality occurred when thrips fed upon cane molasses diluted to ca. 3% soluble sugar (standard feeding stimulant) containing 1% by weight phloxin B. The LC50 and LC90 occurred at 0.009 and 0.049% dye, respectively, when thrips fed upon the standard plus dye. Eight feeding stimulant candidates (FSC) were evaluated for feeding preference against the standard. Dye at a concentration of 0.01% was added to each FSC in a series of 5 bioassay trials. Citrus thrips did not prefer the two FSC derived from sugar beet, CMS (condensed molasses solubles), and CSB (concentrated separated by-products) above that of the standard. Mo-Bait (a commercially available imitation molasses food flavoring) and 2 FSC derived from partially dehydrated citrus peel, concentrated citrus peel liquor CCPL1 and CCPL3, were preferred above that of the standard. Thrips fed equally upon the standard and CCPL2. Bioassays were also conducted to evaluate six commercially available surfactants. Surfactant was added at a rate of 0.25% to the standard plus 0.01% dye to evaluate the impact upon thrips mortality. Silwet, Kinetic, Cohort, Dyne-Amic, and Hyper-Active significantly reduced mortality below that of the standard plus dye without a surfactant. Tween 60 had no significant impact upon thrips mortality.
Species 1: Thysanoptera Thripidae Scirtothrips citri (citrus thrips)
Keywords: citrus thrips, phloxin B
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA