27 research outputs found

    Development of an efficient trapping system for New Zealand flower thrips, Thrips obscuratus

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    Background: New Zealand flower thrips (NZFT), Thrips obscuratus (Crawford), is an economic pest of various horticultural crops in New Zealand and is recognised as a quarantine pest globally. Two chemical attractants (ethyl nicotinate and 6-pentyl-2H-pyran-2-one), three dispensers, three trap designs and four trap heights were investigated to determine the most effective method for monitoring NZFT. Phenology of NZFT at two locations was compared. Results: 6-Pentyl-2H-pyran-2-one in a polyethylene bag dispenser was the most attractive lure formulation and exhibited high stability in release rate trials. There was no difference in NZFT catch between vertical-panel and cross-panel traps, but both caught significantly more than delta traps. However, both types of panel trap had unacceptably high by-catch of native insects. Catch of thrips increased with height from 0 to 3m. Phenology of NZFT showed similar population trends at both locations, but with a timing difference of around 50 days. Conclusions: Delta traps containing 6-pentyl-2H-pyran-2-one in a polyethylene bag at 2m above the ground is the recommended method for monitoring NZFT, significantly improving the sensitivity, accuracy and labour input compared with prior methods. Long-term monitoring of NZFT could lead to more accurate economic damage thresholds and timing for when to apply insecticides

    Transition metal complexes as mediator-titrants in protein redox potentiometry

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    A selection of nine macrocyclic Fe-III/II and Co-III/II transition metal complexes has been chosen to serve as a universal set of mediator-titrants in redox potentiometry of protein samples. The potential range spanned by these mediators is approximately from +300 to -700 mV vs the normal hydrogen electrode, which covers the range of most protein redox potentials accessible in aqueous solution. The complexes employed exhibit stability in both their oxidized and their reduced forms as well as pH-independent redox potentials within the range 6 < pH < 9. The mediators were also chosen on the basis of their very weak visible absorption maxima in both oxidation states, which will enable (for the first time) optical redox potentiometric titrations of proteins with relatively low extinction coefficients. This has previously been impractical with organic mediators, such as indoles, viologens and quinones, whose optical spectra interfere strongly with those of the protein
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