ABSTRACT

Laboratory results from a previous study that investigated the prevention of reproductive diapause induction in the insidious flower bug, Orius insidiosus Say (Hemiptera: Anthocoridae), by extending photoperiod with supplemental blue light were evaluated using a computer simulation model of O. insidiosus population dynamics. The state variable approach of model formulation was used. Validation of the simulation model was conducted during a nine-week chrysanthemum, Dendranthema grandiflora (Ramat.) Kitamura, production cycle. The validation study was used to evaluate the usefulness of the simulation model in predicting O. insidiosus population dynamics in conditions of unlimited western flower thrips, Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), prey and varying temperature and photoperiod, and whether supplemental blue light would enhance the biological control of F. occidentalis. Treatment regimes were either a short photoperiod of 9-h ambient light or a long photoperiod consisting of 9-h ambient light followed by 6-h of blue light (400-500 nm) at a blue light intensity of ≈0.97 W●m². The simulation model predicted the dynamics pattern observed in O.insidiosus densities in both light regimes and predicted the dynamics pattern of O.insidiosus adults well until approximately week 5, although the timing of peak adult occurrences in both light regimes was similar. In the blue light regime, O. insidiosus adult populations were sufficient for reproduction to reach levels that significantly reduced thrips populations. There was a higher potential of female O. insidiosus reproduction in the blue light regime compared with the short photoperiod regime. Additionally, chrysanthemum flowered reliably in extended blue light. These results in a fluctuating greenhouse environment confirm our laboratory findings that extending photoperiod with blue light prevents reproductive diapause induction of O. insidiosus.

¹Maine Agricultural and Forest Experiment Station Journal Article number 2118