Optimization of Orius majusculus release: photoperiodic sensitivity at diferent temperatures and storage of diapausing adults

Abstract

The photoperiodic sensitivity and storage of Orius majusculus (Reuter) from Antalya was investigated to obtain data forthe optimization of its release. In the current study, it was not possible to induce a high (up to 100%) incidence of diapause unless allthe nymphal instars and adults were successively exposed (i.e. full exposure) to a short day length (11.5 h) at constant temperaturesof 18 and 26 °C, and fuctuating temperatures of 10/26 °C. Hence an intermittent exposure to long day lengths, even for short periodsof time (only during instars IV V or adult stage), would avoid a high incidence of diapause at 10/26 °C and 26 °C. Te response of O.majusculus nymphal instars and adults to a short day length with a low incidence of diapause under fuctuating temperatures suggeststhat greenhouses, where such temperatures prevail, provide an environment that is conducive to diapause prevention. Te release ofadults is a better approach than the release of nymphs, since the adults and their nymphs, until the eclosion of new adults, are expectedto respond to short day lengths with a low incidence of diapause in greenhouses. When nymphs are released, on the other hand, a highincidence of diapause would be inevitable. Increasing the constant temperature to 30 °C at full exposure did not prevent diapause andconsequently did not change the incidence of diapause. Storage of diapausing O. majusculus adults was possible for 1 month with ahigher survival rate and fecundity than in a study based on the storage of nondiapausing adults at a lower temperature.