Mechanical application of orius laevigatus nymphs for the control of Frankliniella occidentalis in greenhouse crops

The development of improved technology for use of beneficial organisms in greenhouse crops includes mechanical application methods to that can reduce labour costs compared to manual application while preserving the quality of the applied natural ene-mies. A pneumatic distribution system, verified as effective in previous study with mites (Phytoseiulus persimilis Athias-Henriot and Amblyseius swirskii Athias-Henriot), was tested for application of the predatory bug Orius laevigatus (Fieber). Laboratory and field tests were used to assess the efficiency of mechanical distribution of nymphs of O. laevigatus. The efficiency of mechanical distribution was evaluated comparing the biological parameters of the predator (survival, fecundity, fecundity rate and lon-gevity) dispensed mechanically with to those following manual distribution. Nymphal survival immediately after and 10 days after the dispensing was calculated as proportion of nymphs reaching adulthood. We found that mechanical applications caused a reduction of predator survival in comparison to manual sprinkling of 21% and 36% immediately after and 10 days after the dis-pensing, respectively. The causes of the reduced survival from mechanical application were attributed to the combined effect of the extraction system and the velocity of airflow that transports the predator. Moreover, the biological parameters of adult females that survived mechanical distribution as nymphs, showed no significant differences compared to the same following manual dis-tribution. In the greenhouse test, the mechanically released nymphs of O. laevigatus were as effective as those manually released in controlling Frankliniella occidentalis (Pergande) in a cucumber crop. Consistently, the yield and quality of cucumber fruits did not show differences in the mechanical vs. manual application. Mechanical application time was significantly lower compared to manual application, determining a 5.5 higher effective work capacity compared to traditional manual distribution.