How many Orius laevigatus are needed for effective western flower thrips, Frankliniella occidentalis, management in sweet pepper?

Frankliniella occidentalis (Pergande) is a primary pest of greenhouse crops worldwide, in organic and integrated pest management control practices, Onus spp. are frequently released for thrips control. However, Onus spp. are relatively expensive to produce. More cost-efficient rearing systems and reduced release rate might reduce the expense. In these trials, we released Onus laevigatus (Fieber) at different rates with or without simultaneous release the predatory mite Amblyseius swirskii Athias-Henriot, another known thrips predator, which is less expensive to rear. There was no significant difference in the number of O. laevigatus recovered in which either 2 or 6 individuals were released per square meter, and there was no difference in thrips control among any of the release strategies using O. laevigatus, suggesting that a reduced release rate can maintain effective thrips control. There was no significant difference in the quality or quantity of the pepper yield between treatments in which either 2 or 6 Orius/m(2) or Onus plus A. swirskii were released. (C) 2011 Elsevier Ltd. All rights reserved.