Functional response of Amblyseius swirskii (Acari: Phytoseiidae) on untreated and Beauveria bassiana-treated Frankliniella occidentalis (Thysanoptera: Thripidae)

Thrips are important greenhouse pest that cause transmitting viruses in addition to direct damage. Functional response is an important factor in selection of natural enemies for the biological control of pests. The general predator Amblyseius swirskii and entomopathogenic fungus are the most important natural enemies of western flower thrips (WFT) Frankliniella occidentalis in most area. The functional response of the predatory mite, A. swirskii was examined on either untreated or Beauveria bassiana (isolate JEF-007) treated larvae of the WFT after three time intervals: 0, 24 and 36-h treatments. The functional response were studied in the laboratory condition (25±1 ºC, 70±10 % RH and photoperiod of 16:8 h (L: D)), and densities of 2, 4, 6, 8, 10, 12, 16 and 20 larvae per Petri dish, over 24h. The data were good fit to Rogers-II functional response model for all of untreated and B. bassiana-treated insects. Comparisons of the results of functional response parameters in different treatments indicated that the handling time on western flower trips 24 hours after infection had significantly different with the control but there were no significantly different among treatments control, 0 hour after infection and 36 hour after infection of the fungus.