Efficacy of stored indigenous predatory mite Phytoseiulus persimilis against Tetranychus urticae red form on eggplant under greenhouse conditions

Abstract

Cold storage is the most prevalent method to obtain sufficient number of natural enemies after mass rearing. In this study efficacy of stored indigenous Phytoseiulus persimilis Athias-Henriot against Tetrancyhus urticae red form on eggplant under greenhouse conditions were assessed after determining best storage conditions for the predatory mite stored at 5 and 10 oC with >98% RH conditions. Treatments in the greenhouse experiments consisted of T. urticae release (control), P. persimilis release stored at 5 oC for 15-day and unstored P. persimilis releases in 2014. In 2015, P. persimilis release stored at the same temperature for 30-day was made along with a control and unstored P. persimilis release. P. persimilis survival was 100% after 5.5 weeks at 5 oC, and was 75% at 10 oC for the same storage period. No significant difference was observed between the total mean numbers of T. urticae mixed stages in unstored and stored predatory mite release treatments for 15-day-stored predatory mites. On the contrary, a significant difference was detected among the T. urticae densities in all three treatments on some sampling dates at 30-day-stored predatory mite released treatments. The results showed that P. persimilis demonstrated great effectiveness on suppressing the T. urticae red form, and 15-day-stored indigenous strains of P. persimilis could be successfully used in the biological control of T. urticae in greenhouse-grown eggplant when compared to 30-day-stored P. persimilis.