Evidence for suppressing coconut mite, Aceria guerreronis by inundative release of the predatory mite, Neoseiulus baraki

In this paper, we report the first evidence for the suppression of coconut mite Aceria guerreronis Keifer (Acari: Eriophyidae) populations by augmenting the natural population of the predatory mite, Neoseiulus baraki (Athias-Henriot) (Acari: Phytoseiidae) by an inundative release with laboratory-bred N. baraki. On each of five coconut mite infested palms in two plantations in the same agro-climatic zone of Sri Lanka, 10,000 laboratory-bred N. baraki was released once and the numbers of both N. baraki and coconut mite were assessed over a period of 6 months. Irrespective of the plantation, release of N. baraki resulted in a significant increase in its population on released palms during the post-release period of 6 months with a mean number of 8.99 ± 1.03 per fruit compared to 6.19 ± 0.80 per fruit on unreleased palms. A single release of N. baraki showed a highly significant positive impact on the coconut mite population in the released palms in both plantations. The mean numbers of coconut mites per fruit were 1264.77 ± 139.07 and 1815 ± 46 in the released and unreleased palms, respectively, during the sampling period.