A Preliminary Assessment of Amblyseius andersoni (Chant) as a Potential Biocontrol Agent against Phytophagous Mites Occurring on Coniferous Plants

SIMPLE SUMMARY: Amblyseius andersoni (Chant) is a predatory mite frequently used as a biocontrol agent against phytophagous mites in greenhouses, orchards and vineyards. In Europe, it is an indigenous species, commonly found on various plants, including conifers. The present study examined whether A. andersoni can develop and reproduce while feeding on two key pests of ornamental coniferous plants, i.e., Oligonychus ununguis (Jacobi) and Pentamerismus taxi (Haller). Pinus sylvestris L. pollen was also tested as an alternative food source for the predator. Both prey species and pine pollen were suitable food sources for A. andersoni. Although higher values of population parameters were observed when the predator fed on mites compared to the pollen alternative, we conclude that pine pollen may provide adequate sustenance for A. andersoni populations when prey are absent. Based on our results and due to the fact that the predator was previously recorded as sympatric with O. ununguis and P. taxi, we consider it to be a promising biocontrol agent of these pests. ABSTRACT: Development, survival and reproduction of Ambyseius andersoni (Chant), a predatory mite widely distributed in Europe, were assessed on different food items. These included two key pests of ornamental coniferous plants, i.e., Oligonychus ununguis (Jacobi) and Pentamerismus taxi (Haller) and pollen of Pinus sylvestris L. The rationale behind these experiments was to provide a preliminary assessment of the potential of A. andersoni as a biocontrol agent of the above phytophagous arthropods and evaluate pine pollen as an alternative food source for the predator. Under laboratory conditions (23 ± 0.5 °C, 70 ± 10% RH and 16L:8D) A. andersoni was able to feed, develop and reproduce on all tested diets. The shortest development time (egg to female) was obtained when the predator fed on P. taxi (mean = 5.12 d) and the longest was on pine pollen (mean = 6.55 d). The r(m) value was significantly higher on both tested prey (0.166 on P. taxi and 0.160 on O. ununguis) than on pollen (0.139). Thus, we do not recommend pine pollen for mass rearing of A. andersoni; however, we conclude that pollen may provide sufficient sustenance for the predator population under field conditions when prey are absent. The potential of A. andersoni as a biocontrol agent of O. ununguis and P. taxi is discussed.