The succession of phytophagous and phytoseiid species in a newly planted apple orchard without insecticide applications

Abstract

Population dynamics of phytophagous and phytoseiid mites in a newly planted apple orchard were investigated for the consecutive 5 years just after the stop of insecticide applications, to verify the effect of the phytoseiids on the dominance and density of phytophagous mite species. Phytoseiid mites were typically most abundant in autumn from 2005 to 2008, except in 2009 when there were two marked peaks. Although 10 phytoseiid mite species were collected over the five-year study period, species abundance and composition changed gradually over time. The phytophagous mites were most abundant in the autumn of 2005, but the timing of peak occurrence and density changed as the study progressed. Changes in the abundance and species composition of the phytoseiid mite communities, Tetranychus urticae abundance was not suppressed by the phytoseiid mites. Although Panonychus ulmi was suppressed to insecticide application, P. ulmi may affect T. urticae abundance under a no-insecticide regime. Finally, T. urticae disappeared and P. ulmi and Aculus schlechtendali decreased in abundance. Although not marked, Typhlodromus vulgaris played a key role in affecting the stability of mite communities in apple orchards when no insecticides were applied.

Management of apple orchards to conserve generalist phytoseiid mites suppresses two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae)

“…Many phytoseiid mite species-not only N. womersleyi, but also many generalist phytoseiid mites, especially Typhlodromus vulgaris Ehara and Amblyseius tsugawai Ehara-have been observed in apple orchards managed without insecticide spraying (Kishimoto 2002;Toyoshima 2003;Toyoshima et al 2011). These observations suggest that if the generalist phytoseiid mites could be conserved in apple orchards, the occurrence of T. urticae might be suppressed.…”