Dispersal of Amblyseius swirskii (Acari: Phytoseiidae) on High-Tunnel Bell Peppers in Presence or Absence of Polyphagotarsonemus latus (Acari: Tarsonemidae)

Amblyseius orientalis shows high consumption and reproduction on Polyphagotarsonemus latus in China

The broad mite, Polyphagotarsonemus latus (Banks) (Acari: Tarsonemidae), is a cosmopolitan pest that infests many greenhouse crops. Biological control is an important way to control P. latus, with predatory mites being the most widely used natural enemies of this pest. The purpose of this study is to evaluate the capabilities of three native phytoseiids in China (Neoseiulus californicus, Neoseiulus barkeri and Amblyseius orientalis) in controlling P. latus, using Amblyseius swirskii as a control, a commercial biocontrol agent of this pest widely used in Europe. Consumption, development, and reproduction of the four species when fed with P. latus were assessed, and their life table parameters were estimated and compared. Among the three native species, A. orientalis has the highest consumption rate of P. latus (29.0 per day), the shortest developmental duration (5.3 days), and the highest cumulative fecundity (13.5 eggs/female). Overall, its intrinsic rate of increase (rm) is 0.12, comparable to that of A. swirskii. Among the three candidates, A. orientalis is the only one whose population increase might be expected when fed with P. latus. Therefore, we propose A. orientalis to be a potential biocontrol agent for this pest in China.

Acaricide-Mediated Colonization of Mite-Infested Coconuts by the Predatory Phytoseiid Neoseiulus baraki (Acari: Phytoseiidae)

Walking is important to dispersal on plants and colonization of new plants by predatory mites, and this activity is potentially affected by the presence of acaricides. This possibility was investigated in coconut fruits infested with the coconut mite, Aceria guerreronis Keifer (Acari: Eriophyidae), where colonization by the predator Neoseiulus baraki (Athias-Henriot) (Acari: Phytoseiidae) was monitored. The following acaricides were evaluated for influence on the process of colonization by the predatory mite: abamectin, azadirachtin, and fenpyroximate. Water-treated fruits were used for comparison. Experiments were conducted with and without freedom of choice on coconut fruits with the release and recapture of females of N. baraki marked with fluorescent ink. A confinement experiment was also carried out on coconut bunch rachis sprayed or not sprayed with the acaricides. The predatory mite N. baraki avoided contact with acaricide-contaminated areas. After the predators were released on the fruits or bunch rachis, larger numbers were recaptured under the bracts than on the surface of the fruits. The number of predators recaptured in all experiments was lower in the treatments with acaricides than in the control. Among the acaricides tested, azadirachtin least affected N. baraki colonization. Therefore, the presence of the tested acaricides indeed interferes with N. baraki dispersal within plants and the coconut fruit colonization.