Laboratory evaluation of commercially available and naturally occurring predatory mites against Thrips parvispinus...

Predatory mites are widely used to control major thrips pests in agricultural systems. The invasive Thrips parvispinus represents a challenge to economically important plants, with limited information available on the potential of predatory mites to control it. Eight commercially available predatory mites in the USA: Amblyseius swirskii, Amblyseius andersoni, Amblydromalus limonicus, Neoseiulus cucumeris, Neoseiulus californicus, Euseius degenerans, Anystis baccarum, and Stratiolaelaps scimitus; and four naturally occurring predatory mites in Florida: Proprioseiopsis ovatus, Neoseiulus longispinosus, Amblyseius largoensis, and Amblyseius adhatodae were evaluated. In choice experiments, predators were exposed to pairs of T. parvispinus stages (first instar-L1, second instar-L2, prepupa, pupa, and adult) to assess preference. Subsequent no-choice assays quantified predation and oviposition on the preferred stage: all phytoseiids were offered L1, P. ovatus prepupae, A. baccarum L2, and S. scimitus L2 or prepupae. Prey consumption and oviposition were recorded every 24 h for four days. Neoseiulus longispinosus, A. largoensis, and A. adhatodae did not feed on T. parvispinus. The remaining phytoseiids preferred L1 over L2. Anystis baccarum preferred L2 and adult stages. Stratiolaelaps scimitus showed no stage preference, varying according to the offered stages. When offered L1, the highest predation was recorded for E. degenerans (5.78 L1/day), A. swirskii (4.14 L1/day), and N. cucumeris (3.23 L1/day). When offered L2, A. baccarum consumed 12.88 L2/day and S. scimitus 6.29 L2/day. All predators oviposited when feeding on T. parvispinus. Anystis baccarum produced one mass of 24 eggs, while the highest oviposition was observed for A. swirskii with 1.37 eggs/day. Our results suggest A. baccarum, S. scimitus, E. degenerans, N. cucumeris, and A. swirskii as the most promising predators of T. parvispinus.