Biocontrol of the shore fly Scatella tenuicosta with Hypoaspis miles and H-aculeifer in peat pots

摘要

Hypoaspis miles Berlese and H. aculeifer Canestrini (Acari: Laelapidae) were used against Scatella tenuicosta Collin (Diptera: Ephydridae) at the rates of 7, 14 and 36 mites per 0.3-l peat pot (1000, 2000 and 5000 per net-m(2) of peat) with mint (Mentha piperita L.) as the crop. The predators were applied either one day ( preventive control) or nine days after ( curative control) exposing the pots to the flies in the greenhouse. Based on the number of flies that emerged from the pots, the control efficacy of preventive H. aculeifer treatments at the rate of 36 mites per pot was 84 - 100 and 92 - 97 ( range over four replicate blocks) after two and three weeks, respectively, from the application. The control efficacy of curative treatments was 93 - 100 and 83 - 94 after two and three weeks, respectively, from the application. Preventive treatments with H. miles applied at the rate of 36 per pot controlled the flies by 92 - 100 and 68 - 97 two and three weeks, respectively, after the application. Curative treatments with 36 H. miles per pot were less effective ( - 53 - 68 and - 16 - 65, respectively). All treatments with lower mite rates with either species were ineffective. Due to more consistent reduction of fly numbers by Hypoaspis aculeifer, the species was concluded to be a better biocontrol agent of shore flies in short-term greenhouse crops grown in peat pots, probably due to its higher predation capacity in comparison to H. miles.