LAUSR

Abstract The functional response of Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) preying on Tetranychus urticae Koch (Acari: Tetranychidae) eggs on leaf discs of three varieties of rosebush was determined at eight time intervals (0–2, 2–4, 4–6, 6–8, 8–10, 10–12, 12–24, and 0–24 h). Some differences in handling time (Th) and attack rate (a′) among the three plant varieties (Royalty, Pareo, and Starlite) were observed, but the functional response on the three varieties shifted from Type II to Type III at three time intervals within the 24-h observation. The observed shift in functional response was likely due to different rates of attack and handling times linked to the prey and the plant variety.