Biological Characteristics of Agistemus terminalis (Quayle) (Acarina : Stigmaeidae) as a Predator of the Citrus Red Mite, Panonychus citri (McGregor)

Abstract

Adult females of A. terminalis fed preferably on eggs of P. citri, and seldom on the larvae and protonymphs. When the density of prey eggs was lower (2-16 eggs/leaf), rates of predation per day by predator were 30-45%. The average number of eggs consumed per day by adult females of the predator was 1 at 15 °C, 2.4 at 20 °C, 6.1 at 25 °C and 3.4 at 30°C. The average number of eggs laid per day by the predator was 1.5 at 20°C, 3.8 at 25°C and 3.1 at 30°C. At 25°C and 30°C, finite rates of natural increase of A. terminalis per 10 days (e10rm) were lower than those in P. citri, but were almost equal to those in P. citri at 20°C. At 25°C, A. terminalis suppressed its prey population under 3.4 adult females per leaf, when the ratio of predators released was higher than 5 : 1 (prey : predator). This predator population was dependent on the prey density. The degree of suppression of the prey population by A. terminalis was considerably lower than that in Amblyseius eharai Amitai et Swirski. A. terminalis hibernated in adult females on the underside of leaves in the citrus grove, but their mortality rate was very high. © 1983, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.