Potential of two omnivorous iolinid mites as predators of the tomato russet mite, Aculops lycopersici

Abstract

Two iolinid predatory mites were studied in the laboratory as potential biological control agents of the tomato russet mite, Aculops lycopersici (Acari: Eriophyidae). The development, reproduction and predation capacity of Pronematus ubiquitus and Homeopronematus anconai (Acari: Iolinidae) on A. lycopersici were investigated. Developmental time from egg to adult at 25°C averaged 9.59, 9.31 and 9.52 days for P. ubiquitus on A. lycopersici, A. lycopersici and Typha angustifolia pollen, and pollen only, respectively. H. anconai required 11.18, 10.39 and 11.90 days to complete development on the respective diets. Survival of the immature stages exceeded 83% on all diets for both iolinids. In experimental arenas, both predators caused a substantial reduction of the immature population development of A. lycopersici. The number of tomato russet mite offspring was reduced by 78% and 57% by P. ubiquitus and H. anconai, respectively. The addition of pollen to the arena lowered this population reduction to 35% and 27% for the respective predators. However, supplementing a diet of tomato russet mites with pollen signi cantly increased the fecundity of both predatory mites from 14-15 to 24-25 eggs over a ve-day period. The results suggest that both P. ubiquitus and H. anconai have good potential to suppress A. lycopersici populations and that T. angustifolia pollen can support population establishment of the predators. Key MessageP. ubiquitus and H. anconai are potential biological control agents of A. lycopersici T. angustifolia pollen can support population establishment of both predators Although pollen supplementation lowered predation rates, it substantially increased the fecundity of both iolinids Overall, P. ubiquitus developed faster and suppressed A. lycopersici stronger as compared to H. anconai Survival and fecundity was similar for both iolinids on all diets tested Further eld studies are required

Modelling the interaction between a pest (Aculops lycopersici), two predators (Pronematus ubiquitus and Macrolophus pygmaeus) and climate variables: a 3‐year greenhouse study in a tomato crop

“…In the case of P. ubiquitus, this could be pollen (T. angustifolia, which was provided weekly), fungi or plant sap. [18][19][20] The population density of P. ubiquitus appeared to be independent of the pest A. lycopersici. A laboratory trial showed that survival and fecundity were similar when P. ubiquitus was fed with pollen plus A. lycopersici or pollen only.…”

“…When the density of a particular prey species is low, the generalist predator will feed on something else. In the case of P. ubiquitus , this could be pollen ( T. angustifolia , which was provided weekly), fungi or plant sap 18–20 . The population density of P. ubiquitus appeared to be independent of the pest A. lycopersici .…”

“…Thus, according to the model, it is impossible for A. lycopersici to reach very high densities in the presence of P. ubiquitus under normal greenhouse circumstances, hereby confirming P. ubiquitus' status as an efficient biocontrol agent of A. lycopersici. 18,19 Another hypothesis to explain the density-dependent effects for A. lycopersici is the effect on the tomato trichomes. As a result of plant feeding, A. lycopersici induces plant responses that can result in deterioration of tomato trichomes.…”

“…The main problem with these mites is that they cannot survive, move or reproduce on tomato due to the plant's glandular trichomes 10 . Although early studies describe the mite Pronematus ubiquitus (McGregor) (Acari: Tydeidae) as a predator of A. lycopersici , 17 the species has only recently been identified and valued as a biocontrol agent in tomato crops 18,19 …”

“…10 Although early studies describe the mite Pronematus ubiquitus (McGregor) (Acari: Tydeidae) as a predator of A. lycopersici, 17 the species has only recently been identified and valued as a biocontrol agent in tomato crops. 18,19 Pronematus ubiquitus is a small (<300 μm) omnivorous predatory mite (Acari: Iolinidae). Iolinid mites feed on pollen and plant sap, 18,20,21 small prey-like eriophyid 22 and tetranychid mites, 22,23 and fungi.…”