The effect of temperature on the functional response ofPhytoseiulus persimilis(Acari: Phytoseiidae)

Abstract

Environmental variables, such as temperature, are important in determining the efficiency of biological control in ornamental crops. This paper examines the effect of temperature on the functional response of adult female Phytoseiulus persimilis to eggs of the spider mite, Tetranychus urticae. The functional response was determined using a new functional response assay technique with plant stems as an arena, rather than leaf discs. The use of plant stems allows the influence that plant structure has on predation to be incorporated into the assay. Control assays were also used (without predators) to estimate natural losses of prey. The data were analysed using a binomial model, with the use of Abbot's formula to correct for the losses in the controls. A combined equation to describe the effect of temperature and prey density on the predation rate of Phytoseiulus persimilis was derived. The results showed that more prey are eaten as the temperature increases from 15 degrees C to 25 degrees C, but the number of prey eaten then declines at 30 degrees C, although not to the levels seen at 20 degrees C. The implication of these results for biological control in ornamental crops, where the temperature can often exceed 30 degrees C, is discussed.

Gestión Integrada de la araña roja Tetranychus urticae Koch (Acari: Tetranychidae): optimización de su control biológico en clementinos

“…This result is in agreement with the higher interplant dispersal rate described for P. persimilis (Skirvin & Fenlon 2003;Walzer et al 2009;Alatawi et al 2011). …”

“…Phytoseiulus persimilis is a specialist predator of Tetranychus spp. and has shown high ability to quickly find and exploit new prey patches (Skirvin & Fenlon 2003;Walzer et al 2009;Alatawi et al 2011). During the foraging process, this species has a higher tendency to disperse from one plant to another rather than staying in the same plant.…”

Evaluation of phytoseiid predators for control of western flower thrips on greenhouse cucumber

“…Previous work has shown a decline in predatory ability at temperatures above 30°C (Skirvin and Fenlon, 2003) for the tropical species Phytoseiulus persimilis (Athias-Henriot), but already above 23°C for the North European species N. cucumeris (Shipp et al, 1996). Three of the mite species selected for this study were indigenous to The Netherlands, namely N. cucumeris (diapausing), Euseius finlandicus (Oudemans) and Typhlodromus pyri (Scheuten).…”

Verified and potential pathogens of predatory mites (Acari: Phytoseiidae)

“…The following set of symptoms was described for adult females from the NR-population: (1) size change by shrinkage to dorso-ventrally flattened form, (2) reduced fecundity caused by oviposition stop after shrinkage, (3) high mortality several days after shrinkage, (4) presence of excretory crystals in the legs, (5) low predation and/or feeding rate, (6) low excretion rate, (7) low degree of attraction to preyinduced plant volatiles, (8) short choice time during behavioural test, (9) early dispersal from prey-patches (Schütte et al 1995(Schütte et al , 2006a. Interestingly there are several publications in which remarkable peculiarities of P. persimilis have been stated, that are similar to the NR-syndrome among which (1) poor performance in terms of fecundity and survival (Steiner 1993a (6) unusual results concerning the predation rate (Skirvin and Fenlon 2003b). However, most of these studies did not consider or test the possibility of pathogen infection (for a detailed discussion see Schütte 2006).…”