Solid artificial diets for the phytoseiid predator Amblyseius swirskii

Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) is a key predator of a wide range of pests including thrips, whitefly and several mite pests. A number of artificial diets have been developed for this predator, but all of these are liquid, complicating their use in mass production. In the present study, we investigated the survival, development and reproduction of A. swirskii fed on several dry artificial diets: the tested diets were freeze dried forms of previously developed liquid meridic artificial diets supplemented with extracts of decapsulated cysts of Artemia franciscana Kellogg (Anostraca: Artemiidae) or with pupal hemolymph of Chinese oak silkworm Antheraea pernyi (Guérin-Méneville) (Lepidoptera: Saturniidae), and newly composed powdered meridic artificial diets supplemented with ground dry A. franciscana cysts or lyophilized pupal hemolymph of A. pernyi. Performance of the mite on the artificial diets was compared with that on cattail pollen (Typha latifolia L.). Developmental time of A. swirskii females offered lyophilized diets was significantly shorter than on powdered diets. Total fecundity was significantly higher for females fed on the lyophilized diets than for those maintained on the powdered diet with A. franciscana. Daily oviposition rates were similar on T. latifolia pollen and both lyophilized diets but lower on both powdered diets. The highest intrinsic rate of increase was observed when A. swirskii was fed on T. latifolia pollen (0.210 females per female per day), followed by the freeze dried diets enriched with A. pernyi and A. franciscana (0.195 and 0.184 females per female per day, respectively), and the lowest growth rates were observed on the powdered diets supplemented with A. franciscana and A. pernyi (0.159 and 0.158 females per female per day, respectively). In conclusion, the phytoseiid was able to effectively feed on solid, powdered artificial diets. Freeze-drying of liquid diets did not influence their value to support the development and reproduction of A. swirskii. For mass rearing purposes, these dry diets have several advantages over liquid ones, including more convenient application and storage. Furthermore, they are believed to have better potential for use as supplemental foods to sustain predatory mite populations in the crop after release.