Suitability of different plant pollens as supplementary food source and natural prey for predatory mite, Neoseiulus barkeri Hughes (Acari: Phytoseiidae)

The predatory mite, Neoseiulus barkeri, is one of the most important biocontrol agents of the two-spotted spider mite Tetranychus urticae Koch or other pests. Some of the phytoseiid mites utilize pollen as a food source and develop and reproduce on a pollen diet as well. They require pollen for successful development and reproduction. The predatory mite was collected from cucumber field infested with two-spotted spider mite in Khoramabad in Lorestan province. In this research, the effect of diets such as, maize pollen, walnut pollen, sunflower pollen, date pollen, bee pollen with or without two-spotted spider mite eggs in laboratory conditions (27±1˚C, 16L: 8D photoperiod and 70-80% RH) was compared. The life tables of the predator were constructed based on two- sex life table. The population parameters were estimated based on Chi & Liu’s model, using data of both sexes and the variable developmental rate among individuals. The results showed that total immature mortality when N. barkeri fed on only sunflower pollen or bee pollen was 100%.The developmental times of different stages on tested plant pollen showed significant differences. The progeny sex ratio when fed on date pollen (58%) and spider mite eggs (77%) and tested plant pollen plus spider mite was more female biased. The highest intrinsic rate of natural increase (r) was recorded when N. barkeri fed on corn pollen + spider mite (0.244 day-1) and on date pollen + spider mite (0.225 day-1). The female longevity when fed on date pollen +spider mite egg (12.12 days) and walnut pollen + spider mite egg (11.15 days) were longer than the other treatments. The comparison between predatory mite that fed on pollen only and mites that fed on pollen+spider mite showed that longevity of mites when fed on pollen only was longer, however, the fecundity rate of predatory mite when fed on pollens and spider mite was higher. The predatory mite fed on maize, walnut and date pollens, was able to complete the developmental stages and oviposit. Maize, walnut and date pollens were suitable alternative foods for the mass rearing of this predator.