Mass-rearing of Pyemotes zhonghuajia (Prostigmata: Pyemotidae) with substitute hosts

Chinese beetle mite (Pyemotes zhonghuajia) is a new species, which was first discovered in China and has broad application prospects. In this experiment, preference of P. zhonghuajia for and development on substitute and natural hosts were investigated, as well as the development of the mites reared by different hosts. Results showed that the most favorite hosts for P. zhonghuajia were larvae of Sitotroga cerealella, the substitute host, and Stenhomalus tainoons, the natural host, with selection coefficient of 0.6743 and 0.6493, respectively. The second favorite hosts were Scolvtua seulensis and Sitophilus zeamai, with selection coefficient of 0.5006 and 0.4619, respectively. The selection coefficient of the first group was significantly higher than that of the second group, though no difference was observed within each group. When the mites were reared by substitute hosts of S. cerealella, S. zeamais and natural hosts of S. seulensis, S. taiwanu s, duration from inoculation to offspring production was 6.8, 7.9, 7.4, 7.8 d, respectively ; maximum expanding abdomen diameter of the female mite was 0.9871, 0.9243, 0.9662, 0.9423 mm, respectively; number of the female offspring per mother was 109.6, 105.5, 130.3, 115.9, respectively ; crawling speed was 5.51, 5.20, 5.89, 5.34 cm [center dot]min-1, respectively; and number of the hosts killed by per mite was 9.3, 9.3, 9.2, 9.6, respectively. Generation duration of the mite was significantly shorter when reared on S. cerealella than on other hosts, but no difference was observed in other characteristic of the mite reared with either natural hosts or substitute hosts. Thus, it is recommended that larvae of S. cerealella and S. zeamais could be used as substitute hosts for mass rearing P. zhonghuajia