Bioformulations are the preparations that contain beneficial microorganisms as active ingredients and they may represent a novel alternative to be used in crop protection because of their safety to humans and non-target organisms. Xenorhabdus sp. is an entomopathogenic bacterium that symbiotically associates with nematodes of the family Steinernematidae and has potential to be used in bioformulations due to its pesticide activities. The aim of this study was to determine the efficacy of bioformulations containing Xenorhabdus stockiae PB09 for controlling mushroom mites. The results showed that different Xenorhabdus bioformulations, including wettable powder (WP), liquid cell pellet (LC), and liquid supernatant (LS) were shown to cause very high miticidal activities at 90.25, 86.50, and 92.78 %, respectively. When X. stockiae PB09 bioformulations were stored at room temperature (28 ± 2 °C) and 4 °C for up to 60 days, their viable cells and efficacy were found to decrease. However, storing at 4 °C could relatively maintain both viable cells and efficacy of the bioformulations, especially after 45 days of storage, whereby all the formulations that were kept at 4 °C had 5–10 % and 2–15 times higher miticidal activities and viable cells than that kept at room temperature, respectively. Storing at 4 °C was more appropriate than room temperature for maintaining both viable cells and miticidal activities of all X. stockiae PB09 bioformulations. In conclusion, this study showed that WP and LC formulations were found to be effective and have potentials to be further developed as commercial products for controlling mushroom mites.

Luciaphorus perniciosus Rack is one of the most serious pests of several cultivated mushroom species including Ganoderma lucidum (Fr.), Flammulina velutipes Karst., Auricularia polytricha (Mont.) Saac., Lentinus polychrous Lev., and Lentinus squarrosulus (Mont.) Singer in Thailand. Adult female Lu. perniciosus produce offspring inside their physogastric hysterosomas, with all embryos developing through to the adult stage while remaining in the abdomen. Once the abdomen ruptures, the female parent dies and the offspring consisting of mostly fertilized female adults along with a few male adults continue to emerge from the cadaver of the mother for a period of several days. This peculiar type of reproduction after the death of the mother is a special case for life table analysis and has not been discussed previously in demographic analyses. In this study, the life table data of this mite fed on Le. squarrosulus were collected at 25, 30, and 35 °C and analyzed by using the age-stage, two-sex life table. The standard errors of population parameters were estimated by using the bootstrap technique (200,000 bootstraps). At 25, 30, and 35 °C, females started reproduction at ages 9, 5, and 3 d, respectively; the net reproductive rates (R₀) were 192.27, 253.81, and 234.11 offspring. Due to their rapid development and high fecundity, the r values were as high as 0.4189, 0.8653, and 1.0892 d⁻¹ at 25, 30, and 35 °C, respectively. Computer projection indicated that the mushroom mites Lu. perniciosus is capable of a threefold daily increase at 35 °C.

Xenorhabdus stockiaePB09 bacterium has been shown to exhibit antifungal activity against several plant pathogens. To improve its efficacy, the optimization of the nutritional components in culture media was performed. The medium components that have significant effects on antifungal activity ofX. stockiaePB09 were initially identified using a fractional factorial design. Response surface methodology and central composite design were then used to create a model for optimizing the levels of carbon, nitrogen, and mineral sources that maximize antifungal activity ofX. stockiaePB09. After that, the suitable carbon, nitrogen, and mineral sources were selected and adjusted by the second-order polynomial regression model, which predicted that 98.62% of antifungal activity could be obtained when the medium contained sucrose, yeast extract, NaCl, and K₂HPO₄at 3.24, 23.71, 5.46, and 2.73 g/L, respectively. Laboratory verification of this recipe resulted in the antifungal activity at 97.95% in the shake flask experiment after 48-hour cultivation, which was significantly 27.22% higher than that obtained by using the TSB medium. In addition,X. stockiaePB09 cultured in the verified recipe by using 5 L fermenter could effectively inhibit the mycelial growth ofPhytophthorasp.,Rhizoctonia solani,Pythiumsp., andFusarium oxysporum. This study demonstrated that the RSM and CCD were shown to be valuable tools for optimizing the culture medium that maximize the antifungal activity ofX. stockiaePB09.