Cold acclimation enhances cold tolerance and storage capacity in Neoseiulus bicaudus (Acari: Phytoseiidae)

The predatory mite Neoseiulus bicaudus (Wainstein) (Acari: Phytoseiidae) is used against spider mites, whiteflies, and thrips. Knowledge of the cold acclimation and cold storage techniques for natural enemy biological control agents can promote their development and utilization. This study assessed the impact of cold acclimation on the cold tolerance of N. bicaudus. Then, a cold storage program for N. bicaudus was designed by implementing cold acclimation, followed by an evaluation of the impact of storage on the performance of N. bicaudus. After acclimation at temperatures ranging from 0 to 18 °C for a duration of 2 h to 7 d, the survival rate of mites significantly increased at low temperatures (-6 °C); The survival rate significantly increased to 90% after acclimating at 12 °C for 7 d. In addition, the supercooling point of mites significantly decreased when the acclimation temperature was below 0 °C. After cold acclimation, the survival time of N. bicaudus was 68.3 d and 60.5 d when kept at 9 °C and 12°C, respectively. The fecundity, longevity and predation capacity of female adults were unaffected by 30 d of storage at 12 °C. Furthermore, the storage did not affect the efficiency of N. bicaudus against spider mite Tetranychus turkestani Ugarov & Nikolskii (Acari: Tetranychidae). The process of cold acclimation significantly improved both cold tolerance and cold storage. Cold acclimation at 3 to 21 °C followed by 30 d of storage at 12 °C or 9 °C is recommended for maintaining the quality of N. bicaudus.