Effects of temperature and photoperiod on parasitism of Microplitis tuberculifer on Spodoptera frugiperda.
Spodoptera frugiperda is one of the major agricultural pests in the world. Previous research showed that Microplitis tuberculifer can effectively control S. frugiperda. To further optimize the control efficiency, the effects of temperature and photoperiod on parasitization of S. frugiperda by M. tuberculifer and the development of offspring wasps were investigated. The results showed that under 10L:14D and 14L:10D photoperiod conditions, the parasitism of M. tuberculifer was better at 20°C, 24°C and 28°C than at 16°C and 32°C; at the former temperatures, the cocooning rate was >70%, the deformity rate was <6%, and the eclosion rate was >60%. The developmental duration (egg-larva stage, pupal stage, and adult stage) of M. tuberculifer was significantly shortened and cocoon weight, significantly reduced, with the increase of temperature. Diapause was induced at 16°C and 10L:14D. At 28°C, photoperiod had no significant effect on the parasitism rate (>70%), deformity rate (<4%), development duration, and cocoon weight. At 16°C, diapause was induced when the photophase was less than 12 h. Therefore, the optimum temperatures for the growth of M. tuberculifer range wide, the parasitization of S. frugiperda varies little in the range of 16°C to 32°C, and the optimum temperatures for parasitism and growth of M. tuberculifer range from 20°C to 28°C. The photoperiod has little effect on the parasitization of S. frugiperda. At 28°C, the photoperiods ranging from 8L:16D to 16L:8D all show high control of young S. frugiperda larvae.