The Fitness of Mass Rearing Food on the Establishment of Chrysopa pallens in a Banker Plant System under Fluctuating Temperature Conditions

The predatory lacewing, Chrysopa pallens, a generalist predator in the field, plays an important role in sustainable, integrated pest management strategies by allowing a reduction in the use of chemical pesticides. However, the effect of mass rearing food, i.e., eggs of the rice moth Corcyra cephalonica, on the establishment of C. pallens in a banker plant system in the field is unknown. Based on the age-stage, two-sex life table, and predation rate data of C. pallens ever cultured on the C. cephalonica eggs or the aphid Megoura japonica preying on Aphis craccivora under fluctuating temperature conditions in a greenhouse, we found that C. pallens could complete their development fed on A. craccivora regardless of the food used during culture. This suggests that rice moth eggs could be provided for the mass rearing of predatory lacewings without affecting their population development and biological performance in practical applications compared with lacewings cultured on aphids. This information can serve as a basis for the application of a banker plant system with the mass reared C. pallens in the field. Banker plant systems can be used to sustain a reproducing population of biological control agents (BCAs) within a crop, thus providing long-term pest suppression. The founder population of natural enemies in banker plant systems is usually mass-reared on factitious hosts. Thus, a better understanding of the population fitness and pest control performance of mass-reared BCAs in the field is crucial when developing integrated pest management (IPM) strategies. In this study, we determined the fitness of the generalist predator, Chrysopa pallens (Hemiptera: Chrysopidae) ever cultured on different food sources (i.e., mass rearing food, Corcyra cephalonica eggs, and aphid food, Megoura japonica) preying on Aphis craccivora in a banker plant system in a greenhouse based on Chi's age-stage, two-sex life table analysis method. The life tables and predation rate parameters of C. pallens were not significantly different between both treatments under fluctuating temperature conditions. Corcyra cephalonica eggs did not significantly weaken the performances of C. pallens in a Vicia faba-A. craccivora banker plant system compared to aphids. In conclusion, C. cephalonica eggs can be used for the mass production of C. pallens as the founder population in a banker plant system. Moreover, linking the life table data with the predation rate is an effective strategy for evaluating mass rearing programs in establishing banker plant systems.

Automated summary

The study demonstrates that the predatory lacewing, Chrysopa pallens, can complete development fed on A. craccivora, and using Corcyra cephalonica eggs for mass rearing does not affect their population development and biological performance, indicating that the eggs of C. cephalonica can be used for mass production of C. pallens in practical applications.