Abstract:
Objective To investigate the predation potential of the natural enemies, Harmonia axyridis, to Spodoptera frugiperda.
Method The predation behavior of H. axyridis was observed in laboratory, and the predation abilities of H. axyridis adults and the 4th instar larvae to the 1st and 2nd instar larvae of S. frugiperda were evaluated.
Result The predatory behaviors of H. axyridis on S. frugiperda larvae included five behaviors of stationary, searching, testing, feeding and crawling. H. axyridis adult appeared three pairs of feet grasping its prey when preying on the 3rd instar larva of S. frugiperda. The predation function responses of H. axyridis adults and the 4th instar larvae to the 1st and the 2nd instar larvae of S. frugiperda were accorded with the Holling II model. For the 1st instar larvae of S. frugiperda, the maximum daily predation amounts of adults and the 4th instar larvae of H. axyridis were 196.08 and 161.29 individuals respectively, the rates of instantaneous attack were 1.390 6 and 1.451 4 respectively, and the handling time were 0.005 1 and 0.006 2 days respectively. For the 2nd instar larvae of S. frugiperda, the maximum daily predation amounts of adults and the 4th instar larvae of H. axyridis were 65.36 and 41.84 individuals respectively, the rates of instantaneous attack were 1.145 7 and 1.271 0 respectively, and the handling time were 0.015 3 and 0.023 9 days respectively. The predation abilities of H. axyridis adults to S. frugiperda larvae were stronger than those of the 4th instar larvae of H. axyridis.
Conclusion H. axyridis has certain potential control ability on S. frugiperda and can be used for the prevention and control of S. frugiperda.