Study on the predation effects of Harmonia axyridis adults on nymphs of Psylla chinensis
[Objective]As a widely distributed natural enemy insect in northern China,Harmonia axyridis has good control effects on various forest and fruit pests.Scientific evaluation of its control against the important pest Psylla chinensis in pear regions of Northern China is of great practical significance for the protection and utilization of H.axyridis.[Method]Low-instar(1-2 instars)and high-instar(3-5 instars)nymphs of P.chinensis with densities of 25,50,75,100,125,and150 heads/dish were set up in the laboratory to feed the adults of H.axyridi starved for 24 h.The predatory functional response and searching effect of H.axyridi adults on the young and old nymphs of P.chinensis were analyzed by measuring the daily predation of H.axyridis adults.[Result]The morphological characteristics of different instar nymphs of Psylla chinensis were significantly different.The predatory functional responses of H.axyridis adults to the early instar and late instar nymphs of P.chinensis fitted well with the Holling II-disc equation.And the predation amount of H.axyridis adults increased with the increase of the density of P.chinensis nymphs.The predation of adult ladybugs increased with the density of P.chinensis nymphs,with a maximum daily predation of 500 nymphs per day for young nymphs,which was twice that of older nymphs.The searching effect of H.axyridis adults on nymphs of P.chinensis decreased with the increase of nymph density.[Conclusion]Psylla chinensis nymphs could be effectively preyed on by H.axyridis adults.The predation effect on young nymphs is stronger than that on older larvae,providing a theoretical basis for the application of H.axyridis adults to control P.chinensis.
万方数据
维普
