Predation Of Four Species Ladybird Beetles Upon Spodoptera Frugiperda Eggs And Larvae

Ladybugs are a class of excellent predatory natural enemies that can prey on aphids,white flies,lepidopteran eggs,and young larvae and other agricultural and forest pests,and play an important role in biological control.Spodoptera frugiperda is a major outbreak pest in the worl d.Since it invaded our country in 2019,it has spread rapidly and seriously threatened the prod uction of corn and other food crops in my country.In order to control the damage of Spodopte ra frugiperda,timely excavation of native dominant natural enemies and evaluation of their pot ential for pest control have important practical guiding significance for the long-term sustainable management of Spodoptera frugiperda.Studies have shown that ladybugs can prey on Spodopt era frugiperda eggs and larvae,etc.To evaluate the control efficacy of Harmonia axyridis Palla s、Coccinella septempunctata、Hippodamia variegate Goeze and Propylaea japonica Thunberg a dults against Spodoptera frugiperda（J.E.Smith）,The predatory function of H.axyridis、C.septe mpunctata、H.variegate and P.japonica adults and larvae to S.frugiperda eggs、1^st and 2^nd in star larvae,and mutual interference of four ladybugs adults were tested in laboratory.The results are follows:1.Predatory effect of H.axyridis on S.frugiperdaThe functional responses of H.axyridis to S.frugiperda belonged to HollingⅡtype.The pr edatory capacity（a/Th）of 2^nd instar larvae of H.axyridis to S.frugiperda is as follows:eggs（136.285）>1^st instar larvae（44.984）;The predatory capacity（a/Th）of 3^nd instar larvae of H.axyridis to S.frugiperda is as follows:eggs（446.961）>1^st instar larvae（168.365）>2^nd instar lar vae（68.929）;The predatory capacity（a/Th）of 4^th instar larvae of H.axyridis to S.frugiperda is as follows:eggs（821.704）>1^st instar larvae（492.557）>2^nd instar larvae（103.997）;The predatory capacity（a/Th）of H.axyridis adults to S.frugiperda is as follows:eggs（614.443）>1^st instar larv ae（461.653）>2^nd instar larvae（87.440）;The predation of H.axyridis was strongly affected by int raspecific interference.2.Predatory effect of C.septempunctata on S.frugiperdaThe functional responses of C.septempunctata to S.frugiperda belonged to HollingⅡtype.The predatory capacity（a/Th）of 2^nd instar larvae of C.septempunctata to S.frugiperda is as fol lows:eggs（51.916）>1^st instar larvae（35.448）;The predatory capacity（a/Th）of 3^nd instar larvae o f C.septempunctata to S.frugiperda is as follows:eggs（149.757）>1^st instar larvae（149.472）>2ⁿdd instar larvae（37.093）;The predatory capacity（a/Th）of 4^th instar larvae of C.septempunctata to S.frugiperda is as follows:eggs（632.517）>1^st instar larvae（370.120）>2^nd instar larvae（56.129）;Th e predatory capacity（a/Th）of C.septempunctata adults to S.frugiperda is as follows:eggs（602.918）>1^stt instar larvae（280.653）>2^nd instar larvae（44.312）;The predation of C.septempunctata was strongly affected by intraspecific interference.3.Predatory effect of H.variegate on S.frugiperdaThe functional responses of H.variegate to S.frugiperda belonged to HollingⅡtype.The predatory capacity（a/Th）of 2^nd instar larvae of H.variegate to S.frugiperda is as follows:eggs（31.674）>1^st instar larvae（30.085）;The predatory capacity（a/Th）of 3^nd instar larvae of H.varieg ate to S.frugiperda is as follows:1^st instar larvae（111.604）>eggs（109.344）>2^nd instar larvae（27.200）;The predatory capacity（a/Th）of 4^th instar larvae of H.variegate to S.frugiperda is as fol lows:1^st instar larvae（314.146）>eggs（289.975）>2^nd instar larvae（61.035）;The predatory capacity（a/Th）of H.variegate adults to S.frugiperda is as follows:1^st instar larvae（269.93）>eggs（199.060）>2^nd instar larvae（72.575）;The predation of H.variegate was strongly affected by intraspeci fic interference.4.Predatory effect of P.japonica on S.frugiperdaThe functional responses of P.japonica to S.frugiperda belonged to HollingⅡtype.The pre datory capacity（a/Th）of 2^nd instar larvae of P.japonica to S.frugiperda is as follows:1^st instar larvae（23.280）>eggs（20.786）;The predatory capacity（a/Th）of 3^nd instar larvae of P.japonica to S.frugiperda is as follows:1^st instar larvae（92.491）>eggs（47.555）>2^nd instar larvae（12.362）;The predatory capacity（a/Th）of 4^th instar larvae of P.japonica to S.frugiperda is as follows:eggs（200.746）>1^stt instar larvae（199.921）>2^nd instar larvae（31.517）;The predatory capacity（a/Th）of P.japonica adults to S.frugiperda is as follows:eggs（196.290）>1^st instar larvae（138.829）>2^nd in star larvae（38.886）;The predation of P.japonica was strongly affected by intraspecific interferen ce.