Integration of endemic natural enemies and Bacillus thuringiensis to manage Brassica pests in the Democratic Peoples Republic of Korea
Brassica crops account for over half the total vegetable production in the Democratic Peoples Republic of Korea(DPRK). The crops are attacked by a complex of insect pests and their combined actions seriously threaten national food security. In recent years the abundance of Plutella xylostella(L.)has increased dramatically and,together with Pieris rapae(L.),it represents the key constraint to Brassica cmp production.On co-operative farms,pests are managed by scheduled application of broad spectrum insecticides and there is little attempt to conserve or utilize endemic natural enemies. The natural enemy complexes attacking P.xylostella and P.rapae on three co-operative farms in the south west of DPRK were studied.Plutella xylostella was attacked by the hymenopteran parasitoids Cotesia plutellae Kurdjumov,Oomyzus sokolowskii Kurdjumov and Diadromus collaris Gravenhorst.and P.rapae was attacked by the hymenopteran parasitoids Cotesia glomeratus L.,Cotesia rubecula Marshall and Pteromalus puparum L.and unidentified tachinid parasitoids in the genus Exorista.Generalist foliar and epigeal predators included various Coleoptera,Aranae and Chrysopidae.On co-operative farms in 2004-2005,respective larval and pupal parasitism rates reached 30％and 36％in P.xylostella and 38％and 37％in P.rapae.However,natural enemy exclusion experiments indicated that the impact of endemic natural enemies on P.xylostella populations was very low. In a preliminary step towards the introduction of conservation biological control strategies,field experiments compared current pest management practice with pest threshold-based interventions using commercial formulations of Bacillus thuringiensis(Bt). The Bt-natural enemy strategy significantly increased crop yields and the impact of natural enemies on pest populations.However,even under the threshold based Bt regimes,natural enemy impact remained relatively low. The results are discussed in relation to current agricultural circumstances in DPRK and recommendations for improving biological control and more effective management of key Brassica pests are made.
Michael J.Furlong Kim Hak Ju Pak Wi Su Jo Kwang Chol Ri Chang Il Myron P.Zalucki
School of Integrative Biology,University of Queensland,St Lucia,Queensland 4072,Australia Sariwon Agricultural University,Sariwon,DPRK Plant Protection Institute,Korean Academy of Agricultural Sciences,Pyongyang,DPRK Pyongyang Agricultural University,Pyongyang,DPRK
国际会议
北京
英文
287-302
2006-10-24（万方平台首次上网日期，不代表论文的发表时间）