Sex Pheromone Monitoring Of Main Maize Pests And The Resistance Of Maize Varieties To Insect Pests

The sex pheromone lures were used to monitor the occurrence of main lepidopteran pests,Athetis lepigone, Ostrinia furnacalis, Conogethes punctiferalis, Helicoverpa armigera on maize. The insect pests on 47 maize cultivars and inbred lines were investigated to identify the maize resistance to different pests, and the dominant species of pests and their natural enemies and the community characters on 47 maize cultivars and inbred lines were analysized.The main results were as follows.1. Sex pheromone monitoring of lepidopterous pestsOverwintering generation A. lepigone adult occurred in the early April to early May, the first generation in the middle June to early July, the second generation in the mid-July to early August, and the third generation in the mid-August to the mid-September. Overwintering generation O. furnacalis adult occurred in the middle of May to the end of June, the first generation in the early to middle of July, the second generation in the middle of August to middle of September. Overwintering generation C. punctiferalis adult occurred in the early May to mid-June, the first generation in late June to late July, the second generation in August and the third generation in September. H. armigera adult occurs three generations, the first,second and the third generation occurred in the middle to late of June, the middle to late July and the middle to August, respectively.2. The resistance of different maize varieties to insect pestsThe aphid(or borer) indices were used to valuated the resistance of 47 maize cultivars and inbred lines to 6 species of pests, Aphis gossypii, Rhopalosiphum maidis, R. padi, O.furnacalis, C. punctiferalis, H. armigera. “Jiyu 6, Liansheng 216, Shihai 828” showed highest resistance level to Aphis gossypii Glover; “Denghai 3737, Jiyu 6, Liansheng 188, Longping206, Shannong 085, Xixinghuangnuo 958, Ziyu 308” showed highest resistance level to R.maidis; “Liansheng 216, Xixinghuangnuo 958” showed highest resistance level to R. padi;“Delinong 988, Qidan 128, Ludan 9066, Jihai 13, Liyu 86, Longping 206, Ludan 818, Shihai718, Xianyu 335” showed highest resistance level to O. furnacalis; Most maize varieties displayed the mid-level resistance to C. punctiferalis; “Dika 517, Jinhai 13, Liansheng 216,Liaoyu 23, Nuoda 1, Shihai 828, Xixinghuangnuo 958” showed highest resistance level to H.armigera.3. The population dynamics of the main maize pests and their natural enemiesThe population dynamics of R. maidis and A. gossypii were similar, rising after the beginning of July and peaked in the middle of September; Rhopalosighum padi occurred inthe middle of August at the beginning, peaked in the middle of September; O. furnacalis began to damage the maize in early July, its population increased in the early of August and peaked in the end of August; H. armigera population peaked in the middle of July; C.punctiferalis peaked from in the end of August to in the early of September.The population dynamics of natural enemies, hoverflies, parasitic wasps of aphids,ladybird beetles and spiders, were similar, peaking in the middle of September; lacewings peaked in the early August; predacious bugs peaked in the late of July.4. The components and the dominant species of maize arthropod communitiesThe community of arthropod in maize field was made up of sap-sucking pests,leaf-feeding/borers pests and their natural enemies. There were 43 species of pests and 35 natural enemies. The sap-sucking pests which had the maximum proportion of individual number in the pest community were aphids and lepidopterous pests. The lace wings,predacious bug, ladybirds and spiders were in higher number in natural enemy community.The dominant pest species is similar among the different maize varieties. The dominant pest species in arthropod community in maize field included Rhopalosiphum maidis, Aphis gossypii, Rhopalosighum padi, Ostrinia furnacalis, Helicoverpa armigera and Conogethes punctiferalis. The dominant natural enemy species included ladybirds, spiders, Chrysoperla nipponensis and Orius minuius.5. Analysis of community diversity characteristics in different maize varietiesThe research of community characteristic indices in the different maize varieties indicated that the community individual number and the ecological dominance on Jiyu 6,Denghai 3737, etc. with high resistance were less than that on other varieties, the community diversity and evenness of the maize cultivars were higher than that on other varieties. The community individual number and the ecological dominance on Delinong 988, Shengrui 999 etc. with high susceptibility were higher than that on other varieties, but the community diversity and evenness were much less.6. The food web of arthropod community in maize fieldAccording to the predation and parasitism of between the pests and their natural enemies,the food web of arthropods in maize field was tentatively constructed. In the context of food web in maize field, aphids and their natural enemies were abundant and play the important role.