Effects of tobacco intercropping with fresh corn on the main species of field pests and their occurrence dynamics

【Objective】 To explore the effects of tobacco intercropping with fresh corn on the main species of field pests and their occurrence dynamics， which could provide theoretical basis for the formulation of comprehensive pest control strategies in the tobacco-grain integrated planting area.【Method】 Taking Xinhua Village， Miaojie Town， Weishan County， Dali Prefecture， Yunnan Province as the experimental site for intercropping fresh corn in the late stage of tobacco growth， a systematic investigation was conducted on the types and occurrence dynamics of major pests using visual inspection， net scanning， and sexual trapping methods. The types， quantities and dynamic changes of the main pests in tobacco-fresh corn intercropping fields， as well as in tobacco monoculture fields and fresh corn monoculture fields during the same period were compared.【Result】 Under the intercropping of tobacco and fresh corn， the main types of tobacco pests were Myzus persicae， Nesidiocoris tenuis， Trialeurodes vaporariorum ， and Spodoptera litura； the main types of fresh corn pests were Rhopalosiphum maidis， Spodoptera frugiperda， and Spodoptera litura. The occurrence dynamics of Myzus persicae were bimodal in both tobacco monoculture and tobacco-fresh corn intercropping fields， with a higher occurrence in tobacco-fresh corn intercropping fields than tobacco monoculture fields. The occurrence dynamics of Nesidiocoris tenuis were bimodal in tobacco-fresh corn intercropping fields and tobacco monoculture fields， with similar occurrences in the two modes of fields.The occurrence dynamics of Spodoptera litura were bimodal in tobacco-fresh corn intercropping fields and unimodal in tobacco monoculture fields， and the occurrence of tobacco-fresh corn intercropping fields was higher than that of tobacco monoculture fields. The occurrence dynamics of Spodoptera frugiperda adults in monoculture corn fields and tobacco-fresh corn intercropping fields were both unimodal patterns， with lower occurrence in tobacco-fresh corn intercropping fields compared to monoculture corn fields. The occurrence dynamics of Rhopalosiphum maidis were both unimodal in tobacco-fresh corn intercropping fields and monoculture fresh corn fields， with higher occurrence in tobacco-fresh corn intercropping fields compared to monoculture fresh corn fields. The occurrence dynamics of Trialeurodes vaporariorum were both unimodal in tobacco monoculture fields and tobacco-fresh corn intercropping fields， with higher occurrence in tobacco monoculture fields compared to tobacco-fresh corn intercropping fields.【Conclusion】 The accumulated insect quantities of Myzus persicae， Spodoptera litura， Spodoptera frugiperda， and Rhopalosiphum maidis are larger on tobacco-fresh corn intercropping fields than monoculture fields， special attention should be paid during pest control. The population densities of Trialeurodes vaporariorum and Nesidiocoris tenuis on tobacco-fresh corn intercropping fields decrease， indicating that intercropping fresh corn after tobacco can effectively regulate the subpopulation of pests and reduce their occurrence. Green control measures can be implemented based on the main types and occurrence dynamics of pests.