Occurrence dynamics of Monolepta hieroglyphica and Harmonia axyridis in corn fields with different straw returning methods
To clarify the occurrence dynamics of Monolepta hieroglyphica in maize fields under different straw returning methods in Qiqihar of Heilongjiang Province,we used yellow sticky traps to monitor the pest and also the main natural enemy insects.The experiments performed in 2021 and 2022 showed that there were differences in the trapping peak and total catches of the four treatments:corn straw burying and returning to the field,straw crushing-and-mixing returning to the field,straw covering and returning to the field,and straw removal.The number of trapped insects was the highest in the straw crushing-and-mixing returning treatment,which was significantly higher than that of straw burying and returning and straw removal control.However,there was no significant difference between crushing-and-mixing returning and straw cover returning treatment.The yellow sticky traps mainly caught Harmonia axyridis,and there were no significant differences in the amount of H.axyridis trapped among the four straw returning treatments.