Dynamic and correlation of major pests with natural enemies and response to climatic factors in alfalfa fields in Ningxia
In order to investigate the relationship between major pests and natural enemies in alfalfa fields,two alfalfa fields with different field treatments in Ningxia were selected as the study sites. Field surveys were carried out by using the 100-branch method,the swept-net method and the yellow disk method to gather data on pest populations,predatory natural enemies,and parasitic wasps. The α-diver-sity indices of natural enemies were calculated,and correlation analyses of the pests,natural enemies and climatic factors were performed. The results showed that the 100-branch pest population density peaked in mid-June and late July 2022 in the Yuanlinchang area,while the highest total pest population was observed on August 11 in the Maosheng area. A total of 679 predatory natural enemies from nine species and 284 parasitic wasps of 38 species were collected in Yuanlinchang;540 predatory natural en-emies from eight species and 122 parasitic wasps from 33 species were collected in Maosheng. The Shannon-Wiener diversity index,Simpson dominance index and Margalef richness index of natural en-emies were all highest in June,significantly higher than in April-May and July in Yuanlinchang. Con-versely,in Maosheng,the Shannon-Wiener diversity index,Simpson dominance index and Pielou even-ness index of natural enemies were all lowest in June. Margalef richness index was highest in Septem-ber. Pea aphid Acyrthosiphon pisum was significantly positively correlated with Hippodamia variegata in Yuanlinchang,while A. pisum was significantly positively correlated with Orius sauteri,and Pro-pylea japonica in Maosheng. Additionally,the number of dominant+common predatory natural enemies was significantly positively correlated with air temperature,while the number of pea aphids was signifi-cantly negatively correlated with the lowest air humidity in the Yuanlinchang area. The number of thrips was significantly positively correlated with the average and lowest air temperatures in the Maosheng area,and the number of alfalfa spotted aphids Therioaphis trifolii was significantly negatively corre-lated with the highest humidity.
万方数据
维普
