| Sunflower is one of the important cash crops worldwide,and Bayannur City in Inner Mongolia is not only the most important sunflower production area in China,but also a serious damage area for sunflower pests such as Homoeosoma nebulellum and Frankliniella intonsa in our region.This experiment was conducted from July to September 2021 and from June to September 2022 in sunflower fields of Wuyuan County to investigate the diversity of insect communities and the population dynamics of Frankliniella intonsa in the fields,with the aim of gaining a comprehensive understanding of the taxa and numbers of beneficial and harmful insects in sunflower fields,clarifying the dynamics of flower thrips in sunflower fields,analyzing the causes of serious damage by flower thrips,determining the best control period,and providing scientific data support for the development of green prevention and control strategies for insect pests in sunflower fields.The main research results are as follows :1.The insect community structure of sunflower field was investigated by using the trapping method of martinet.13,632 insect specimens were collected from July to September 2021,and 119 families in 8 orders were identified.A mong them,46 families in Diptera,34 families in Hymenoptera,14 families in Coleoptera,11 families in Lepidoptera.The four orders accounted for 88.24%.In Diptera,the dominant groups are Sciaridae,Phoridae,Chloropidae,Ceratopo gonidae,Culicidae,Milichiidae,Anthomyiidae,Muscidae.In Hymenoptera,the dominant groups are Diapriidae,Mymaridae,Braconidae,Ichneumonidae,Megas pilidae,Scelionidae.In Lepidoptera,the dominant groups are Gracillariidae,No ctuidae,Pyralidae.In Coleoptera,the dominant groups are Anthicidae,Chrysom elidae,Coccinellidae.2.Diversity of ground arthropod communities in sunflower fieldsThe diversity of ground arthropod community in sunflower fields was investigated by ground traps.The survey results showed that there were significant differences in community diversity of ground arthropods in sunflower fields with different growth stages.3.Investigation of the dynamics of flower thrips population on sunflower leaves and flower discsThe results of field survey statistics and analysis showed that the vertical distribution of Frankliniella intonsa in sunflower plants showed the characteristics of upper layer > middle layer > lower layer.The peak number of Frankliniella intonsa on sunflower leaves and discs appeared in sunflower R4、R6 stage,with 319.7 heads/10 plants and 169 heads/10 plants,respectively.The spatial distribution patterns of Frankliniella intonsa populations in sunflower fields at all fertility stages showed aggregated distribution.4.Population dynamics of Frankliniella intonsa in sunflower fields under trap board monitoringThe population dynamics of Frankliniella intonsa in sunflower fields was investigated using the color plate trapping method.The results showed that the Frankliniella intonsa started to appear around June 19,2022,reached its annual peak around September 3,and moved out of the sunflower field around September 20.The results of color plates trapping at different times of the day showed that the peak of Frankliniella intonsa activity occurred from 12:00 to 14:00.5.Analysis of sunflower seed rust spot incidence and heat production rhythm of flower discsBy comparing the degree of seed rust spot occurrence in sunflower and oil sunflower under different cropping patterns,we found that there was a significant difference in the rate of seed rust spot in sunflower under intercropping patterns,which indicated that intercropping could reduce the incidence of sunflower seed rust spot to a certain extent.The results of heat generation rhythm of sunflower discs showed that the heat generation of sunflower discs in the thrips zone was more obvious before flowering,and the temperature of the discs reached the peak around 10:00 am.The heat generation of sunflower discs in the non-thrips zone was less obvious than that in the thrips zone. |
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