Diversity And Population Dynamics Of Pests And Their Natural Enemies In The Colored Oil-seed Rape

Natural enemies,as a key link of biological control,can effectively regulate the insect population density.In this paper,the diversity and population dynamics of pests and their natural enemies in the whole growth period of rapeseed were evaluated by investigation and traps under the background of different colors of rapeseed,and the influence of dominant natural enemies species on pests and the influence of different color(red,peach,yellow,purple,orange and white)on pests and their natural enemies was analyzed.The main results were as follows:1.Main pest species and richness of different color rapeAccording to a two-year survey in the North-Nan Chang Ecological Park of Jiangxi Province from 2020 to 2022,there were 9 major pests in the park,including hemiptera aphids and leafhoppers,Chromatomyia horticola,Plutella xylostella,Pieris canidia and Pieris rapae,Coleoptera phyllopterans and ricochets,and mollusc slugs.The aphid(turnip aphid and peach-potato aphid)and leaf miner accounted for more than 90% of the total pests,and the main dominant species in rape were stable in two years.There was no significant difference in pest richness among different color rapeseed.2.Community structure of natural enemies under different flower color rapeseedA total of 1 04 species and 11105 individuals of natural enem ies were captured from 2020 to 2022,among which spiders accounted for 50.73%,carabids accounted for 18.89% and staphylinid s accounted for 30.38%.Among them,the spiders are mainly in the family Linyphiidae and the family Lycosidae,the carabids are mainly in the genus Bembidion,the Dyschirius ordinatus,Amara congrua and the main staphylinid s are mainly in the subfamily Aleocharinae and the subfamily Oxytelinae.The diversity and richness of natural enemies on rape in two years showed that th ere were significant differences in richness and diversity of natural enemies under different color rape in 2021-2022.There was no significant difference in diversity and richness between two years.3.Population dynamics of pests and natural enemies in r apeseed with different flower colors during growthThe population numbers of pests and natural enemies in different flower colors of rapeseed in 2020-2022 at different times showed that the pests had two peak outbreak periods around December and from March to April of the next year,while the number of natural enemies was low in the early period,and also had a peak period around March to April of the next year.The population dynamics showed that the hostile pests had obvious inhibition effect.Some pests and natural enemies had significant differences under different color rapeseed in a certain period of time,while the population dynamics of total pests and natural enemies had no obvious rules under different color rapeseed.4.Comparison of insect pests and natural enemies at different growth stages of rape with different colorBy comparing the seedling stage,bud bolting stage,flowering stage and horn fruit development and maturity stage of rape from 2020 to 2022,it is concluded that there are significant differences in the pests in the first year at the flowering stage,and significant differences in the natural enemies in the second year.It can be concluded that there are significant differences in the occurrence amount of pests and natural enemies under different color rape at the flowering stage.In the first year,the pests of red rapeseed were significantly higher than those of other five color rapeseed,and the difference was mainly related to the population of leaf mi ners in rapeseed.In the second year,there was no significant difference in the total number of natural enemies of rapeseed,but there were significant differences in the total number of natural enemies of rapeseed under orange rapeseed than that under pe ach and purple rapeseed.The main reason may be that the synergistic effect between natural enemy communities was greater than the antagonistic effect...