| Laodelphax striatellus(Fallen)belongs to the Homoptera planthopper family and is an important agricultural pest.It affects the grain harvest mainly by sucking rice stalk juice,secreting honeydew,and spreading rice virus disease.It has been reported that the fungicide carbendazim stimulates reproduction of Laodelphax striatellus,while Jinggangmycin inhibits reproduction.This article is based on the effect of different treatments of fungicides Carbendazim and Jinggangmycin on the reproduction of Laodelphax striatellus.Through the observation records of the whole life cycle of the treated Laodelphax striatellus and determined the indexs related to insect nutrition and metabolism,it is clarified that the internal mechanism of the two opposite effects of mixed treatment or superimposed treatment of two fungicides on the reproduction of Laodelphax striatellus.The main research results include the following aspects.1.The effect of mixed fungicide treatment on the fecundity and physiological indexes of SBPH.The results showed that the fungicide treatments had different effects on the fecundity,body weight,body length and oviposition valve length of SBPH:the fecundity,body length and oviposition valve length of SBPH treated with JGM+CBM were 19.0%,9.6%and 32.1%higher than those of control treatment,respectively;The egg production,pre oviposition period,oviposition duration,body weight,body length and oviposition valve length of SBPH treated with JGM+CBM were 53.1%,40.0%,14.9%,31.5%,10.3%and 38.2%higher than those of JGM,respectively.The egg production,egg laying duration,female longevity,body weight and oviposition valve length of SBPH treated with JGM were lower 44.2%,19%,14.7%,29.3%and 11.1%than those oc control,respectively.When Jinggangmycin and carbendazim were mixed,and then Jinggangmycin(JGM+CBM+JGM)was sprayed,the fecundity,body weight and oviposition valve length of the planthopper were lower 33.9%,18.4%and 10.8%than those of control,but the pre oviposition period was higher 42.8%than that of control;The egg production,pre oviposition stage,body weight,body length and oviposition valve length of SBPH treated with JGM+ CBM+JGM were lower 80.0%,40%,21.1%,7.3%and 61.4%than those of JGM+CBM,but the egg laying duration and female longevity were higher 21.1%and 21.5%than those of JGM+CBM.In order to explore the causes,the indexes were measured from biological and physiological perspectives to explain the reasons for the reproductive effects of mixed fungicide treatment:The contents of ovarian protein,triglyceride and Vg expression in in S BPH treated with JGM+CBM were higher 23.9%,42.5%and 18.7%than those oc control,respectively,higher than 45.5%,95.2%and 86.7%,compared to JGM.The contents of ovarian protein,triglyceride and Vg expression in SBPH were lower 14.8%,26.9%and 36.4%,10.0%,27.7%and 43.9%than of those of control.The contents of ovarian protein,triglyceride and Vg expression in SBPH treated with JGM+CBM+JGM were lower27.4%,49.3%and 52.7%than that of JGM+CBM,respectively.2.Effects of silencing RPS30 and RPS36 on the fecundity of SBPH adult females treated by mixed fungicides.After transcriptome analysis,two interesting genes RPS30 and RPS36 were screened out,The expression of ribosomal protein small subunit 30 in SBPH treated by JGM+CBM+JGM was down-regulated compared to JGM+CBM.Compared to JGM group,the expression of ribosomal protein small subunit 36 for JGM+CBM+JGM group was up-regulated.In this paper,RNAi technology was used to study the role of RPS30 and RPS36 in the reproduction.The number of eggs laid by developed female adults following JGM+CBM+dsRPS30 treatment decreased by 73.6%,the number of pre oviposition decreased by 44.1%,the duration of oviposition shortened by 61.9%,and the longevity shortened by 42.0%compared to JGM+CBM+dsGFP.Compared to JGM+CBM +dsGFP treatment,JGM+CBM+dsRPS36 treatment reduced the number of eggs laid by 57.1%%,pre oviposition period by 47.1%,oviposition duration by 55.8%and life span by 39.1%.After the interference of the two genes,the biological and physiological indexes also changed.Compared to the negative control group,the body weight and body length decreased by 11.1%and 7.4%,respectively.The length of oviposition valve was significantly shortened by 36.4%.The content of protein and triglyceride in ovaries decreased by 58.2%and 71.2%respectively.Compared to the negative control group,the body weight and body length decreased by 5.2%and 5.8%,respectively.The length of oviposition valve was significantly shortened by 33.6%.The protein content and triglyceride content in ovaries were significantly decreased by 48.6%and 58.9%,respectively. |
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