Evaluation Of The Population Fitness And Biocontrol Potential Of The Caterpillar Stink Bug Against The Tea Silver Loope

Scopula subpunctaria（Herrich-Schaeffer）（Lepidoptera:Geometridae）is a leaf-eating pest in tea plantations.It occurs in tea plantations for 6 generations per year,and is more common with larvae feeding on tea leaves,which can easily cause serious economic losses in tea plantations.The control of S.subpunctaria in production is based on chemical control,and organic tea plantations use Nucleopolyhedrosis virus（NPV）to control S.subpunctaria when it occurs,but the study of using natural enemy insects to control S.subpunctaria has not been reported.Arma chinensis（Fallou）（Hemiptera:Pentatomidae）is a predatory natural enemy and the predation evaluation,feeding impact and behavioral observation of using A.chinensis to control pests such as Spodoptera litura（Fabricius）,Spodoptera exigua（Hübner）,Plutella xylostella（Linnaeus）and Spodoptera frugiperda（J.E.Smmith）have been carried out.The large-scale field release of A.chinensis is also being carried out gradually.In order to better promote the application of A.chinensis for biological control of Lepidoptera pests in tea plantations and ensure the quality and safety of tea,this study took the main pest of tea plantations in Guizhou,S.subpunctaria,as the research object,and used the regular prey of Mythimna seperata（Walker）,as the reference,and evaluated the role of S.subpunctaria on the establishment of A.chinensis populations,as well as the population suitability and biological control potential of A.chinensis on S.subpunctaria using the age-stage,two-sex life table method,in an attempt to elucidate the feasibility of releasing A.chinensis in tea plantations for the control of S.subpunctaria.The results of this study are as follows:1.Life table study of S.subpunctaria.S.subpunctaria can complete its life history by feeding on Fudingdabai tea.The eggs of S.subpunctaria were hatched in 7days,the preadult stage was 32.86 days,the adult stage was 25.36 days,the average number of days of egg laying for female adults was 19.18 days,and the egg production was 200.64 eggs.From the population parameters,the intrinsic rate of increase of S.subpunctaria population was 0.0951 and the mean generation time was45 days.2.The daily maximum predation of A.chinensis.By measuring the maximum daily predation of the 24-h starved A.chinensis on the 3rd instars of S.subpunctaria and M.seperata,we found that their predation on these two pests gradually increased with the growth of their ages.However,from the maximum daily predation of the same stage,the predation on M.seperata was significantly more than that on S.subpunctaria.3.Life table studies on the predation of different prey by A.chinensis.Both A.chinensis could complete their life histories when feeding on S.subpunctaria and M.seperata respectively,but the developmental periods of A.chinensis were different at each stage.In terms of developmental parameters,there were no significant differences between the egg stage,1st instar,2nd instar,preadult stage,total preoviposition period,Oviposition days,and mean fecundity when A.chinensis feeding on the two pests.In terms of population parameters,there were also no significant differences between the Intrinsic rate of increase（r）,finite rate of increase（λ）,net reproduction rate（R₀）,and mean generation time（T）of these two populations of A.chinensis.However,there was a significant difference between the adult life duration of female（73.20 days）and male（63.38 days）when A.chinensis were feeding on S.subpunctaria and the adult life duration of female（85.59 days）and male（79.37 days）when A.chinensis were feeding on M.seperata.The male to female sex ratios of the two populations of A.chinensis showed that the proportion of females in the entire population was greater in A.chinensis population feeding on S.subpunctaria than in A.chinensis population feeding on M.seperata.4.A study of predation rates of different prey species in A.chinensis.The predation of A.chinensis increased with the growth of developmental stages,and there was a significant difference between the predation of A.chinensis on S.subpunctaria and M.seperata at each age.In addition,the total stage predation of adult A.chinensis was significantly higher than that of their respective preadult stages when feeding on these two pests,and the adult females were significantly higher than the adult males.5.Computer simulation of the control potential of A.chinensis.When five pairs of adult A.chinensis intervened,the pest populations developed from 1000 3rd instar S.subpunctaria larva were consumed by A.chinensis population on day 17.