Study On The Control Effect Of The Southern Stink Bug Carrier Plant System On Tea Stick Thrips And Tea Aphid

As an important economic crop,tea plants were prone to infected by small pests such as Toxoptera aurantii,Dendrothrips minowai,Empoasca onukii,which has seriously threatened the quality and yield of tea.Chemical control may cause residues and food safety problems.As an open rearing unit of natural enemies,banker plant system is increasingly used for pest control in greenhousees and fields.Orius strigicollis are among the most effective predators of thrips,aphids,leafhoppers,and other small pests,and has great application value in agriculture.Establish a banker plant system is one of the effective methods to improve the control efficacy of O.strigicollis.In this study,we developed a non-crop banker plant system.In this system,we used the polyphagous predator O.strigicollis as the biocontrol agent,the black bean aphid Aphis fabae(Scopoli)as an alternative food and the faba bean Vicia faba L.as the banker plant to support the predator in controlling the tea pests.Fitness of A.fabae on tea plants and faba bean was evaluated to determine its host specificity.Moreover,a laboratory experiment was performed to estimate the size of the initial population of A.fabae required to maintain O.strigicollis under conditions without the pest.Finally,the control efficacy of the banker plant system on T.aurnantii,D.minowai and Empoasca onukii were compared with that of direct release of O.strigicollis in laboratory and field.The main results are summarized as following:1.Efficiency of O.strigicollis banker plant system for the control of T.aurnantii and D.minowai aloned(1)Efficiency of O.strigicollis banker plant system for the control of T.aurnantiiFirstly,A.fabae was introduced on the tea plant and they all died within 9 days,while the number of A.fabae on V.faba kept increasing,indicating that A.fabae cannot survive on tea plants and are safe to use as an alternative prey for O.strigicollis to control tea pests.The control efficacy of the banker plant system was then compared with that direct release of O.strigicollis to determine whether it was effective in controlling Toxoptera aurnantii.The A.fabae was introduced into the V.faba seedlings and the adult female O.strigicollis was introduced 24 h later,and the Toxoptera aurnantii were introduced 10 days later.The result showed that the control efficacy of the banker plant system was higher than that of direct release of O.strigicollis in controlling Toxoptera aurnantii within 35 days.The highest control efficacy of the banker plant system for Toxoptera aurnantii was 92.16% after 21 days,while the direct release of the O.strigicollis was only 72.25%,showing the banker plant system could control Toxoptera aurnantii efficiently and the control efficacy was better than that of direct release of O.strigicollis in the early stage.(2)Efficiency of O.strigicollis banker plant system for the control of D.minowaiThe initial population size of the alternative prey required to maintain the population of O.strigicollis in the absence of the target pest was first explored.With the same number of alternative preys on the tea plants,different population bases were obtained after 24 h,48 h and 72 h of reproduction by the alternative prey,and it was found that the population size of A.fabae after 72 h of reproduction could supply the feeding of the O.strigicollis and maintain its population size,which was more suitable than that of 24 h and 48 h.Next,A.fabae were introduced on V.faba seedlings for 72 h,followed by the adult females of O.strigicollis,and 10 d later by D.minowai.The control efficacy of the banker plant system was compared with that of direct release of O.strigicollis on D.minowai,it was found that the control efficacy of the banker plant system on D.minowai was higher than that of direct release of O.strigicollis,up to 100%,while the control efficacy of the direct release of O.strigicollis on D.minowai was up to 68.55%,and there was a significant difference between the two treatments(p< 0.05).2.Efficiency of O.strigicollis banker plant system for the control of T.aurnantii and D.minowai mixed.The expriments method was the same as 1 of D.minowai,except that the number of T.aurnantii and D.minowai introduced were 25 respectively.The results showed that the highest control efficacy of the O.strigicollis banker plant system on T.aurnantii and D.minowai was 92.25% and 85.36% respectively,while the highest control efficacy of direct release of O.strigicollis on T.aurnantii and D.minowai was 72.80% and 70.82% respectively.The results showed that the banker plant system was more effective in controlling the pest than the direct release of O.strigicollis,both for T.aurnantii and D.minowai alone or mixed.3.Evaluation of the control efficiency of O.trigicollis banker plant system in fieldIn the field,banker plant layouts were divided into three types: strip,block and dot,and direct release of O.strigicollis and control plots were also set up,with five treatments.The results showed that banker plants layout(strip,block and dot)had no significant affect on the control efficiency of the banker plant system in the field experiment;both the banker plant system and the direct release of O.strigicollis can effectively control E.onukii,and the highest control efficacy was about 90%,but there was no significant affect on the control of T.aurnantii and D.minowai.In summary,showing both the banker plant system and the direct release of O.strigicollis can be used for the control of tea pests.However,the control efficiency of the banker plant system was better than that of the direct release.