Management Of The Whitefly Bemisia Tabaci With Physical Control Methods And Plant-mediated Support System

Bemisia tabaci(Hemiptera: Aleyrodidae)is an important worldwide-distributed agricultural pest.B.tabaci is a species complex with at least 44 cryptic species,of which two global invasive species Middle East-Asia Minor 1(MEAM1)and Mediterranean(MED)are particularly damaging.With the increase of whitefly’s resistance against chemicals and people awareness on environmental protection and food safety,the development and utilization of non-chemical control methods such as physical control and biological control for B.tabaci are arousing.Plant-mediated support system can protect natural enemies or trap pests by introducing some special plants into target plant areas.In this paper,some physical control methods and plant-mediated support systems were studied to explore their potential in whitefly control.Specific content and research results are as follows:(1)Combining an insect-proof net and yellow sticky traps to control B.tabaci in pepper seedlings.The size of net holes of 40-,60-,and 80-mesh nets were measured respectively.The proportion of the whitefly Bemisia tabaci and the parasitoid Eretmocerus hayati that could go through the nets were checked indoors.The results showed that 70% whiteflies were stopped whereas more than 90% parasitoids could go through the 60-mesh nets successfully.Whitefly on pepper seedlings could be effectively reduced by physical control meathods by hanging yellow sticky traps and covering 60-mesh insect-proof net.The number of eggs and nymphs of whitefly on pepper seedlings under physical control were significantly lower than that without any other control means.Moreover,the pesticides usage can reduced 50%-75%.(2)The attractiveness and repellence of two special odorant plants to B.tabaci were tested.Nicotiana benthamiana has potential as a trap plant to control whitefly.However,the preferecne of whitefly to N.benthamiana varies with the cryptic species of whitefly and pepper varieties.As for MEAM1 or MED,compared with Capsicum annuum(Hangjiao 1 and Zhengda 119),whitefly showed higher preference to N.benthamiana.Whiteflies initiatelly introduced in pepper can disperse to N.benthamiana.After 48 h,the number of whiteflies on both plants showed no significant difference.However,few whiteflies initiately introduced in N.benthamiana dispersed to pepper.The seedling of rosemary showed no attractiveness or repellence to whitefly.It needs further study for the effectiveness of rosemary varieties and growth stage.(3)The construction of a banker plant system: cotton-indigenous cryptic species of B.tabaci-Eretmocerus hayati for the control of B.tabaci.Cotton is a proper host for both indigenous and invasive B.tabaci.The suitability of the indigenous cryptic species of B.tabaci to four common greenhouse crops,i.e.,tomato,cucumber,eggplant and pepper were screened.For tomato,Asia 1 showed the lowest fitness;Asia II 6 was the least suitable cryptic species for eggplant;whereas for pepper,both the indigenous cryptic species Asia II 7 and invasive cryptic species MEAM1 had low fitness.There was no difference in the performance of the tested cryptic species on cucumber.A parasitic experiment of E.hayati was carried out,and it was found that the parasitoids could parasitize Asia 1,Asia II 7 and MEAM1 indiscriminately.Therefore,a banker plant system cotton-Asia II 7-E.hayati was constructed for the control of B.tabaci on pepper and tested in the laboratory.The results showed that the banker plant system could provide E.hayati continuously,and had the potential to effectively control whitefly after reasonable design and optimization.