Evaluation Of Predation Efficiency Of Neoseiulus Pseudolongispinosus On Tetranychus Urticae

The two-spotted spider mites Tetranychus urticae(Acari: Trombidiformes: Tetranychidae)is among the worldwide key pests,damaging vegetables,fruit and ornamental trees,resulting in a huge amount of economic loss.Applying agrochemicals to control Tetranychus urticae has led to serious “3R” problem,environmental pollution,and food safety concern.Developing efficient and environmentally friendly preventive and control measures is urgently needed.Predatory mites of Phytoseiidae as a critical group of natural enemies in agriculture have received an increasing amount of attention.In this study,eight species of predatory mites were collected and identified,among which Neoseiulus pseudolongispinosus was found to have a great potential to control T.urticae.Laboratory populations of T.urticae and N.pseudolongispinosus were established.The group bisexual age-stage life table of T.urticae and N.pseudolongispinosus fed on T.urticae were constructed.The predation preference and the functional response of N.pseudolongispinosus fed on T.urticae eggs,larvae,and nymphs on four host plants were investigated.In addition,the cannibalism behavior of N.pseudolongispinosus on different host plants was explored.The results showed that N.pseudolongispinosus has a good control effect on T.urticae.The detailed results are as follows:Totally eight species in four genera from Phytoseiidae and one species of Blattisociidae were identified: Amblyseius tsugawai,Euseius utilis,E.ovalis,Euseius sp.,Neoseiulus californicus,N.pseudolongispinosus,Typhlodromus serrulatus(Phytoseiidae)and Blattisocius chondhrii(Blattisociidae).Laboratory populations of T.urticae and N.pseudolongispinosus were established under 25±1 ?,70±5% relative humidity and 16 L: 8 d photoperiod.The age-stage,two-sex life tables of T.urticae and that of N.pseudolongispinosus group-reared on T.urticae were constructed.The intrinsic rate of increase(r),finite rate of increase(?),net reproductive rate(R0),mean generation time(T)of T.urticae were 0.20±0.01 d-1,1.22±0.01 d-1,21.12±2.93 and 12.76±0.23 d,and these of N.pseudolongispinosus were 0.29±0.01 d-1,1.34±0.01 d-1,41.97±4.43,12.76±0.23 d,respectively.It implied that T.urticae as the prey was able to meet the needs of growth and development of N.pseudolongispinosus which can maintain a high survival rate and fecundity,i.e.a stable growth of the population.The predating preference of N.pseudolongispinosus on eggs,larvae and nymphs of T.urticae on four species of host plants including Capsicum annuum,Glycine max,Phaseolus vulgaris and Solanum melongena,were assessed.The results showed that the host plants did not affect the preference of N.pseudolongispinosus which preferred T.urticae eggs and larvae than nymphs.The predation efficiency of N.pseudolongispinosus on T.urticae was evaluated through investigating the functional response of the former to the latter on different host plants.The results showed a higher predation ability of N.pseudolongispinosus on T.urticae eggs and larvae than on nymphs on all the four host plants.The functional response of N.pseudolongispinosus on all the three developmental stage of T.urticae on Phaseolus vulgaris and Glycine max,and that of N.pseudolongispinosus on T.urticae eggs and nymphs fell in Holling II type model.The predation ability of N.pseudolongispinosus on Phaseolus vulgaris and Capsicum annuum was higher than that on Glycine max and Solanum melongena.Whilst,the searching ability of N.pseudolongispinosus to T.urticae was stronger on eggs and larvae than nymphsThe cannibalistic behavior of N.pseudolongispinosus female adults feeding on eggs,larvae,and nymphs of the same species were investigated on different plants.The results showed that the predation of N.pseudolongispinosus female adults varied greatly on different plants.The plant will affect the predatory efficiency of the female adult mite,among which,the predatory amount on Glycine max and Capsicum annuum was larger,and then was Phaseolus vulgaris bean and Solanum melongena.However,the survival time of N.pseudolongispinosus was not affected by plants.It implied that a cannibalism only took place in order to survive when the food was in short supply.In conclusion,N.pseudolongispinosus has a strong predation efficiency on T.urticae,and thus has the potential to be used as a biocontrol of T.urticae.