Study On The Habitat Plants,breeding And Application Of Euseius Nicholsi In Gannan

Euseius nicholsi(Ehara et Lee)is a local predatory mite in Gannan,which plays a positive role in the prevention and control of pest mites,so that the number of pest mites in the natural ecosystem has been kept under the controlling threshold for a long time.To maximize its effect of prevention and controlling of E.nicholsi on pest mites in navel orange orchard in Gannan and from the perspective of the applicative research including the survey of local fitness,the selection of artificial diet and the evaluation of predation ability,we use the populations of E.nicholsi in Gannan as the research object,investigating its habitat plants range and the wintering situation in Gannan,studing the effects of feeding the pollen of Luffa cylindrica,Tetranychus cinnabarinus and the mixture of the pollen of L.cylindrica with T.cinnabarinus on the reproductive development and growth of E.nicholsi,and the predacious function of E.nicholsi(larve,nymph and adult)to each stage of P.citri.The main results are as follows:1.E.nicholsi has widely habitat plants range in Gannan area.In this investigation,we found the populations of E.nicholsi in some herbs,shrubs and small trees.These habitat plants involve the Rosaceae,Lauraceae,Theaceae,leguminosae,Pittosporaceae and other 13 families,including Camellia japonica,Cercis chinensis,Pittosporum tobira,Sida rhombifolia,Kalimeris indica,Michelia alba,Michelia chapensis,Ligustrum sinense,Rosa multiflora Thunb.var.cathayensis Rehd.,amounting to 17 kinds of plants.In addition,the over-wintering places of E.nicholsi in Gannan include the hollow of abaxial leaf surface near the center vein,the fallen leaves,or anywhere else.The most over-wintering stage of E.nicholsi was the female adult in diapause.When the weather gets warmer,the over-wintering female adult start laying eggs and then pass into death,but the populations of E.nicholsi started to pick up.2.The study is under the conditions(Temperature 25 ?,Relative Humidity 75 ± 5%,Photoperiod 10L:14D)in artificial climate chamber.The result indicated that when they were feeded with the pollen of L.cylindrica,T.cinnabarinus,or the mixture of the pollen of L.cylindrica with T.cinnabarinus,the development durations of E.nicholsi is 4.48 d,6.01 d and 5.61 d,respectively.The life-span of E.nicholsi feeded with these foods was L.cylindrica > L.cylindrica pollen + T.cinnabarinus >T.cinnabarinus,and the life-span of female mites all longer than males.When they were feeded with the pollen of L.cylindrica,the oviposition during of E.nicholsi is shortest,but the diurnal and total amount of oviposition is largest.Under these food conditions,the experimental populations all goes up,and the population tendency index is largest when they were feeded with the pollen of L.cylindrica.Meanwhile,when they were feeded with the pollen of L.cylindrica,its parameters of population dynamics,such as Net reproductive,Instant increment rate and Population doubling time,was more outstanding than other foods.The double population time of E.nicholsi feeded with E.nicholsi was 3.47 d.When they were feeded with L.cylindrica pollen + T.cinnabarinus or T.cinnabarinus,it was 4.62 d or 7.7 d,respectively.The results show that breeding effectiveness of the mixture food of L.cylindrica pollen with T.cinnabarinus close to the pollen of L.cylindrica.3.E.nicholsi(larve,nymph and adult)all has a strong predation ability to each stage of Panonchus citri.Among them,the female adults of E.nicholsi have the largest average daily predation to P.citri.Under different densities of prey,the function responses of E.nicholsi(larve,nymph and adult)to each stage of P.citri were accord with Holling II disc equation,and the preying effectiveness of the female adults of E.nicholsi to the larva of P.citri was largest,up to 25.2865.In addition,the female adult of E.nicholsi to each stage of P.citri has obvious interference response.With the densities of the female adult goes up,the total amount of predation of E.nicholsi increase,but the average amount of predation of E.nicholsi decrease.In complex prey environment,the predator has certain selectivity when hunts prey.The study found that the selection coefficients of the female adults of E.nicholsi to the larve and nymph of P.citri has higher,when the eggs,larvae,nymphs and adults of P.citri exist at the same time.