The research result were showed: Most Cryptotympana atrata(Fabricius) nympha had out of soil molting at the leaf back.The egg grain was basically to come together in one branch segment of spawning egg,the length variation was greater and the diameter variation was smaller about a branch segment of spawning egg of the fragrant pomelo.The density and the coefficient of variation was big in the pomelo orchard at the mound low hill loins.The distribution type of Cryptotympana atrata(Fabricius) adult and branch of spawning egg belong to the core distribution in the pomelo orchard,that was caused by the kind gathering or common function of it with the environment variation.Their basic section were individual group,the individual group gathering distribution presents straight line increment along with the kinds' density exaltation,and incline toward gradually a random distribution.Sampling investigation in the pomelo orchard,sampling 10～30 plants when Cryptotympana atrata(Fabricius) average density5per plant,sampling 5～10 plants when Cryptotympana atrata(Fbaricius) average density5per plant.

The outbreak reasons of the pomelo citrus melaruse were analysed by system invertigation,sampling investigation,visiting,test,application and so on.The results showed that the main reasons were followed:(1)unsuitable planting management resulted in that a great deal of germina chronically accumulated and the resistance of pomelo trees reduced;(2)black cicada etc.caused a lot of wounds and deadwood;(3)there was no enough attention when plant disease happened;(4)there was suitable microclimate for the pomelo citrus melanose in pomelo park.Integrated control managements including focusing on scientific orchard construction,standardized planting,black cicada control in resarce pattern,proper application of pesticide,and protecting fruits with covers could effectively control damages caused by pomelo citrus in the moderate outbreak year.