The affect of pest insects and diseases to natural seabuckthorn shrinkage in Zavkhan river basin, Mongolia
B Munkhtsetseg, A Uranchimeg, D Ganbat, D Jagdag
The wild seabuckthorn, hippophae which is counted in the subspecies of H.rhamnoides L.ssp.mongolica Rousiin Mongolia is popular in western part of the country in Bulgan, Khovd, Zavkhan, Tes, Bukhmurun and other small rivers in Selenge river basin. The initial research result stating the wild sea buckthorn was widespread in around 30000 hectare area in the country. Very recently it has been reassessed that the area of bushes of seabuckthorn covers around 14358.5 hectare in 2019. These studies show the wild sea buckthorn bushes have been decreased by more than 50 percent due to harsh weather conditions and misuse of human beings.Early June study shows that 80 percent of seabuckthorn groves at research field was dying or getting old, 20 percent of the remaining live bushes was male and had only 20-30 percent of its spires survivable. The number of died and dried bushes in 10m2ground was 83 in average. 60-70 percent of the dried and died bushes had its dried and blackened fruits remained. At the first ten days of September, bushes had defects mostly leaves becoming torn, growth of tree excrescence in 60 percent and 30-100 percent of leaves were torn of a bush at grove in Khar But. At the same time, the defects were less at Ulaan buraa, 20 percent of bunches were damaged and leaves of a bush were torn by 10-40 percent. The research fields were affected by a fruit fly, Rhagoletis batava(Hering 1958) of Tephritidae family. The sea buckthorn grove in Khar But had 30 percent of bushes dried that caused of plant diseases and 50 percent of its bushes were drying. When the died and dried branches were examined, they were diagnosed as affected Aspergillus spp, Penicillium spp, Fusarium sporotrichioidesand gray mold. Also the rot in the main tube had fungus of Fusarium spp.group. These results demonstrate the drying of bushes are caused by the diseases moldered by the Fusarium wilt.As there has not been any study on the diseases of wild seabuckthorn grown along Zavkhan river and no actions taken to control the diseases and insects. The shrinkage of bushes is expanding intensely caused by damages combined of fruit shrinkage, leaf torn, change of shape, main phylum rotting, damage by fruit fly worm and diseases like Fusarium sporotrichiella.