The occurrence regularity of psyllid in Haloxylon spp and its influencing factors
梭梭木虱发生规律及其影响因子

The leafy-bracted galls were observed in the Haloxylon ammodendron and H. persicum in the Gurbantunggut Desert of Xinjiang. Its incidence rate was above 90% which was caused by four species of psyllids: Caillardia robusta, C. azurea, C. nana and C. notata respectively, and the latter two species were newly recorded from China. There were two incidence peaks of Haloxylon spp every year, respectively in the mid-May and mid-June in H. ammodendron and in mid-May and late July to early August in H. persicum. The occurrence amount of psyllids in H. ammodendron was the most serious at interdune and there was no much significance between dunes edges and gravel desert; The occurrence amount of psyllids in H. persicum was more serious at low dunes than that at high dunes, and sunny slope than shady slope. Incidence rate of the galls increased along with the tree-ages. Topography, tree vigour, direction and topography*slope have significant influences on the occurrence of psyllids, but their interactions have no apparent effects on the galls. The occurrence regularity of psyllids in H.ammodendron and H.persicum and psyllids' relations with surrounding environment in the Gurbantunggut Desert were studied in this paper, which provide a basis for protecting desert ecological environments.