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Hu Y.,Beijing Forestry University | Tian C.-M.,Beijing Forestry University | Cairangdanzhou,Forest Pest Control and Quarantine Station of Qinghai Province | Li Z.-Y.,Beijing Forestry University | And 3 more authors.
Beijing Linye Daxue Xuebao/Journal of Beijing Forestry University | Year: 2014

Our research focused on Arceuthobium sichuanense and its host in Xianmi forest region, Qinghai of northwestern China, and transect survey method was chosen to investigate the typical sub-compartment. By analyzing the disease incidence, it was found that the hazard of A. sichuanense in the sub-compartment gradually increased from foot to the top of hill. Then all crown-third DMR (dwarf mistletoe rating) distribution of the host was counted in transect, it was figured out that A. sichuanense preferred to distribute from lower to the upper crown of the host. Forty standard samples were set in Xianmi forest region, taking DMI (dwarf mistletoe idex), mean DBH, mean height, stand type, mingle index, herb cover, moss depth as response variables, taking canopy density, slope, elevation as environmental factors. It was ascertained that crown density, slope, slope position, elevation and stand type were main factors which had an effect on the outbreak of A. sichuanense by using RDA analysis, in which the canopy density had a significantly negative correlation with the incidence of dwarf mistletoe; the slope and elevation had a significantly positive correlation with the incidence of dwarf mistletoe; the stand composition had an effect on the occurrence of dwarf mistletoe, and the dwarf mistletoe was less harmful in the higher mingling forest. Source

Zhang C.,Beijing Forestry University | Chen L.,Beijing Forestry University | Tian C.-M.,Beijing Forestry University | Li T.,Xianmi Forest Farm | And 2 more authors.
Beijing Linye Daxue Xuebao/Journal of Beijing Forestry University | Year: 2016

Sichuan dwarf mistletoe (Arceuthobium sichuanense) is a plant that parasitizes Picea trees. Recently, this dwarf mistletoe has caused serious damage to spruce trees in Sanjiangyuan area, Qinghai Province. In this study, based on the data on the reported sites, we applied GARP and MaxEnt niche models to predict and analyze the distribution area of A. sichuanense in China. The predicted results were then tested by ROC curves. The results showed that the predicted area by GARP model was more extensive while the area by MaxEnt model was more detailed. Thus, GARP and MaxEnt models were combined with a weight ratio 4:1 to predict the distribution area of A. sichuanense. The AUC value of GARP-MaxEnt model was 0.937, indicating that the precision of prediction was high. Based on the GARP-MaxEnt prediction model, it is shown that the distribution area of A. sichuanense is mainly in Qinghai, Gansu, Sichuan and Tibet. The junction area of Qinghai, Gansu and Sichuan was the most suitable area for A. sichuanense parasitism. The results will benefit our understanding of the distribution area of A. sichuanense, and have an guiding significance for monitoring the disease and making scientific strategy to control this dwarf mistletoe. © 2016, Beijing Forestry University. All right reserved. Source

Xia B.,Beijing Forestry University | Xia B.,ShenYang Agricultural University | Tian C.-M.,Beijing Forestry University | Luo Y.-Q.,Beijing Forestry University | And 4 more authors.
Forest Pathology | Year: 2012

Arceuthobium sichuanense is a hemiparasitic angiosperm that infects Qinghai spruce (Picea crassifolia Kom.) in Qinghai province, China, and causes severe damage to spruce forests in Qinghai-Tibet Plateau. In this study, the impact of A. sichuanense infection on mature and young trees of Qinghai spruce was evaluated by examining needle and current-year shoot morphology, needle water and nitrogen-use efficiency (NUE) and needle nitrogen concentration. The most apparent effect of A. sichuanense infection was a significant reduction in both needle size distal to infection and current-year shoot length in the infected branches (p<0.001). Per cent reductions in needle and current-year shoot length were similar between mature and young trees (58.9 vs. 56.3%; 59.7 vs. 62.9%). There was a high degree of correlation in foliar δ 15N values between the dwarf mistletoe and its host trees (R 2=0.9017, p<0.001), while the foliar δ 13C values of A. sichuanense were similar to those of infected mature and young spruce trees. The dwarf mistletoe infection also resulted in a significant decrease in host needle N concentration and δ 13C values (p<0.001). The per cent reduction in needle N concentration in young trees was nearly twice as much as that in mature trees (20.49 vs. 11.54%), while the per cent reduction in needle δ 13C values was similar between young and mature trees (-0.98 vs.-1.1‰). The NUE in mature trees was not affected by A. sichuanense infection, but the NUE in young trees was increased by the infection. © 2012 Blackwell Verlag GmbH. Source

Zhang Q.-H.,Sterling International Inc. | Ma J.-H.,Forest Pest Control and Quarantine Station of Qinghai Province | Yang Q.-Q.,Forest Pest Control and Quarantine Station of Qinghai Province | Byers J.A.,U.S. Department of Agriculture | And 3 more authors.
Pest Management Science | Year: 2011

BACKGROUND: Monitoring traps and control methods are needed for the long-legged chafer, Hoplia spectabilis Medvedev, which has recently reached outbreak numbers in pastureland of Qinghai Province, China.RESULTS: Field trapping experiments, using cross-pane funnel (barrier) traps, showed that H. spectabilis adults were not significantly attracted to branches of the host plant Dasiphora fructicosa (L.) Rydb. However, beetles were slightly attracted to similar host plant branches infested by conspecific beetles, possibly owing to weakly attractive volatiles, primarily (Z)-3-hexenyl acetate, released from beetle-damaged host leaves. This compound was weakly attractive when released from traps. However, H. spectabilis beetles showed strong visual responses to yellow- or white-painted trap panes, with weaker responses to blue, red or green panes, and least response to black panes. Black traps at 0.2-1.5 m above ground intercepted significantly more beetles than traps at 2.5 m. The mean flight height based on trap catches was 0.88 m (SD = 0.76), yielding an effective flight layer of 1.9 m. Flight response of beetles to colored barrier traps occurred between 10:00 and 18:00, and peaked between 12:00-14:00, when daily temperatures reached their maximum.CONCLUSION: Unbaited yellow or white cross-pane funnel traps are recommended for both monitoring and mass-trapping programs against this economically and ecologically important scarab beetle. © 2010 Society of Chemical Industry Copyright © 2010 Society of Chemical Industry. Source

Zhang Q.-H.,Sterling International Inc. | Ma J.-H.,Forest Pest Control and Quarantine Station of Qinghai Province | Zhao F.-Y.,Forest Pest Control and Quarantine Station of Qinghai Province | Song L.-W.,Jilin Provincial Academy of Forestry science | And 2 more authors.
Agricultural and Forest Entomology | Year: 2011

1Volatiles from the hindgut extracts of males of the Oriental spruce engraver Pseudips orientalis (Wood & Yin) (Coleoptera: Curculionidae, Scolytinae) of different phases of gallery development were analyzed by gas chromatography-mass spectrometry-flame ionization detection (GC-MS/FID) with both polar and enantioselective columns.2GC-MS/FID analyses showed that unmated males or males mated with one female produced approximately 95%-(-)-ipsenol and (-)-cis-verbenol as major components, as well as (-)-trans-verbenol, myrtenol, approximately 70%-(+)-ipsdienol and (-)-verbenone as minor or trace components. The release of these male-produced compounds was confirmed by GC analysis of an aeration sample of a P. orientalis-infested spruce log. Mating reduced production of the male-specific hindgut volatiles.3A field-trapping bioassay in Qinghai, China, showed that a ternary blend containing two major components, 97%-(-)-ipsenol (i.e. close to naturally produced enantiomeric ratio) and (-)-cis-verbenol, plus a minor component (-)-trans-verbenol, caught significantly more P. orientalis beetles (♂: ♀ = 1: 2.7) compared with the unbaited control. Subtraction of (-)-trans-verbenol from the active ternary blend had no significant effect on trap catches. The addition of (±)-ipsdienol (at 0.2 mg/day release) to the active ternary or binary blends significantly interrupted their trap catches. Replacing 97%-(-)-ipsenol with (±)-ipsenol in the ternary blend significantly reduced trap catches to a level that was no different from the blank control.4 Pseudips species were sister to all other Ipini genera in a phylogeny reconstructed with mitochondrial cytochrome oxidase I DNA data for 51 Ipini and outgroup species.5The results obtained suggest that the two major components, 95%-(-)-ipsenol and (-)-cis-verbenol (at approximately 4-5 1), produced by unmated fed males, are probably the primary aggregation pheromone components for P. orientalis. In light of the phylogeny, the use of terpenoid semiochemicals as pheromones probably occurred early in the evolution of Ipini and these semiochemical blends were subsequently modified in the process of speciation. © 2010 The Authors. Agricultural and Forest Entomology © 2010 The Royal Entomological Society. Source

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