杏树次生代谢物质含量与小蠹虫危害的关系

为揭示杏树次生代谢物质含量与小蠹虫危害的关系,通过对小蠹虫不同危害程度的杏树树皮和树叶中的次生代谢物质(黄酮、单宁、总酚)质量分数进行研究,用方差分析和相关性分析判断各个次生代谢物质质量分数的变化与小蠹虫危害之间的关系。结果表明:不同危害程度的杏树,叶片中这3个次生代谢物质的质量分数间均无显著差异(P0.05);不同危害程度的杏树皮中黄酮和总酚质量分数之间存在显著差异(P0.05);不同危害程度的树皮中的单宁质量分数间无显著差异。经过相关性分析,受害程度与树皮中的次生代谢物质(黄酮、单宁、总酚)质量分数呈负相关性,总酚质量分数与受害程度的相关性最大,黄酮次之,单宁最小,其中与总酚在8月的相关性最大为(r=-0.878**),与单宁质量分数相关性在6月最小(r=-0.280)。     

蒲螨对多毛小蠹和光肩星天牛控制作用初探

研究了寄生性天敌蒲螨对多毛小蠹和光肩星天牛的控制作用。结果表明:在温度20±2℃、相对湿度50%±5%的室内环境下,蒲螨对多毛小蠹幼虫寄生效果较好,寄生率达100%。蒲螨对光肩星天牛幼虫不选择寄生。室外防治试验的结果表明,每厘米胸径释放蒲螨量20 000头和40 000头的多毛小蠹校正死亡率分别为58.86%和65.01%,寄生效果明显。     

新疆果树多毛小蠹生物学特性及防治

多毛小蠹是新疆果树重要害虫，危害杏树甚为严重。在库尔勒一年发生2～3代，主要以幼虫和少数成虫、卵在树皮内越冬，世代重叠。在自然变温下，卵历期4～11天，幼虫20～31天；蛹期6～9天；成虫10～35天。完成一世代需40～86天，主要以幼虫在寄主树表面活动。采用农业和药剂防治相结合效果显著。     

杏园脐腹小蠹空间分布型及易受害寄主生长性状研究

在脐腹小蠹(Scolytus schevyrewi Semenov)发生期,通过调查杏园脐腹小蠹空间分布及寄主生长性状发现:在杏园脐腹小蠹呈聚集分布,且个体间相互吸引,分布的基本成分是个体群;当种群密度1.68头/株时,环境条件是其聚集的主因;当种群密度4.92头/株时,脐腹小蠹的聚集习性和环境条件是脐腹小蠹聚集的主因;其为害程度与杏树新生枝条长度、直径、百叶重和叶片含水量呈显著负相关,与叶绿素含量无相关关系;不同受害程度杏树树脂分泌量呈正态分布,零星被害和持续被害杏树树脂分泌量显著大于健康和易被害致死杏树;6月平均新生枝条长度14.85cm、直径0.31cm、百叶重52.40g的杏树易受害,新生枝条长度12.70cm、直径0.29cm、百叶重49.36g的杏树易受害致死。     

基于MaxEnt模型预测欧洲榆小蠹的全球潜在地理分布

为探究欧洲榆小蠹Scolytus multistriatus在全球的潜在地理分布,根据其全球分布数据和筛选出的环境变量,利用MaxEnt模型预测其在当前气候及未来气候条件下的适生区。结果显示,所建MaxEnt模型的受试者工作特征曲线下面积（area under curve,AUC）大于0.9,表明模型预测结果可靠;利用刀切法对筛选出的环境变量进行分析后发现,12月平均最低温度对欧洲榆小蠹在全球的分布影响最大,同时也提供了最多的特有信息。在当前气候条件下,欧洲榆小蠹在全球的潜在分布范围主要集中在15° N~70° N和20° S~60° S之间,包括北美洲中部及南部、南美洲南部及东南沿海、欧洲、非洲中部、亚洲东部和大洋洲,适生区总面积约4.62×10⁷ km²。欧洲榆小蠹在我国的适生区广泛分布于20余个省（自治区、直辖市）,适生区总面积约为3.27×10⁶ km²。在未来气候条件下,欧洲榆小蠹的适生区面积将会扩大,并在SSP585（2081—2100年）情境下达到最大,为5.93×10⁷ km²。鉴于欧洲榆小蠹在我国具有较广的适生区,建议加强对其的检验检疫力度,防止其侵入我国。     

Evaluating Verticillium dahliae for biological control of Ophiostoma novo-ulmi in Ulmus minor

The ability of isolate Vd-48 of Verticillium dahliae to induce resistance against subsequent challenge with Ophiostoma novo-ulmi was examined in Ulmus minor . In the first experiment, conditioning inoculation of 5-year-old elm trees (2–3 m in height) with Vd-48 15 days prior to challenge inoculation with O. novo-ulmi significantly reduced wilting ( P  ≤ 0·05) compared with trees not conditioned with Vd-48. However, in another experiment on 6-year-old trees (2–3·5 m in height), no protection was achieved when the length of time between conditioning and challenge inoculations was 45 or 60 days. In a further experiment, inoculations with Vd-48 alone resulted in severe wilting in 22 out of 118 trees (6–10 years old and 4–7 m in height). Across the 2 years of this last trial, nine trees showed massive feeding wounds made by Scolytus sp., while O. novo-ulmi strains were isolated from six trees. Vd-48 provided a variable prophylactic effect against O. novo-ulmi in U. minor . Major difficulties with this approach to control Dutch elm disease are discussed.     

我国榆树死亡原因探讨——兼析是否发生荷兰榆病

60年代以来,新疆、内蒙、河南等地的白榆人工林和次生林陆续出现成群或成片死亡。1982-1985年,作者曾先后对其死亡情况进行了大量调查,并对病榆木质部变色条纹和危害榆树的小蠹虫做了分离培养和接种试验。从榆木枯萎症状,病菌形态及接种后无死亡现象的结果表明,均与世界流行的荷兰榆病无相似之处。初步认为齐腹小蠹是导致榆树死亡的直接原因,而干旱为小蠹虫的滋生创造了有利条件。     

果园脐腹小蠹伴生(共生)真菌群落组成及功能分析

【目的】研究新疆果树脐腹小蠹伴生真菌种类或类群,分析其功能,为脐腹小蠹为害机理和伴生真菌开发利用提供基础信息。【方法】在新疆疏勒、英吉沙等地采集被害果树上的脐腹小蠹成虫,利用MiSeq高通量测序技术和室内分离培养的方法,鉴定其伴生真菌种类或类群,通过FUNGuild功能预测和查阅相关文献,分析其功能。【结果】脐腹小蠹伴生真菌主要由7个门、24个纲、66个目、124个科的221个属组成;体表和肠道伴生真菌群落无显著性差异,体表伴生真菌优势菌群为Geosmithia、Saccharomycetales、Byssochlamys和 Wickerhamomyces,分别占群落的29.55%、19.50%、8.20%和6.07%;而肠道伴生真菌优势菌群为Geosmithia、Pleosporales和 Gibellulopsis,分别占42.14%,15.61%和6.97%;伴生真菌以腐生营养型、植物致病性、病理-腐生营养型和动物致病性为主,且不同果树脐腹小蠹均携带植物病致病性真菌,其中桃树脐腹小蠹携带植物致病型真菌比例最高,为19.06%;室内分离鉴定出伴生真菌13种,其中Geosmithia pallida、Yamadazyma mexicana和Cladosporium macrocarpum为植物病原菌,Wickerhamomyces silvicola、Meyerozyma guilliermondii、Rhodotorula mucilaginosa和Aureobasidium pullulans为多种植物病原菌的拮抗菌。【结论】新疆果树脐腹小蠹普遍携带、传播植物病原真菌,在防控脐腹小蠹的同时应注重果树枝干病害的防控,防止2类有害生物协同为害,加重危害;而伴生真菌中的有益拮抗菌可作为植物病害的生物防治菌被开发利用。     

榆树脐腹小蠹生物学习性初步研究

脐腹小蠹Scolytus schevy(?)i Seme. 是克拉玛依地区榆树的主要害虫,研究表明该虫在克市一年发生两代,以老熟幼虫越冬,雌虫产卵46—75粒。幼虫在韧皮部和木质部之问取食,造成植株输导组织破坏,营养及水分的运输受阻。林区气候干燥、郁闭度低、树势差,脐腹小蠹发生严重。室内涂干灭虫试验表明,40％久效磷,3％呋喃丹+柴油、六六六粉+柴油灭虫效果很好。     

Bark Beetle Demography in a Jeffrey Pine Stand as Influenced by Mechanized Thinning and Prescribed Fire

Forest thinnings implemented with cut-to-length and whole-tree harvesting systems followed by underburning were evaluated for their effects on bark beetle prevalence in pure, uneven-aged Jeffrey pine (Pinus jeffreyi Grev. & Balf.) interspersed with isolated California white fir (Abies concolor var. lowiana [Gord.] Lemm.). Based on pitch tube counts in a stand with a moderate bark beetle population in its pine component, the Jeffrey pine beetle (Dendroctonus jeffreyi Hopkins) generally preferred larger trees before treatment implementation, but after exhibiting mixed pretreatment tendencies concerning stand density demonstrated a posttreatment proclivity toward higher density. Cut-to-length thinning followed by underburning increased the pine beetle population while whole-tree thinning unaccompanied by burning reduced it. Tree mortality was induced by the bark beetle infestation but was not its sole cause. Pitch tube abundance on white fir far exceeded that on Jeffrey pine, and the greatest influence on the fir engraver (Scolytus ventralis LeConte) population was the prevalence of its host tree. The responses presented herein to these thinning and burning practices, which are being increasingly utilized in forest restoration efforts in the western USA, provide natural resource managers insight into potential forest health outcomes when implemented in Jeffrey pine and similar dry site forest types.