An evaluation of biological and abiotic controls for grapevine powdery mildew. 2. Vineyard trials

Grapevine powdery mildew ( Erysiphe necator) affects grape yield and fruit quality worldwide. Managers of conventional vineyards rely mainly on synthetic fungicides and sulfur to control powdery mildew, while in organic vineyards sulfur is the main control agent, often in rotation with canola-based oils, bicarbonates and biological control agents. The efficacy of those materials has not been evaluated critically under field conditions in Australia. Accordingly, a range of materials showing most promise in previous greenhouse trials (Crisp et al. 2006 Australian Journal of Grape and Wine Research 12 , pp. 192–202) were assessed via field trials in commercial vineyards. Applications of either milk or whey (alone, or mixed with a canola oil-based product), as well as applications of potassium bicarbonate (commercial formulation), all reduced the severity of powdery mildew compared with untreated vines. Eight applications of a 1:10 dilution of milk, 45 g/L whey powder or programs comprising rotations of potassium bicarbonate plus oil and whey, applied at 10–14 day intervals, reduced the severity of powdery mildew to levels not significantly different from that on vines sprayed with sulfur (wettable powder, 3–6 g/L). However, the relative control of powdery mildew by the test materials in field trials was dependent on the susceptibility of the grapevine cultivar and the extent of spray coverage achieved. In vineyards where highly susceptible cultivars were planted, and spray coverage was compromised, the resultant control of powdery mildew was reduced; and sometimes to commercially unacceptable levels.     

氟硅唑微乳剂的研制

对国内外文献未见报道的8％氟硅唑微乳剂制剂进行了研制，测定了其冷贮和热贮稳定性等理化性状及生物活性。对黄瓜自粉病室内毒力测定和田间药效试验结果表明，药效与40％乳油相当，对黄瓜安全。     

Molecular strategies to enhance the genetic resistance of grapevines to powdery mildew

The Eurasian winegrape Vitis vinifera has little or no genetic resistance to the major fungal pathogens, powdery mildew ( Erysiphe necator ) and downy mildew ( Plasmopora viticola ). These pathogens were first introduced into French vineyards from North America in the 1800s before spreading to all major grape producing regions of the world. As a result, grape production is highly dependent on the use of fungicides. With the increasing financial and environmental costs of chemical application and the emergence of fungicide-resistant strains, the introduction of natural genetic resistance against these fungal pathogens is a high priority for viticultural industries worldwide. We are utilising a number of different molecular approaches to increase our understanding of the basis of resistance to these important major fungal pathogens and to identify potential new sources of genetic resistance. This review will outline the progress and the potential of each of these different molecular strategies to the generation of fungal-resistant grapevine germplasm.     

Characterization of Erysiphe necator-Responsive Genes in Chinese Wild Vitis quinquangularis

Powdery mildew (PM), caused by fungus Erysiphe necator, is one of the most devastating diseases of grapevine. To better understand grapevine-PM interaction and provide candidate resources for grapevine breeding, a suppression subtractive hybridization (SSH) cDNA library was constructed from E. necator-infected leaves of a resistant Chinese wild Vitis quinquangularis clone “Shang-24”. A total of 492 high quality expressed sequence tags (ESTs) were obtained and assembled into 266 unigenes. Gene ontology (GO) analysis indicated that 188 unigenes could be assigned with at least one GO term in the biological process category, and 176 in the molecular function category. Sequence analysis showed that a large number of these genes were homologous to those involved in defense responses. Genes involved in metabolism, photosynthesis, transport and signal transduction were also enriched in the library. Expression analysis of 13 selected genes by qRT-PCR revealed that most were induced more quickly and intensely in the resistant material “Shang-24” than in the sensitive V. pseudoreticulata clone “Hunan-1” by E. necator infection. The ESTs reported here provide new clues to understand the disease-resistance mechanism in Chinese wild grapevine species and may enable us to investigate E. necator-responsive genes involved in PM resistance in grapevine germplasm.     

An evaluation of biological and abiotic controls for grapevine powdery mildew. 1. Greenhouse studies

Grapevine powdery mildew, caused by the fungus Erysiphe necator , is a major disease affecting grape yield and quality world-wide. In conventionally-managed vineyards, this disease is controlled mainly by regular application of sulfur and synthetic fungicides; and in organic agriculture, by sulfur and canola-based oils. Health and environmental impacts associated with the use of sulfur, development of resistance to certain synthetic fungicides, and demand for residue-free grapes, all point to a need for effective alternatives to sulfur and synthetic chemicals. Accordingly, seven greenhouse experiments were conducted to evaluate the potential of novel (abiotic) materials, as well as certain biological agents, for controlling powdery mildew. Application of Bacillus subtilis , milk (200 mL/L), whey (30 g/L), canola-based oils (2–4 mL/L) and Ecocarb (potassium bicarbonate, 3 g/L) all reduced the severity of powdery mildew, and in some cases by 96% compared with untreated controls. Such treatments thus offer potential as alternatives to sulfur in organic viticulture if their efficacy can be duplicated under field conditions – the subject of paper 2 in this series (Crisp et al. 2006, Australian Journal of Grape and Wine Research 12 , pp. 203–211).     

拮抗放线菌S-930-6发酵液精提物对几种作物病害的防治效果

用S-930—6发酵液精提物对小麦白粉病、西葫芦白粉病、黄瓜霜霉病进行了盆栽防效试验。试验结果表明，S-930—6精提物800mg／L对西葫芦白粉病的保护和治疗作用分别为91％和97％，对小麦白粉病的保护作用和治疗作用分别为83%，和59％，对黄瓜霜霉病的治疗和保护作用分别为84%和77％。     

百菌清含氟类似物对黄瓜白粉病的室内活性测定

比较了百菌清及其含氟类似物对黄瓜白粉病的室内防治药效。     

小麦与白粉病菌相互作用的钙调素定位

本文对白粉病菌侵染后小麦表皮细胞内钙调素的动态变化过程进行了分析。结果表明,在正常情况下钙调素主要集中分布在泡内和胞外,在细胞衰老时进入解体的细胞器如细胞核等;接种白粉病菌后,感病细胞内的钙调素含量降低;但随着细胞的衰老钙调素含量又逐渐增加。钙调素逐渐穿过吸器外膜进入吸器外基质和退化的吸器内部。病原菌侵染后,抗病细胞中的钙调素迅速增加,并随着细胞的死亡散布在这个细胞中,上述结果说明,适当的钙离子浓度梯度是白粉病菌吸器发育和行使其功能的重要条件。     

大豆与白粉病菌相互作用的超微结构与细胞化学

对大豆与白粉病菌相互作用的超微结构与细胞化学的研究表明,病原菌随着胞的侵染可诱导绝大多数寄主细胞产生强烈的乳突反应,但缺乏有效的乳突抗性。抗病寄主的细胞以过敏性反应抑制病原菌的侵染,病菌初生吸器的产生往往诱导感病寄主的细胞代谢迅速增强,甚至分化成一些结构简单但却能够进行光合作用的小型叶绿体。与菌丝相比,病菌分化孢子和吸器的壁中只含有少量的几丁质,而吸器外围的分枝几乎没有。