绿色木霉菌剂对花生重茬病害的防治效果研究

对不同连作年限的重茬花生的根部病害发生情况进行了调查,鉴定了引起花生重茬病害的主要病原真菌。结果表明花生重茬病主要是由于引起花生根腐病的镰刀菌属和引起花生立枯病的丝核菌属真菌在土壤中数量增加所至。T42木霉对两种重茬病菌的平板拮抗实验结果表明,T42木霉对两种病菌具有明显的拮抗作用,其竞争机制包括营养、空间的竞争以及抗生作用。以该木霉发酵产物制成生物农药施入田间能够明显控制花生重茬病害的发生。     

木霉菌对杀菌剂的耐药性

以前关于木霉菌的研究主要集中在其生物防治作用方面,对于木霉菌作为有害菌时如何选择杀菌剂进行化学防治以及木霉菌作为生防菌时如何协调生物防治和化学防治,这些问题研究得很少。为提高对病害的综合防治效果,本实验就三种常用于防治番茄灰霉病的杀菌剂,对五种木霉菌株的抑制能力进行了室内测定。     

拮抗微生物对枣果实采后病害生物防治的研究进展

枣果实采后极易发生真菌侵染性病害而造成重大损失,利用拮抗微生物防治枣果实采后病害是替代化学合成杀菌剂的一种绿色、环保、安全的防治方法.目前应用于防治枣果实采后病害的拮抗微生物主要为梅奇酵母属(Metschnikowia sp.)、假丝酵母属(Candida sp.)、隐球酵母属(Cryptococcus sp.)以及芽...     

Biocontrol ability and action mechanisms of Aureobasidium pullulans GE17 and Meyerozyma guilliermondii KL3 against Penicillium digitatum DSM2750 and Penicillium expansum DSM62841 causing postharvest diseases

Epiphytic yeasts were isolated from different cultivars of apples and lemons and identified by a combination of PCR-RFLP of 5.8S rRNA region and sequencing of D1/D2 domain of the 26S rRNA gene. Among 69 isolates, Aureobasidium pullulans GE17 and Meyerozyma guilliermondii KL3 strains showed the greatest antagonistic activity against two significant apple and lemon postharvest pathogens, Penicillium expansum DSM62841 (blue mold) and Penicillium digitatum DSM2750 (green mold), after preliminary screening. Yeasts were applied as single and mixed cultures with two different cell concentrations of 10⁶ and 10⁸ cells/ml in the present study. It was determined that antagonistic activity of two yeast strains studied emerged with a combination of several mechanisms of action including competition for space and nutrients, production of volatile organic compounds (VOCs), secretion of extracellular lytic enzymes and inhibition of fungal spore germination. The highest inhibition of mycelial growth on P. expansum DSM62841 and P. digitatum DSM2750 (83.4% and 74.7%, respectively) was achieved by utilization of single culture of A. pullulans GE17. Otherwise, the application of mixed culture at the ratio of 10⁸ cells/ml inhibited spore germination of both pathogens from 86% to 95%. Results of this study suggest that an increase in yeast cell concentrations positively affected their biocontrol activity against blue and green molds. According to the results, employing single culture of M. guilliermondii KL3 did not exhibit effective antagonistic activity against blue and green molds. However, utilization of A. pullulans GE17 alone and mixed culture showed succesfull controlling against both P. expansum DSM62841 and P. digitatum DSM2750.     

裸脚菇0612-9活性物质对柑橘青、绿霉病的生防效果及其诱导抗性

为研究裸脚菇0612-9活性物质对柑橘青、绿霉病的生防效果及其诱导抗性，以‘南丰’蜜桔为试材，采用质量浓度分别为0（对照）、0.25、0.55、5.50 mg/mL的裸脚菇0612-9发酵液粗提物（extract of fermentation broth from Gymnopus sp. 0612-9，GSFE）通过损伤接种的方式处理果实，随后分别接种青、绿霉病原菌孢子悬浮液，定期统计果实发病率，并取样测定柑橘果皮防御酶活力等指标的变化。结果表明：不同质量浓度GSFE处理较对照组均能显著降低柑橘青、绿霉病发病率及病情指数（P＜0.05），其中GSFE质量浓度为5.50 mg/mL时的抑制效果最佳；同时，GSFE处理能够诱导‘南丰’蜜桔果皮中相关防御酶（苯丙氨酸解氨酶、超氧化物歧化酶、过氧化物酶）活力的提高，促进其抗氧化物质总酚和类黄酮的产生，并抑制脂氧合酶活力、减少丙二醛的积累、降低膜脂过氧化程度，从而提高‘南丰’蜜桔果实的抗病性。本研究结果可为设计开发GSFE类新型柑橘采后防腐保鲜剂提供思路。     

不同生物防治菌株对番茄灰霉病防治效果的影响

采用室内筛选的11个生物防治菌株进行盆栽和田间小区防治番茄灰霉病试验结果表明，细菌B27，真菌F45和F120，放线菌A15和A111，具有较好的预防效果，防治效果均在60％以上，其中放线菌A15菌株，防治效果达70％以上。菌株组合真菌F20＋F45和F20＋F120，F45＋F120和细菌B24＋B28具有增效作用。其中F45＋F120和B28＋B24组合．防治效果分别为69．2％和70.2％。     

Solid substrate bioassay to evaluate impact of Trichoderma on trichothecene mycotoxin production by Fusarium species

BACKGROUND: Fusarium head blight of wheat is a destructive disease in various wheat‐growing regions and leads to significant yield losses for farmers and to contamination of cereal grains with mycotoxins, mainly deoxynivalenol and its derivatives. Toxigenic Fusarium species sporulate on cereal crop residues and produce significant inoculum for epidemics. Reduction of mycotoxin production and pathogen sporulation may be influenced by saprophytic fungal antagonists. RESULTS: Trichoderma isolates were examined in dual culture bioassays on rice with two isolates of Fusarium graminearum Schwabe and two isolates of Fusarium culmorum (W.G. Smith) Saccardo, belonging to three different chemotypes. Production of five trichothecene mycotoxins, deoxynivalenol (DON), 3‐acetyl‐deoxynivalenol (3AcDON), 15‐acetyl‐deoxynivalenol (15AcDON), nivalenol (NIV) and fusarenone X (FUS), was reduced by over 95%. Two Trichoderma isolates partially reduced the amounts of four metabolites when inoculated on autoclaved cultures of the same four Fusarium isolates. However, in the case of the 15AcDON chemotype of F. culmorum culture the content of DON increased and that of 15AcDON decreased. Isolates of Trichoderma varied in their ability to inhibit production of the five trichothecene mycotoxins by Fusarium. Susceptibility of the four Fusarium isolates to antagonistic activity of the same Trichoderma isolate differed significantly. CONCLUSION: Selected non‐toxigenic Trichoderma isolates proved to be useful biocontrol agents against toxigenic Fusarium pathogens of wheat, significantly reducing production of the trichothecene mycotoxins DON, NIV and their acetylated derivatives. Copyright © 2007 Society of Chemical Industry     

黄瓜苗病拮抗菌的筛选与活性测定

试验筛选出具有生物防治作用的3株细菌B2、B3、B9和1株真菌FT3（水霉菌）。它们对由立枯丝核菌（Rhizoctoniasolani)和瓜果腐霉菌（Pythium aphanidermatum)引起的苗病有较明显的防治效果，其中B9和FT3对由瓜果腐霉菌引起的苗病防治效果高达70％以上。B9和FT3在病菌接种量不高的条件下混合使用可表现出协同防病作用。化学农药福美双对生防细菌B9的防病功能有促进作用，但却抑制木霉菌的生物防治效果。