Identification of banana fusarium wilt using supervised classification algorithms with UAV-based multi-spectral imagery

The disease of banana Fusarium wilt currently threatens banana production areas all over the world.Rapid and large-area monitoring of Fusarium wilt disease is very important for the disease treatment and crop planting adjustments.The objective of this study was to evaluate the performance of supervised classification algorithms such as support vector machine(SVM),random forest(RF),and artificial neural network(ANN)algorithms to identify locations that were infested or not infested with Fusarium wilt.An unmanned aerial vehicle(UAV)equipped with a five-band multi-spectral sensor(blue,green,red,red-edge and near-infrared bands)was used to capture the multi-spectral imagery.A total of 139 ground sample-sites were surveyed to assess the occurrence of banana Fusarium wilt.The results showed that the SVM,RF,and ANN algorithms exhibited good performance for identifying and mapping banana Fusarium wilt disease in UAV-based multi-spectral imagery.The overall accuracies of the SVM,RF,and ANN were 91.4%,90.0%,and 91.1%,respectively for the pixel-based approach.The RF algorithm required significantly less training time than the SVM and ANN algorithms.The maps generated by the SVM,RF,and ANN algorithms showed the areas of occurrence of Fusarium wilt disease were in the range of 5.21-5.75 hm2,accounting for 36.3%-40.1%of the total planting area of bananas in the study area.The results also showed that the inclusion of the red-edge band resulted in an increase in the overall accuracy of 2.9%-3.0%.A simulation of the resolutions of satellite-based imagery(i.e.,0.5 m,1 m,2 m,and 5 m resolutions)showed that imagery with a spatial resolution higher than 2 m resulted in good identification accuracy of Fusarium wilt.The results of this study demonstrate that the RF classifier is well suited for the identification and mapping of banana Fusarium wilt disease from UAV-based remote sensing imagery.The results provide guidance for disease treatment and crop planting adjustments.

Banana Fusarium Wilt(Fusarium oxysporum f. sp. cubense)Control and Resistance, in the Context of Developing Wilt-resistant Bananas Within Sustainable Production Systems

Banana(Musa spp.) is seriously threatened by the soil-borne fungus Fusarium oxysporum f. sp. cubense(Foc), also known as Panama disease.Attempts to control Fusarium wilt with fungicides damage soil health and have limited efficiency due to pathogenic variability. Elucidating the mechanism of infection and molecular basis of host defense through banana genome sequencing, genome editing and proteomic profile analysis will help formulate strategies to develop resistant cultivars. This will include research to better understand the functions of Fusarium wilt-resistance proteins. Transgenic approaches and protoplast fusion could be employed as tools for transferring resistance genes from wild relatives to commercial banana varieties, and may serve as a new strategy in solving the problems faced by banana breeding programmes.Evaluation of banana germplasm for resistance to Fusarium wilt using in vitro mutation and selection, along with somaclonal variation and somatic hybridization, could improve banana breeding efficiency for resistance against Foc. Plant hormones could also play an important role in regulating plant growth and defense by mediating developmental processes and signaling networks involved in banana responses to Foc. A complementary approach for managing Fusarium wilt, such as exclusion, surveillance and biological control as important components of integrated disease management programs must be considered to prevent and contain contagion. This includes studies on banana plant-microbe interactions, embracing both plant growth promoting rhizobacteria(PGPR) to induce Foc resistance, and exploring Foc-derived elicitors for inducing defense-related enzymes in bananas. The role of Silicon and crop and livestock integration must also be included in the Fusarium control toolbox. The current review also gathers knowledge of the biotechnological approaches along with biological control of Fusarium wilt of banana that will provide researchers insights and criteria to develop future studies.

Induction of Tolerance to Fusarium Wilt and Defense-Related Mechanisms in the Plantlets of Susceptible Berangan Banana Pre-Inoculated with Pseudomonas sp.(UPMP3) and Burkholderia sp.(UPMB3)

This study is aimed at assessing the ability of two endophytic bacteria originally isolated from healthy oil palm roots, Pseudomonas sp. （UPMP3） and Burkholderia sp. （UPMB3） to induce resistance in susceptible Berangan banana against Fusarium oxysporum race 4 （FocR4）. Increased accumulation of resistance-related enzymes such as peroxidase （PO）, phenylalanine ammonia lyase （PAL）, lignithioglycolic acid （LTGA）, and pathogenesis-related （PR） proteins （ehitinase and β-1,3-glucanase） has been observed in plantlets treated with endophytic bacteria UPMP3 and UPMB3 singly or as mixture under glasshouse conditions. Pre-inoculation of banana plantlets with UPMP3 showed a significant reduction in Fusarium wilt incidence 72 d after challenged inoculation with FocR4. UPMB3 was less effective in suppressing Fusarium wilt compared to UPMP3, whereas, the mixture of both endophytes showed an intermediate effect. Based on these results, it is concluded that UPMP3 could be a promising biological control agent that can trigger resistance against Fusarium wilt in susceptible Berangan banana.

DNA methylation patterns of banana leaves in response to Fusarium oxysporum f. sp. cubense tropical race 4

Fusarium wilt of banana, which is caused by Fusarium oxysporum f. sp. cubense tropical race 4 （Foc TR4）, is a serious soil-borne fungal disease. Now, the epigenetic molecular pathogenic basis is elusive. In this study, with methylation-sensitive amplification polymorphism （MSAP） technique, DNA methylation was compared between the leaves inoculated with Foc TR4 and the mock-inoculated leaves at different pathogenic stages. With 25 pairs of primers, 1 144 and 1 255 fragments were amplified from the infected and mock-inoculated leaves, respectively. DNA methylation was both changed and the average methylated CCGG sequences were 34.81 and 29.26% for the infected and the mock-inoculated leaves. And DNA hypermethylation and hypomethylation were induced by pathogen infection during all pathogenic stages. Further, 69 polymorphic fragments were sequenced and 29 of them showed sequence similarity to genes with known functions. And RT-PCR results of four genes indicated that their expression patterns were consistent with their methylation patterns. Our results suggest that DNA methylation plays important roles in pathogenic response to Foc TR4 for banana.

Suspensions Derived from Anaerobically Fermented Tilapia Offal Inhibit <i>Fusarium oxysporum</i>f. sp. <i>cubense</i>in Banana

Effective control strategies are lacking for Fusarium wilt of banana crops worldwide. Here, the inhibitory efficacy of suspensions derived from Tilapia offal by anaerobic fermentation against Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4) was evaluated. Two anaerobic fermentation methods were used: 1) natural fermentation of offal (NF) and 2) fermentation of offal supplemented with 5% lime (LF). The suspensions were applied in three treatments: Plate assay, pot system, and in the field. The inhibition rate and disease index were determined. The results showed that the inhibition was significantly greater for LF than for NF on plates. In pot system and in the field, the disease index was lower for the LF group than for the NF group and was significantly lower than that of the control. Therefore, suspensions derived from anaerobically fermented offal provide a new control method for Fusarium wilt in banana.

Construction of PEG-mediated Genetic Transformation and Gene Knockout System in Fusarium oxysporum f. sp.cubense Tropic Race 4

Fusarium wilt of banana, caused by Fusarium oxysporum f. sp. cubense tropic race 4(Foc TR4), is a typical vascular and soil-borne disease which has significantly threatened the sustainable development of banana industry. In order to reveal the infection process and pathogenesis of Foc TR4, the young mycelia(66.7 mg/ml) of wild-type strain of Foc TR4(WT-Foc TR4) cultured for 18-20 h were lysed with enzyme mixture for protoplast formation, which consisted of 25 mg/ml driselase, 0.4 mg/ml chitinase, 15 mg/ml lysing enzyme and 1.2 mol/L potassium chloride. The resulted protoplasts of 2×10~7 cells/ml were used to test the efficiency of transformation mediated by polyethylene glycol, and up to 9 transformants per microgram of DNA were obtained. AmCyan, RFP and YFP genes were stably transferred into the WT-Foc TR4, separately, using the protoplast transformation system. The gene FoOCH1 encoding α-1, 6-mannosyltransferase in the WT-Foc TR4 was knocked out using the split-marker recombination technology. The genetic transformation and gene knockout system in this pathogen lays a foundation for the study of functional genomics and plant-pathogen interactions.

香蕉枯萎病高效拮抗土著细菌的筛选及其防效

【目的】发掘防治香蕉枯萎病的高效生防菌资源,为有效控制香蕉枯萎病的发生提供参考。【方法】利用选择性培养基从福建省香蕉产区野生香蕉根际土壤中分离菌株,以香蕉枯萎病菌为靶标,采用平板对峙法、代谢物抑菌试验、抑菌谱和耐毒素能力测定筛选具有拮抗活性的生防细菌;通过形态学观察、生理生化特性测定、16S rDNA和gyrA基因序列分析及构建系统发育树进行生防菌株的鉴定,并采用灌根法测定生防菌株对香蕉枯萎病的防治效果。【结果】利用选择性培养基从野生香蕉根际土壤中分离到195株细菌,以香蕉枯萎病菌为靶标,采用平板对峙法筛选出对香蕉枯萎病菌具有拮抗活性的细菌17株,其中菌株NJ-1和NJ-4对香蕉枯萎病菌的抑菌带宽度分别达12.67和11.67 mm;不同拮抗细菌菌株间的代谢物对香蕉枯萎病菌的抑制率存在差异,其中菌株NJ-1和NJ-4的抑菌效果较好,抑制率分别达89.06%和88.47%。菌株NJ-1和NJ-4对12种植物病原真菌均具有较好的抑制作用,抑菌谱广,且对5%的香蕉枯萎病菌粗毒素具有一定的耐受性。经菌落形态、生理生化特征及分子鉴定,菌株NJ-1和NJ-4分别为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)和贝莱斯芽孢杆菌(Bacillus velezensis)。盆栽试验结果表明,菌株NJ-1和NJ-4对香蕉枯萎病具有较好的防治作用,其防治效果分别为71.69%和70.75%,且与对照药剂450 g/L咪鲜胺水乳剂1000倍液处理相比,菌株NJ-1和NJ-4对促进香蕉苗株高、根长生长有显著优势。【结论】菌株NJ-1和NJ-4对香蕉枯萎病具有高效的生防潜力,而且对香蕉生长具有一定的促进作用。

香蕉根际微生态及其与枯萎病防治之间的关系

枯萎病严重危害香蕉生产,可致香蕉大幅减产甚至绝收。该病害通过土传、种苗调运等途径进行传播扩散,其病原菌产生的厚垣孢子在土壤中存活的时间长达30年,防治非常困难,是政府、学术界和产业界高度关注的对象之一。为了攻克这一难题,国内外科研工作者及相关从业者进行了广泛而深入的研究。本文从香蕉枯萎病的发生与危害、植物根际微生态及其与土传病害的关系、香蕉根际微生态及其在枯萎病防治中的作用和贡献等方面进行综述,并对其研究趋势进行了展望,以期为后续香蕉根际微生态的深入研究、优良生防资源的挖掘与创新利用及香蕉枯萎病的有效防治提供参考。

复合生防菌对香蕉枯萎病的防效及其促生作用

香蕉枯萎病是香蕉生产上重要土传病害,生物防治是目前预防该病害发生的有效途径之一。通过不同生防菌平板生长共培养法和发酵液抑菌活性测定法,获得1组复合生防菌(解淀粉芽孢杆菌NJ-1+木霉菌T05-49)。采用发酵液灌根法测定了复合生防菌(NJ-1+T05-49)对香蕉枯萎病的防治效果、促生作用以及对根际土壤微生物种群数量的影响。结果表明:复合生防菌、解淀粉芽孢杆菌NJ-1和木霉菌T05-49发酵液对香蕉枯萎病的防效分别为78.92%、66.46%和52.46%。与解淀粉芽孢杆菌NJ-1和木霉菌T05-49发酵液相比,复合生防菌处理对病害的防效分别提高了18.75%和50.43%,株高和主根长度的增幅分别达9.22%、26.87%和8.58%、21.95%。复合生防菌处理21 d后,根际土壤中细菌和放线菌数量分别为9.10×10^(6)cfu·g^(−1)和20.83×10^(5)cfu·g^(−1),真菌数量仅为0.70×10^(3)cfu·g^(−1),细菌和放线菌的数量得到显著的增加。研究结果为复合生防菌(NJ-1+T05-49)在香蕉枯萎病生物防治上的开发应用提供依据。

物理诱变技术在提升有益微生物拮抗香蕉真菌病原菌方面的研究进展

香蕉真菌性病害是香蕉生产中的主要病害之一,可严重阻碍香蕉产业的可持续发展。而生物防治技术,尤其是利用生防菌的策略,为该问题提供了一个可持续的解决方案。尽管生物防治具有潜在的应用前景,但生防菌在田间的有效定殖和稳定防病能力仍是挑战。本研究聚焦于物理诱变技术对生防菌的改良效果,旨在提升其对香蕉真菌性病原的拮抗能力。利用物理诱变技术对生防菌株进行诱变改良可显著提高生防菌对寄主的定殖能力和病害的防治效果。为了明确物理诱变技术对提升生防菌田间防效的作用,本文综合分析了不同物理诱变技术的类型、作用机理以及它们在提升生防菌拮抗真菌病原体中的应用。同时,文中还探讨了突变菌株筛选与鉴定的方法,并对比了各技术的优缺点。特别指出了传统物理诱变技术在控制突变方向、提高效率及稳定性方面的局限,并提出了离子束、脉冲强光和空间诱变等新型物理诱变技术的潜在优势。通过归纳现有研究和展望未来发展方向,本文旨在为物理诱变技术在增强生防菌对植物病害防治效果的应用提供理论依据,并对其在未来香蕉真菌性病害管理中的应用潜力进行展望。

香蕉枯萎病4株生防菌株的诱变改良及抑菌机制初探

香蕉是我国亚热带地区重要的经济作物之一,而香蕉枯萎病的发生严重阻碍了香蕉产业的发展。生物防治技术因其绿色环保、持久抗病等特点,已成为近年来香蕉枯萎病防治的研究热点之一。防病高效、作用机制多样的生防菌株是香蕉枯萎病生物防治的重要基础。本研究通过对已获得的4株不同种类的生防菌进行紫外-亚硝酸钠复合诱变,得到了具有良好防效的诱变菌株,抑菌活性最高提升186.24%,防治效果最高提升46.54%。对得到的4株诱变株的防病机制进行了初步探究,结果表明:菌株Ba62v对香蕉枯萎病菌的菌落生长抑制率最高,同时还可以诱导香蕉苗中SOD活性;菌株Blz02v对香蕉苗具有较好的促生作用,同时可以诱导香蕉苗的POD和SOD活性;菌株Bc11v对病菌的孢子萌发抑制率最高,同时可诱导香蕉苗的PPO、CAT和SOD活性;菌株Pt05v对病菌的产孢抑制率最高,同时可诱导香蕉苗的POD、PPO和SOD活性。4株生防菌诱变株对病原菌和寄主的主要作用机制各不相同,存在复配增效的生防潜力,为今后抗病复合菌剂的开发利用提供了重要的菌株资源,具有良好的应用前景。

不同中草药植物提取物对香蕉枯萎病菌抑菌活性评价

【目的】探究不同中草药提取物对香蕉枯萎病菌的抑菌效果,筛选防治香蕉枯萎病的有效植物资源。【方法】选取大黄、穿心莲等29种中草药,采用乙醇浸提法提取中草药植物中的有效活性成分,应用生长速率法检测各提取物对香蕉枯萎病菌4号生理小种(Foc TR4)的抑制作用,使用石油醚、氯仿、乙酸乙酯、正丁醇4种不同极性溶剂对大黄的乙醇粗提物进行分级萃取,利用悬滴法测定提取物对香蕉枯萎病菌孢子萌发的抑制作用,并观察提取物对香蕉枯萎病菌菌丝形态的影响。【结果】29种中草药提取物对Foc TR4的抑菌效果表现出较大差异,大黄、穿心莲、苦参、野菊花4种提取物对Foc TR4的抑菌效果较好,其中大黄提取物的抑制作用最佳,6 mg/mL大黄提取物的抑菌率为48.57%,对菌丝生长的EC_(50)值为6.68 mg/mL,抑制孢子萌发的EC_(50)值为4.60 mg/mL;通过光学显微镜观察,大黄提取物对Foc TR4菌丝具有一定破坏作用,使菌丝产生大量分枝和黏连并造成菌丝生长不均匀等现象;大黄乙醇粗提物的石油醚、氯仿、乙酸乙酯、正丁醇4个萃取组分中,乙酸乙酯萃取组分对Foc TR4菌丝生长和孢子萌发抑制效果最佳,其浓度为10 mg/mL时,对菌丝生长的抑制率可达85.68%;大黄提取物乙酸乙酯萃取组分对Foc TR4菌丝生长的EC_(50)值为0.16 mg/mL。【结论】从29种中草药提取物中筛选出了抑菌效果较好的大黄提取物,并进一步明确其对香蕉枯萎病菌Foc TR4的主要有效抑菌成分在乙酸乙酯萃取组分中,可为研发防治香蕉枯萎病的植物源新农药提供参考。

香蕉枯萎病无人机多光谱影像数据集

香蕉枯萎病被称为香蕉“癌症”,目前已严重威胁着全球香蕉生产。及时精准地识别香蕉枯萎病植株对疫株除治及农业种植结构优化调整具有重要意义。为探究香蕉枯萎病的无人机遥感识别方法,本研究在广西隆安县的一个香蕉种植农场,选择有香蕉枯萎病发生的区域,获取了香蕉枯萎病遥感综合实验数据,经过整理和预处理制作了本数据集。本数据集包含了无人机多光谱反射率数据和香蕉枯萎病发生状况地面样点调查数据,无人机多光谱影像数据采集时天气晴朗、无云且光照充足,飞行高度120 m,空间分辨率8 cm/pixel;香蕉枯萎病发生状况样点调查采用过高精度手持GPS单元进行样点经纬度信息采集,并在室内将地面调查样点位置与无人机影像上对应香蕉植株的中心位置进行匹配。本数据集的无人机多光谱影像数据空间分辨率高,地面样点调查数据准确,可应用于香蕉枯萎病无人机遥感识别与监测相关研究,对促进农作物病害遥感监测研究及应用具有重要意义。

抗香蕉枯萎病菌菌株F2-14的鉴定及其抑菌机制初探

香蕉枯萎病已严重威胁全球香蕉产业发展,生物防治是防控香蕉枯萎病的重要途径之一。本研究筛选香蕉土壤中的拮抗香蕉枯萎病菌(Fusarium oxysporum f.sp.cubense tropical race 4,Foc TR4)活性细菌,得到1株具有高拮抗活性的菌株F2-14。采用生理生化特性、形态特征和基因组ANI值分析鉴定该菌株,并进行其生物信息学分析,利用antiSMASH预测其次级代谢产物合成基因簇,与CAZy等数据库进行比对分析;并进行其抑菌物质粗提及其抑菌机制研究。结果表明,菌株F2-14鉴定为贝莱斯芽孢杆菌Bacillus velezensis。其基因组中具有产生几丁质酶、葡聚糖酶、蛋白酶等的基因,还含有编码杆菌溶素、儿茶酚型嗜铁素、丰原素、表面活性肽等7种抗菌活性的基因簇。菌株F2-14具有广谱抗真菌活性,能够平板抑制辣椒炭疽病菌Colletotrichum acutatum等15种病原真菌菌丝生长,且能通过产生次级代谢物致使Foc TR4病菌的细胞壁破裂和细胞膜受损,从而抑制Foc TR4病菌生长。说明贝莱斯芽孢杆菌菌株F2-14在植物病害防控方面有着较好的应用潜力。

香蕉HOS15基因的鉴定及枯萎病菌胁迫下的表达分析

为了研究HOS15(HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENES 15)是否参与香蕉抗性调控过程,利用拟南芥HOS15蛋白序列,采用多种生物信息学分析工具,对香蕉HOS15(MaHOS15)基因进行鉴定;以高抗品种‘南天黄’和易感品种‘威廉斯’为试验对象,研究MaHOS15在枯萎病菌胁迫下的表达分析及其调控植物病害的潜在机制。结果表明:MaHOS15蛋白中LisH结构域和WD40重复蛋白序列高度保守;MaHOS15蛋白二级结构具有α螺旋、β折叠、延伸链和无规卷曲结构,且以无规卷曲为主,占比为46.2%;亚细胞定位发现MaHOS15在细胞核内,推测MaHOS15可能在细胞核内参与香蕉枯萎病的调控;MaHOS15可能响应SA信号通路、MeJA信号通路和脱落酸反应;推测MaHOS15是在植物抗病过程中负调控植物对病原体防御的关键基因。

香蕉枯萎病抑病菌群的构建及其生防效果研究

[目的]为实现香蕉枯萎病的有效防控,本研究拟构建对香蕉枯萎病具有抑制作用的生物防治菌群。[方法]利用平板对峙法从香蕉枯萎病的抑病型土壤中分离筛选对香蕉枯萎病菌(尖孢镰刀菌古巴专化型4号生理小种)具有抑制作用的菌株,并通过16S rRNA测序技术对菌株进行鉴定,通过室内培养试验测定菌株产生长素和生物膜形成能力,结合室内共培养试验和盆栽试验探究构建的菌群对香蕉枯萎病的抑制作用。[结果]分离筛选到的4株拮抗菌均对香蕉枯萎病菌表现出较强的抑制作用,16S rRNA序列检测结果表明,其分别为芽胞杆菌(Bacillus sp.)、链霉菌(Streptomyces sp.)、芽胞杆菌(Bacillus sp.)、肠杆菌(Enterobacter sp.);室内培养试验发现,分离筛选的4株拮抗菌具有较强的产生长素和生物膜形成能力;体外共培养研究结果进一步发现,由4株菌组成的合成菌群表现出最强的抑制效果,相比于对照,抑菌率增加了93.6%;盆栽试验证实该合成菌群能有效在香蕉植株根际定殖,并显著降低病原菌数量,相比于对照,其病原菌数量降低了92.13%。[结论]成功分离筛选并构建了一个由4株细菌组成的抑病菌群,盆栽条件下其能明显抑制香蕉枯萎病病原菌的增殖,为利用有益微生物防控香蕉枯萎病提供了一定的技术支撑。

香蕉镰刀菌枯萎病研究进展

就香蕉镰刀菌枯萎病在全球的分布与危害、症状、主要扩散原因、抗病育种、抗病机制的研究以及所采取的 防治措施作一概述,以期促进我国香焦镰刀菌枯萎病抗性育种及综合防治的深入研究。香蕉镰刀菌枯萎病是一种由 土壤真菌引起的毁灭性病害,目前正严重危害世界香蕉生产,从而引起广泛关注和深入研究。抗病育种被认为是解 决香蕉镰刀菌枯萎病危害的根本措施,其中突变育种、杂交育种、基因工程育种和体细胞杂交育种等领域的研究取 得了较多的成果。而抗病品种的抗病机制的研究才刚刚起步,可能是物理阻碍和化学抑制相互作用的结果。

香蕉枯萎病致病菌筛选及致病菌浓度对香蕉枯萎病的影响

【目的】通过筛选和鉴定香蕉枯萎病的致病菌株,之后接种不同浓度的病原菌孢子悬液,研究香蕉植株的发病程度,以期为香蕉枯萎病的田间诊断提供科学的理论依据。【方法】采用室内筛选和盆栽试验相结合的方法。【结果】从香蕉枯萎病病株的假茎基部分离筛选纯化获得了一株致病的尖孢镰刀菌菌株。盆栽回接该菌株35d后,有90%香蕉植株发病,香蕉死亡率高达70%,经鉴定确认该菌株为香蕉枯萎病致病菌(Fusarium oxysporum f.sp.cubense,FOC);本试验条件下,致病菌株的孢子悬液浓度为103CFU/g土时是香蕉枯萎病发病的临界浓度,当致病菌株的孢子悬液浓度不超过105CFU/g土时,香蕉枯萎病的发病指数随着病原菌孢子悬液浓度的加大而增加,当致病菌株的孢子悬液浓度超过105CFU/g土时,香蕉枯萎病的发病指数不再显著变化;香蕉根际土壤和土体土壤中的尖孢镰刀菌数量受致病菌株孢子悬液不同浓度的影响较大,接种病原菌孢子悬液不同浓度处理的根际土壤的尖孢镰刀菌数量是土体土壤尖孢镰刀菌数量的1.15—2.06倍,显著高于土体土壤尖孢镰刀菌数量。【结论】香蕉植株枯萎病是否发生与土壤本身的尖孢镰刀菌数量有关,发病程度高低决定于根际土壤中的尖孢镰刀菌数量,以上结果可为香蕉枯萎病的诊断提供科学的理论依据。

生物肥与甲壳素和恶霉灵配施对香蕉枯萎病的防治效果

通过盆栽试验研究了生物肥与甲壳素和恶霉灵配施防治香蕉枯萎病效果,试验结果表明,生物肥与恶霉灵配施(H+F)处理香蕉枯萎病病情指数最高,生物肥与甲壳素配施(C+F)处理病情指数最低。单独生物肥处理防病效果为32.8%,生物肥与甲壳素配施处理为42.5%,而生物肥与恶霉灵配施加重了香蕉枯萎病病情。Biolog Eco微平板研究发现,AWCD(平均每孔颜色变化率)和Shannon等4个多样性指数变化趋势与防病效果相反:防病效果好的处理,土壤细菌功能多样性指数反而低,经检测发现病原真菌(Fusarium oxysporum f.sp.cubense)可利用Biolog Eco微平板上碳源底物并发生颜色变化,干扰测定结果。T-RFLP分析土壤细菌DNA多样性,对照(灭菌生物肥)土壤中TRFs末端限制性片段最少,生物肥与甲壳素配施处理最多。与网上数据库比较,生物肥与甲壳素配施增加了土壤中芽胞杆菌种类,与恶霉灵配施降低了芽胞杆菌种类。分析发现,T-RFLP和Biolog的主成份分析载荷图具有较高一致性。因此,生物肥与生物农药甲壳素配施,从生态角度控制土传病害,优势互补,提高了土壤细菌多样性,改善了土壤细菌群落结构,有利于提高防病效果。

土壤快速强烈还原对于尖孢镰刀菌的抑制作用

香蕉枯萎病是由尖孢镰刀菌古巴专化型(Fusarium oxysporum f.sp.cubense,FOC)引起的一种世界性的土传病害,每年造成大量的经济损失,目前尚未找到有效的防治办法。实验采取土壤淹水及添加有机物料的方法,抑制土壤中FOC的数量。结果表明:土壤淹水处理在第5天显著增加了土壤的pH值,但随着处理时间的增加,淹水的处理中土壤pH值逐渐下降;土壤淹水及添加有机物料显著降低了土壤中SO2-4和NO-3的浓度;土壤中添加秸秆、猪粪和石灰的处理显著增加了土壤中NH+4的浓度。土壤淹水及添加有机物料对于土壤中可培养细菌数量无显著影响;但显著降低了土壤中可培养放线菌和真菌的数量;土壤淹水及添加秸秆、甘蔗渣和石灰的处理显著降低了土壤中FOC的数量,其中添加高量秸秆处理中FOC的数量下降最多,仅为处理前土壤中FOC数量的2.88%。添加有机物料但未加石灰的处理土壤中总微生物量较处理前相比显著增加。研究表明土壤淹水及添加有机物料是一种可以防控香蕉枯萎病的高效和环保的方法。