Plantain Bananas PIF Seedlings Treatment with Liquid Extracts of <i>Tithonia diversifolia</i>Induces Resistance to Black Sigatoka Disease

Plantain bananas culture encounters the problems of seedlings quantity and quality unavailability. Black Sigatoka Disease (BSD) is one of the main pathological constraints of banana that can severely reduce the photosynthetic leaf area, leading to the losses of production of about 50% in banana plantation. The use of liquid extracts of Tithonia diversifolia could potentially induced the resistance of the PIF seedlings to BSD during the vegetative stages in the nursery. The aim of this work was to evaluate the effect of Tithonia diversifolia liquid extracts against the development of BSD on the PIF plantain bananas seedlings. The explants in the greenhouse and the seedlings in the shade were watered with liquid extracts of T. diversifolia during the process of PIF seedling production in sterile and non-sterile conditions. The treated seedlings show a more effective enhancement of seedlings quality parameters and also induce resistance against BSD. The vegetative stages parameters (the number of shoots, the diameter and the height of shoots, the foliar area, the length and weight roots) were improved in treated seedlings compared to controls ones. The treated seedlings showed maximum protection against BSD of up to 87% compared to controls. They also exhibited an increase in the accumulation of total proteins and total phenolics, as well as the activity of defense-related enzymes (peroxidase, polyphenol oxidase and glucanase). The treatment seems to acts as a vital stimulator and could therefore be a useful tool for small holder farmers favouring an eco-friendly agriculture using fewer synthetic inputs.

Potential Biostimulant Effect of Clam Shells on Growth Promotion of Plantain PIF Seedlings (<i>var</i>. Big Ebanga &Batard) and Relation to Black Sigatoka Disease Susceptibility

Plantain contributes significantly to income generation and food security for millions of people in the world. However, it faces problems of seedlings quantity, quality and availability. The innovation of the “plants issus de fragments de tiges” (PIF) technique could be a solution to these problems for small holders’ farmers. The aim of this research is to evaluate the effect of clam shells through amendment of Batard and Big Ebanga PIF substrate, on the growth promotion of seedlings and their protection against black Sigatoka disease (BSD). Plantain PIF seedlings of the two varieties were grown in a substrate amended with 1% concentration of the clam shells powder in the presence of negative control in the sterile and non-sterile conditions. Agromorphological characteristics, susceptibility level to BSD, total proteins and polyphenols content were assessed. Because of the presence of clam shells in the substrates, explants germinated quickly, generated high number of shoots, grew taller by 32%, with a diameter of pseudo stems of 30%, and area of leaves of 18% compared to control. In addition, the seedlings were less susceptible to BSD by 73% compared to those of controls. The treatment seems to allow the accumulation of larger amounts of total proteins and polyphenols before inoculation and after inoculation that could participate in the growth promotion and the reduction of plant’s susceptibility level. Clam shells treatment acts as a biofertilizer/biopesticide and could be helpful to boost production of plantain seedlings, the use of the by-products of fishing in agriculture and helps alleviate poverty of small holders’ farmers.

Field Efficacy of a Biopesticide Based on <i>Tithonia diversifolia</i>against Black Sigatoka Disease of Plantain (<i>Musa</i>spp., AAB)

Black Sigatoka disease (BSD) is a foliar disease caused by Mycosphaerella fijiensis, responsible of reduction of the photosynthetic area of banana plant and yield at harvest since it has an influence on fruit physiology. The control of BSD relies on the use of chemicals which are not affordable for the small holder farmers and increase the cost of production. Moreover, this chemical control is ineffective, negatively impacting the environment and human health, and is at the origin of strain resistance. Tithonia diversifolia is known as rich in many compounds such as mineral elements, defense metabolites, some phytochemicals;and it is increasingly used in agriculture. Recently, the protective effect of Tithonia diversifolia liquid extract against BSD development on plantain vivoplants in the nursery was highlighted. The aim of our study was to evaluate the efficacy of a biopesticide base on Tithonia diversifolia on the BSD development in a plantain field under high disease pressure. The effect of Tithonia diversifolia biopesticide on Mycosphaerella fijiensis mycelial growth in vitro was evaluated. An experimental field at the flowering stage was selected and treated with the biopesticide base on Tithonia diversifolia at three different concentrations: undiluted (100%), diluted at 1/2 (50%) and diluted at 1/4 (25%) for 17 weeks. The disease severity, the number of functional leaves, the youngest spotted leaf (YSL) and the youngest necrotic leaf (YNL) were evaluated in course of time. The biopesticide treatments significantly (P < 0.001) reduce the BSD severity in course of time, but it is more effective for the most diluted concentration (25%). The number of leaves increases in course of time as well as the rank of the YSL and the YNL confirming the efficiency of BSD control. The efficacy of this biopesticide base on Tithonia diversifolia could be a hopeful ecoresponsible solution for the plantain sector in general and in particular for poor small farmers.

香蕉叶斑病的研究进展

近几年来,随着国内外技术壁垒的逐步建立,香蕉叶斑病逐渐成为制约国内香蕉市场开放的一个重要的因素,对其病原菌的各项基础研究是充分了解病原-寄主互作及其抗病机制研究的前提。根据国内外近年来香蕉叶斑病的研究概况,对香蕉叶斑病的历史、主要症状、病原菌的分类及生物学特性、病原菌的分离、监测和鉴定技术、病害的流行条件及防治方法进行了综述。认为,目前为了提高国际市场的地位,对外来有害生物进行高效预防,国内外对香蕉叶斑病研究的重点集中在对病害的早期检测和有效预防上;在对病原和作物互作机制的研究方面,根据其他病原菌的研究模式,应用分子生物学技术和传统的植物病理学研究方法结合,在理论和实践上进行相互论证,是推进香蕉叶斑病深入研究的重点。

25%凯润乳油对香蕉叶斑病的毒力测定及防治试验

香蕉尾孢菌叶斑病是香蕉的重要病害，该病在华南蕉区每年6～11月大量发生，危害严重。2002-2004年进行的新型杀菌剂25％凯润乳油对香蕉尾孢菌毒力测定、防治叶斑病药效试验研究结果表明，25％凯润乳油对香蕉尾孢菌的抑菌效果明显，对香蕉叶斑病有良好的防治效果，对香蕉安全；第三次施药后20天，25％凯润乳油1000倍的防治效果达到83．27％，显著优于25％敌力脱乳油1500倍的防效。目前，该药剂已正式登记用于防治香蕉叶斑病，建议在生产上推广使用。

50%醚菌酯干悬浮剂对香蕉尾孢菌叶斑病的毒力测定与防治试验

香蕉尾孢菌叶斑病是香蕉上的重要病害,每年夏秋季节在华南蕉区普遍发生,危害严重。2003￣2004年进行新型杀菌剂50%醚菌酯干悬浮剂对香蕉尾孢菌的毒力测定和防治叶斑病药效试验,结果表明,50%醚菌酯干悬浮剂对香蕉尾孢菌的抑菌效果明显,对香蕉叶斑病有良好的防治效果,对香蕉安全;第3次施药后15 d,50%醚菌酯干悬浮剂1 500倍的防治效果达到82.67%,显著优于对照药剂25%敌力脱乳油1 500倍的防效,建议在生产上推广使用。

20.67%万兴乳油对香蕉叶斑病的毒力测定与防治试验

香蕉尾孢菌叶斑病是危害香蕉的重要病害之一,在华南香蕉产区夏秋生长季节大量发生,严重危害香蕉叶片。2001～2003年进行的新型复配杀菌剂20.67%万兴乳油对香蕉尾孢菌的毒力测定及对香蕉叶斑病的防治试验研究结果表明,20.67%万兴乳油对香蕉尾孢菌的抑制效果明显,对香蕉叶斑病防治效果优良,且对香蕉安全,施药3次的防治效果达81.23%～83.33%,优于对比药剂25%敌力脱乳油1 500倍的防效,是一种具保护兼治疗作用的高效杀菌剂,值得在香蕉生产上推广使用。

4种诱导剂对香蕉抗褐缘灰斑病的诱导作用

【目的】明确氨基寡糖素、异噻菌胺和禾之壮有机水溶肥对香蕉抗褐缘灰斑病的诱抗作用,为利用诱导剂防控香蕉褐缘灰斑病提供理论和实践依据。【方法】采用叶喷、叶喷+根施、根施3种施药方式,研究了4种植物诱导剂对香蕉褐缘灰斑病抗性的诱导作用。【结果】4种供试诱导剂对香蕉褐缘灰斑病均有较好的诱抗效果。3种施药方式中以叶喷+根施处理效果最佳,5%氨基寡糖素AS、20%异噻菌胺SC、77%异噻菌胺WG及禾之壮有机水溶肥第3次药后7d的诱抗效果分别为70.02%、72.62%、63.61%和67.67%;3次药后的平均防效分别为53.18%、56.68%、42.16%和53.34%。其次在叶喷、根施处理条件下,20%异噻菌胺SC与禾之壮有机水溶肥第3次药后7d的诱抗效果也均超过63%,其中禾之壮有机水溶肥根施处理第3次药后4次调查的平均防效为52.33%。禾之壮有机水溶肥根施处理抗病效果下降最慢,随后依次是叶喷+根施处理条件下的禾之壮有机水溶肥、20%异噻菌胺SC和5%氨基寡糖素AS,持效期28d以上;77%异噻菌胺WG根施处理诱抗效果下降最快,持效期最短,7~14d,其余各处理持效期为14~21d。【结论】5%氨基寡糖素AS、20%异噻菌胺SC及禾之壮有机水溶肥的叶喷+根施、禾之壮有机水溶肥根施对香蕉褐缘灰斑病具有良好的诱导抗病效果,持效期28d以上。

氯氟醚菌唑·吡唑醚菌酯对香蕉叶斑病的田间药效评价

为有效防治香蕉叶斑病,筛选具有较好防治效果的杀菌剂。笔者以400 g/L氯氟醚菌唑·吡唑醚菌酯为试验药剂,在2018年和2019年开展了防治香蕉叶斑病的田间药效试验。试验表明,在香蕉叶斑病发病初期进行茎叶喷雾施药,133.3 mg/kg的试验药剂在3次药后的平均防效在2018年和2019年分别为74.08%和74.54%,明显优于对照药剂中133.3 mg/kg的400 g/L氯氟醚菌唑悬浮剂、166.7 mg/kg的吡唑醚菌酯乳油和丙环唑乳油;而200 mg/kg的400 g/L氯氟醚菌唑·吡唑醚菌酯悬浮剂在3次药后的平均防效可达79.68%和79.93%。说明400 g/L氯氟醚菌唑·吡唑醚菌酯悬浮剂对香蕉叶斑病的防治效果优良,是防治香蕉叶斑病的优良杀菌剂,值得在香蕉产区推广应用。

新型杀菌剂啶氧菌酯对香蕉叶斑病的防治效果

【目的】香蕉叶斑病是香蕉产业的重要病害,化学防治仍然是当前最为有效的防治手段。于2015—2016年连续2年开展香蕉叶斑病的田间化学防治试验,为生产上推广应用新型杀菌剂啶氧菌酯提供依据。【方法】试验设22.5%啶氧菌酯悬浮剂125、150和187.5 mg·kg^(-1),对照药剂250 g·L-1吡唑醚菌酯乳油125 mg·kg^(-1),以及空白对照共5个处理,3次药后第12或13天调查正常叶数、病叶数及病级,计算平均病指及平均防效。【结果】22.5%啶氧菌酯悬浮剂(有效成分用量125、150和187.5 mg·kg^(-1))2015年的防治效果分别为64.70%、68.16%和71.29%,2016年防治效果分别为68.44%、72.36%和76.29%。此外,在试验期间香蕉嫩叶未见药害现象,叶片生长均正常。【结论】22.5%啶氧菌酯悬浮剂是防治香蕉叶斑病的优良药剂,对香蕉比较安全,值得在香蕉产区推广应用。

海南香蕉褐缘灰斑病原菌的核酸分析鉴定

采用种的特异性引物,通过聚合酶链式反应(PCR)方法,对11个海南香蕉褐缘灰斑病菌菌株进行了鉴定。结果表明,11个菌株中,来自海南儋州、乐东、文昌、东方、澄迈、临高、琼海、昌江、琼山、三亚的10个菌株为Mycosphaerella fijiensis,而白沙菌株既不是M.fijiensis,也不是M.musicola,其Mycosphaerella种的分类地位有待进一步研究。采用随机扩增多态DNA(RAPD)分析,将这些菌株区别为2类,支持PCR鉴定结果。本研究的鉴定结果对指导海南综合治理香蕉褐缘灰斑病的的实践有参考作用。

50%丙环唑微乳剂的研制

对国内文献未见报道的50%丙环唑微乳剂配方的组成和制备方法进行了介绍,并测定了冷贮、热贮稳定性等理化性状及生物活性。田间药效试验结果表明,对香蕉叶斑病有较好的防效。

Assessing New Banana Genotypes for Relevant Traits: Implication for Variety Selection

Understanding the performance of new crop genotypes for traits of relevance is important in selecting potential cultivars to satisfy end-users. The objective of this study was to determine the performance of new banana genotypes for bunch mass (BMS) and BMS-related traits, resistance to black Sigatoka and sensory attributes. Eight cooking banana genotypes consisting of six new hybrid genotypes selected from advanced breeding trials and two control cultivars were evaluated in a randomized complete block design for three crop cycles at three locations in Uganda. Genotype, location, crop cycle and their interaction effects were significantly different for most traits assessed. The overall top two genotypes (“9058K-2” and “8099K-16”) combining high BMS, resistance to black Sigatoka and acceptable sensory attributes were identified. These genotypes are suggested as potential commercial cultivars for release to farmers in Uganda and/or other East African countries with similar environmental conditions to those where the genotypes were tested. It should be noted that high BMS/yield and resistance to diseases are not the only factors to consider when selecting banana genotypes that meet end-user needs. A combination of high BMS/yield, acceptable sensory attributes and resistance to diseases essentially influence the selection process of banana cultivars.

应用RAPD标记技术鉴定香蕉褐缘灰斑病菌

采用Mycosphaerella fijiiensis和M.musicola的RAPD标记技术鉴定海南香蕉褐缘灰斑病菌,结果表明,分离自海南儋州、乐东、文昌、东方、澄迈、临高、琼海、昌江、琼山、三亚香蕉上的10个菌株均为M.fijiensis,引起香蕉黑叶条斑病。

啶氧菌酯对香蕉叶斑病的防治效果研究

[目的]研究试验药剂250g／L啶氧菌酯悬浮剂经济有效的使用剂量和使用技术。[方法]在田间小区试验条件下，研究不同剂量试验药剂对香蕉叶斑病的防治效果。[结果]2009～2010年田间药效试验表明，250g／L啶氧菌酯悬浮剂对香蕉叶斑病具有较好防效，稀释1500倍连续用药3次的叶片末次防效达72％以上，果实末次防效达78％以上。[结论]250g／L啶氧菌酯悬浮剂是防治香蕉叶斑病较为理想的药剂。

25%丙环唑水乳剂防治香蕉叶斑病田间药效试验

2008年的田间试验表明,将25%丙环唑水乳剂稀释600倍、1000倍、2000倍进行喷雾,以25%丙环唑乳油1000倍为对照,通过调查病情指数计算防治效果。结果在稀释600～2000倍条件下,25%丙环唑水乳剂对香蕉叶斑病的防效为54.83%～77.16%,其中稀释1000倍的防效为61.94%～70.41%,与同等稀释倍数的25%丙环唑乳油的防效基本相当。

云南河口地区香蕉褐缘灰斑病的发生规律研究

对云南河口地区香蕉褐缘灰斑病（BananaSigatokaLeMSpotDisease）进行研究，结果表明：病害的发生、发展规律主要受温度和降雨量的影响；春季气温回升时开始发病，10～11月危害达到高峰值；不同地理环境危害程度有明显差异．病情指数东部地区（11．81）〉中南部地区（10．40）〉西部地区（7．94），但危害的基本规律是低海拔地区比高海拔地区先发病．且发病程度比高海拔地区严重，病情指数随着海拔的升高而降低。

50%丙环唑·左旋松油醇乳油防治香蕉叶斑病田间药效试验

2007-2008年的田间试验表明,50%丙环唑.左旋松油醇乳油可有效防治香蕉叶斑病,而且对香蕉安全。在稀释600-2000倍条件下,施药3次后该乳油对香蕉叶斑病防效为62.23%-77.27%。其中稀释1000倍液的防效为66.93%-74.52%,优于同等稀释倍数的25%丙环唑乳油,说明丙环唑和左旋松油复配可以提高防效。

香蕉褐缘灰斑病菌检测技术研究进展

香蕉褐缘灰斑病严重影响香蕉产量和品质,是香蕉生产上的重要生物灾害之一。香蕉褐缘灰斑病的早期诊断、检疫及防治的重要基础与前提是建立快速、灵敏的检测技术,从而准确及时鉴定出病原菌种类。本文介绍了香蕉褐缘灰斑病菌的种类和分类,概述了国内外香蕉褐缘灰斑病菌检测方法的研究进展,总结和归纳了传统、血清学、DNA指纹图谱、常规PCR、双重PCR、实时荧光定量PCR、LAMP及SPR免疫传感器等检测技术在该病病原菌检测中的应用,并比较分析了各种技术的特点,以期为选择合适的香蕉褐缘灰斑病菌检测方法提供参考。