两种沉水植物在不同水深和生长时期对入侵植物的响应

为研究沉水植物在不同水深和生长时期对不同种类入侵植物的响应,选取2种湿地入侵植物凤眼莲Eichhornia crassipes、水盾草Cabomba caroliniana和2种常见本地沉水植物黑藻Hydrillaverticillata、菹草Potamogeton crispus为研究对象,通过模拟试验探究在不同水深（0.2、0.4 m）和生长时期（生长初期和生长旺期）的本地沉水植物对2种入侵植物的响应。结果显示,当水深为0.4 m时更有利于黑藻的生长,并可削弱入侵植物对黑藻生长的消极作用,而水深对菹草的生长无显著影响;入侵植物种类对本地沉水植物的生长无显著影响,但影响方式却存在差异,其中水盾草倾向于直接抑制本地沉水植物的生长,而凤眼莲可以通过降低水体透明度以及总磷含量进而间接抑制本地沉水植物的生长。此外,外来植物在本地沉水植物生长初期入侵对本地沉水植物产生的消极影响较生长旺期入侵时更显著。表明凤眼莲及水盾草入侵对本地沉水植物生长的影响机制存在差异,本地沉水植物在适宜水深和生长旺期对2种入侵植物具有更强的抵抗能力。     

四种替代药剂对梨火疫病菌的抑制活性及其田间防效

为筛选农用链霉素替代药剂,以其为对照药剂,测定春雷霉素、中生菌素、噻霉酮和噻菌铜这4种常用细菌病害防治药剂对梨火疫病菌Erwinia amylovora的抑制活性、对梨火疫病的田间防效及不同药剂处理后梨中的农药残留,并对这4种药剂的作物安全性进行评价。结果表明,中生菌素、噻霉酮和春雷霉素对梨火疫病菌有抑制作用,抑制中浓度EC50分别为1.60、6.64和60.57 mg/L,中生菌素的抑制效果高于链霉素。在连续2年田间试验中,中生菌素1 000倍液和春雷霉素400倍液对梨火疫病的保护效果和治疗效果均达90.33%以上,噻霉酮500倍液和噻菌铜200倍液对梨火疫病的保护效果均达100.00%,治疗效果均超过86.97%,与对照药剂农用链霉素2 000倍液的效果相当。所有药剂处理后均未检出中生菌素、春雷霉素、高效氯氰菊酯和农用链霉素的农药残留,而噻虫嗪、阿维菌素和矮壮素虽有检出,但其残留量均低于国家限量标准。花期前后、幼果期和果实膨大期施药,中生菌素、春雷霉素、噻霉酮和噻菌铜对梨花、叶片、枝梢及果实生长均无不良影响。综合来看,中生菌素、春雷霉素、噻霉酮和噻菌铜均可作为农用链霉素的替代药剂,...     

Application and mechanisms of metal-based nanoparticles in the control of bacterial and fungal crop diseases

Nanotechnology is a young branch of the discipline generated by nanomaterials. Its development has greatly contributed to technological progress and product innovation in the field of agriculture. The antimicrobial properties of nanoparticles (NPs) can be used to develop nanopesticides for plant protection. Plant diseases caused by bacterial and fungal infestations are the main types of crop diseases. Once infected, they will seriously threaten crop growth, reduce yield and quality, and affect food safety, posing a health risk to humans. We reviewed the application of metal-based nanoparticles in inhibiting plant pathogenic bacteria and fungi, and discuss the antibacterial mechanisms of metal-based nanoparticles from two aspects: the direct interaction between nanoparticles and pathogens, and the indirect effects of inducing plant resilience to disease. © 2022 Society of Chemical Industry.     

Challenges and opportunities of unmanned aerial vehicles as a new tool for crop pest control

The application of pesticides is not simply delivering chemicals to the target area. It also involves considering the negative aspects and developing strategies to deal with them during the application process, to ensure the maximization of pesticides use efficiency and the maintenance of the ecosystem. Unmanned aerial vehicle (UAV) sprayers demonstrate unique advantages compared to traditional ground sprayers, particularly in terms of maneuverability and labor intensity reduction, showed great potential for chemical application in pest control. It is undeniable that there exist challenges in the practice of UAV spraying, such as higher potential risks of pesticide drift or pathogen transmission, uncertainty canopy deposition for different crops, and unexpected leaf breakage induced by downwash flow. Maximizing the utilization of downwash flow while avoiding lateral air movement outside the intended target crop area is a major issue for chemical application with UAV sprayers, particularly in light of the increasingly apparent consensus on the need for enhanced environmental protection during the chemical application process. It must be considered that the operation strategy in different scenarios and for different crop targets is not the same, unique requirements should be given on nozzle atomization, flight parameters, adjuvants and aircraft types in specific working situations. In future, the implementation of spray drift prediction, technical procedures development, and other solutions aimed at reducing pesticide drift and improving deposition quality, is expected to promote the adoption of UAV sprayers by more farmers. © 2023 Society of Chemical Industry.     

巨大芽胞杆菌YB-3的筛选、鉴定及其对生姜青枯病的生防效果研究

青枯病（bacterial wilt）是生姜上的一种细菌土传毁灭性病害,化学防治易污染环境且常规化学药剂很难在土壤中起到持续控病的作用,生物防治是其理想的防治方法。为开发对生姜青枯病有效的生防措施,对从生姜根际土壤中分离的一株生防细菌YB-3进行了鉴定,并对其生物学特性及生防效果进行了研究,以丰富生防菌株资源库。采用抑菌圈法筛选拮抗细菌,对效果最好的拮抗菌株做盆栽试验,测定其对生姜青枯病的防治效果,根据形态特征、生理生化特性以及16S rDNA序列对筛选得到的优良菌株进行鉴定。试验结果表明,该拮抗菌在平皿上对青枯菌的抑菌率为50.67%,盆栽试验对青枯病的防治效果为60.86%;经16S rDNA序列分析,并结合形态学和生理生化特征,将菌株YB-3鉴定为巨大芽胞杆菌Bacillus megaterium。YB-3是一株具有开发利用价值的姜青枯病生防菌株。     

苜蓿地撂荒过程中土壤-微生物-胞外酶及化学计量的变化

紫花苜蓿(Medicago sativa L.)作为优良修复草种在黄土高原广泛种植,然而随着农村人口迁移及土地利用变化,苜蓿人工草地大量弃置的问题已引起广泛关注。为研究苜蓿弃置草地土壤质量变化规律,本研究分析了不同弃置年限(0年、5年和10年)苜蓿草地土壤养分、微生物量、参与土壤碳氮磷(C,N,P)循环的胞外酶活性及其化学计量变化。结果表明：总体上,土壤和微生物C,N含量随弃置年限呈增加趋势,而C,N相关胞外酶活性和化学计量变化幅度较小;土壤和微生物P含量随弃置年限增加而显著降低,但P相关胞外酶活性及化学计量均有不同程度的增加。进一步分析发现：相较于其他土层,表层(0～20 cm)土壤C,N,P含量及其酶活性较高,其变化趋势与总体结果相似;亚表层土壤(20～40 cm)和(80～100 cm)深层土壤C,N,P含量及其酶活性呈先增后减趋势,且各指标较于表层土壤均降低40%～80%。相关分析表明弃置草地土壤由于P匮乏而逐步退化,可通过补施磷肥改善。     

动物防疫领域政府购买公共服务相关术语混合使用情况辨析

自1994年深圳市罗湖区在环境卫生领域率先引入政府购买公共服务以来,我国政府购买公共服务经历局部性试点与探索、试点推进、制度化推广、全面推开与创新等4个阶段。2005年以来,我国对动物防疫领域政府购买公共服务进行了探索,但有关术语及其涵义一直未界定,更未形成共识,导致术语混用较为严重。术语混用体现了人们认知不同,看法不一,给动物防疫领域政府购买公共服务理论研究和实践探索造成了混乱。鉴于此,本文尝试梳理术语混用的背景、混用情况并予以辨析,以探讨动物防疫领域政府购买公共服务相关术语的正确使用。