325％苯醚甲环唑·嘧菌酯悬浮剂防治西瓜炭疽病田间药效试验初报

为筛选防治西瓜炭疽病的高效低毒药剂,本试验采用不同浓度的32.5%苯醚甲环唑·嘧菌酯SC进行西瓜炭疽病田间药效试验。结果表明,32.5%苯醚甲环唑·嘧菌酯SC在制剂用量为40 g/667m2、50 g/667m2时防治效果最好,防效分别为85.1%和85.9%。建议于西瓜炭疽病发病初期使用32.5%苯醚甲环唑·嘧菌酯SC 40～50 g/667m2喷雾防治,第一次施药后隔10 d再施药1次,共施3次,可有效防治西瓜炭疽病。     

5种药剂对西瓜炭疽病的田间防治效果研究

为筛选防治西瓜炭疽病的高效、低毒药剂,本研究通过田间试验的方法比较了啶氧菌酯、嘧菌酯、吡唑醚菌酯、苯醚甲环唑及苯甲·嘧菌酯5种药剂对西瓜炭疽病的控制效果.试验结果表明,啶氧菌酯150g/hm2、啶氧菌酯180g/hm2、嘧菌酯225g/hm2、吡唑醚菌酯150g/hm2、苯醚甲环唑60g/hm2以及苯甲·嘧菌酯195g/hm2在西瓜炭疽病发病初期施药,间隔7～10d施药1次,连续施药3次,末次药后7d的防效分别为68.81％～70.10％、71.22％～73.10％、61.65％～63.98％、70.67％～72.18％、73.29％～75.06％和69.68％～71.26％,嘧菌酯的防效略差于其他各处理,啶氧菌酯180g/hm2及苯醚甲环唑60g/hm2的防效略优于其他各处理,但各处理之间防效差异并不显著,5种药剂均能较好的防治西瓜炭疽病.     

25%嘧菌酯悬浮剂防治西瓜炭疽病试验

用25%嘧菌酯悬浮剂900~1 200倍液防治西瓜炭疽病效果较好,且对西瓜生长安全。在西瓜炭疽病发病初期开始施药,10 d施一次,连施3次,第二次药后10 d对西瓜炭疽病的防治效果达69.24%~77.13%。     

硅酸钠对葡萄炭疽病的防治效果

为探讨硅酸钠在室内和田间对葡萄炭疽病的防治效果,以巨峰葡萄为材料,对葡萄炭疽菌孢子萌发、菌丝生长速率及室内和田间防治炭疽病效果等进行测定。结果表明:不同浓度硅酸钠对葡萄炭疽菌的孢子萌发和菌丝生长均有抑制作用,且随浓度升高抑制作用增强;室内接种炭疽病菌5 d后,15、20和25 mmol/L硅酸钠对葡萄炭疽病的防治效果分别为30.58%、44.37%和52.71%,且抑制效果差异极显著;田间最后1次喷药10 d后,15、20和25 mmol/L硅酸钠对葡萄炭疽病的防治效果分别为66.94%、67.16%和73.46%,喷施10%苯醚甲环唑6次的防治效果为76.84%,喷施3次的防治效果为64.29%;25 mmol/L硅酸钠与喷施6次苯醚甲环唑的防治效果差异不显著,但与喷施3次苯醚甲环唑的差异极显著。研究表明,在生长季可利用硅酸钠与常规药剂交替使用来防治葡萄炭疽病。     

苹果采后炭疽病的化学防治技术

多菌灵、丙环唑、休菌清、苯醚甲环唑、异菌脲、禾纹清(多菌灵 丙环唑)六种供试药剂对苹果炭疽菌的生长都具有抑制作用，其有效浓度和作用方式有所不同。多菌灵、丙环唑、休菌清、苯醚甲环唑、异菌脲和禾纹清抑制菌丝生长的EC50分别为0．034、0．015、0．918、0．115、31．865和0．491∥rnl；抑制芽管伸长的EC50分别为0．4430、0．0240、0．3173、0．0991、154．88和0．2787蜉／rnl。对孢子萌发和芽管伸长的抑制率差异显著。六种药剂对苹果炭疽病的控制结果表明：丙环唑、禾纹清和苯醚甲环唑的防治效果较好，其中丙环唑和禾纹清的防治效果可达100％，而多菌灵、休菌清和异菌脲对果实的防治效果较低。药剂防治采用浸泡果实和喷雾两种方式，浸果的防治效果明显好于喷雾。     

咯菌腈与苯醚甲环唑等三种药剂复配对马铃薯早疫病菌（Alternaria solani）的联合毒力

采用菌丝生长速率法测定咯菌腈分别与丁香菌酯、吡唑醚菌酯或苯醚甲环唑3种药剂复配对马铃薯早疫病菌(Alternaria solani)的联合毒力,以Wadley公式评价咯菌腈与其他3种药剂复配对抑制早疫病菌菌丝生长是否有增效作用。通过田间试验验证咯菌腈与其他药剂有增效作用的桶混产品对马铃薯早疫病的防治效果。结果表明,咯菌腈与上述3种药剂按9种配比混合均无拮抗作用(增效系数均大于0.5),咯菌腈与苯醚甲环唑以5∶1复配有明显的增效作用(增效系数SR 2.02),与丁香菌酯或吡唑醚菌酯的9种配比混合物有加和作用(SR介于0.5与1.5之间)。在田间咯菌腈与苯醚甲环唑以5∶1桶混,并以105g/hm2的剂量施用,防效可达85%以上、增产率40%以上,显著高于同浓度单剂的防效和增产率。     

嘧菌酯等杀菌剂及其混配制剂对赤眼蜂的安全性评价

为明确嘧菌酯等杀菌剂及其混配制剂对赤眼蜂的毒性,评价含嘧菌酯混配制剂的风险性,本文采用管测药膜法测定了嘧菌酯等杀菌剂及其混配制剂对玉米螟赤眼蜂Trichogramma ostriniae的毒性,并进行安全性评价。结果表明:在杀菌剂单剂中,以嘧菌酯和百菌清对玉米螟赤眼蜂的毒性最高,LR50分别为1.31×10-4和9.59×10-4a.i.mg/cm2,为高风险药剂;丙环唑、苯醚甲环唑和己唑醇对玉米螟赤眼蜂的毒性较低,LR50分别是2.34×10-3、4.83×10-3和2.60×10-3a.i.mg/cm2,为中等风险性药剂;戊唑醇和烯酰吗啉的毒性最低,为低风险性药剂。在混配制剂中,只有嘧菌酯·百菌清对玉米螟赤眼蜂不安全,LR50是1.85×10-3a.i.mg/cm2,为高风险性药剂;嘧菌酯·己唑醇、嘧菌酯·烯酰吗啉和嘧菌酯·苯醚甲环唑对玉米螟赤眼蜂的毒性较低,LR50分别是8.96×10-4、3.17×10-3和1.65×10-2a.i.mg/cm2。嘧菌酯·丙环唑和嘧菌酯·戊唑醇对玉米螟赤眼蜂安全。两种杀菌剂混用对赤眼蜂生态风险性取决于单剂本身的毒性大小和在混剂中所占比例,嘧菌酯和高风险药剂混用,其混剂的风险性高;嘧菌酯和低风险药剂混用,其混剂的风险性会低于嘧菌酯。因此,在大田释放赤眼蜂防治玉米螟等害虫时,应避免高风险杀菌剂的使用,以避免对赤眼蜂的伤害。     

几种新农药防治西瓜枯萎病试验

经两年（1994～1995）多点试验表明，50％菌杀清可湿性粉剂防治西瓜枯萎病效果最佳，防治效果一般可达到80～100％；其次为西瓜重荐剂1号悬浮剂，防治效果可达到80～90％，再次为西瓜重荐剂可湿性粉剂，防治效果一般可达到70～80％；60％百菌通防治效果一般为60％左右。     

桧木醇对西瓜枯萎病菌的抑制作用

由尖孢镰刀菌西瓜专化型(Fusarium oxysporum f. sp. niveum,FON)引起的西瓜枯萎病是一种毁灭性的土传病害。本研究通过离体及活体试验，测定了植物源天然抑菌活性物质桧木醇对西瓜枯萎病菌的抑制活性、对西瓜枯萎病的盆栽防效以及对病原菌生理生化指标的影响。结果表明：桧木醇对西瓜枯萎病菌具有明显的抑制效果，其对病原菌菌丝生长和孢子萌发的抑制作用EC₅₀值分别为31.1和45.2μg/mL；在250、500和1000μg/mL 3个质量浓度下，桧木醇对西瓜枯萎病均有显著的防治效果，其中1000μg/mL时防效可达75.2%，与对照药剂多菌灵500μg/mL的效果相当。生理生化指标测定及外观形态观察发现，经桧木醇处理后，西瓜枯萎病菌菌丝相对电导率上升，菌丝体内镰刀菌酸含量显著降低，菌丝呈现扭曲、畸形、缠绕等不规则外观形态。研究表明，桧木醇不仅能显著抑制西瓜枯萎病菌的生长，同时能抑制其相关毒素的生物合成或促进其代谢，从而降低病原菌的致病力，具有开发为西瓜枯萎病防治替代药剂的潜力。桧木醇处理能破坏病原菌细胞膜的完整性、干扰病原菌次生代谢物的合成或代谢过...     

苯醚甲环唑和吡唑醚菌酯混合物对炭疽病菌的联合毒力及药效

为了明确苯醚甲环唑与吡唑醚菌酯混合物对胶孢炭疽菌（Colletotrichum gloeosporioides）的毒力增效作用,本文采用菌丝生长速率法测定了苯醚甲环唑、吡唑醚菌酯及其不同比例混合物对炭疽病菌的毒力,并通过田间试验评价了其对炭疽病的防治效果和产量的影响。结果表明：苯醚甲环唑与吡唑醚菌酯质量比为2∶1的混合物对抑制菌丝生长增效最为明显,增效系数为2.41。在田间药效试验中,2种药剂2∶1混用对祁山药炭疽病的防效明显,增产率为45.02%。     

西瓜枯萎病菌对西瓜种子发芽和幼苗生长发育的影响

分别采用滤纸法和浸胚根法测定了西瓜枯萎病菌对西瓜种子发芽和幼苗生长发育的影响。结果表明,枯萎病菌孢子悬浮液浓度为106～107个/ml时,种子的发芽势和发芽率均显著低于对照,并且对京欣1号品种和航兴1号品种种子发芽的影响大于黄小帅;枯萎病菌孢子悬浮液处理种子后,幼苗的茎长、子叶长度、子叶宽度、第3叶长度、第3叶宽度、百株鲜重等指标均有所降低,当浓度为106～107个/ml时,除百株鲜重和航兴1号品种幼苗的第3叶长度外,与对照相比,其他指标均显著降低。     

Rootstock resistance to Fusarium wilt and effect on watermelon fruit yield and quality

The potential of grafted watermelon for resistance toFusarium oxysporum f.sp.niveum on some Curcurbitaceae,Lagenaria, Luffa, Benincasa and commercial rootstocks was evaluated. Effects of grafting on yield and quality of diseased plants were evaluated. All grafted plants and rootstocks were resistant to the three known races (0, 1, and 2) ofF. oxysporum f.sp.niveum except watermelon cv. ‘Crimson Tide’, which was susceptible to race 2. Fruit yield was positively (21–112%) affected byLagenaria rootstocks but negatively affected (200–267%) byCucurbita rootstocks when compared with the control. While only minor differences in fruit quality were determined in control and grafted plants onLagenaria rootstocks, the quality parameters for watermelon grafted ontoCucurbita rootstocks were lower than in the control. The reasons for low yield and quality might be due to an incompatibility betweenCucurbita rootstocks and watermelon. These results showed that rootstock influence on disease resistance as well as yield and quality of scion fruit is important in determining the potential use of grafting applications in watermelon. http://www.phytoparasitica.org posting Feb. 2, 2003.     

西瓜上检疫性有害生物

按照FAO的国际植物检疫措施标准第2号——有害生物风险分析准则，对进境西瓜进行有害生物风险分析。最终提出15种检疫性有害生物，其中在我国已局部分布的有甜瓜枯萎病菌、甜瓜球腔菌、黄瓜绿斑驳病毒、西瓜细菌性果斑病、条纹瓜叶甲、甜瓜绢叶螟；在我国尚未见报道的有果实蝇属、西瓜船象、寡鬃实蝇和甜瓜坏死斑病毒。本文对其分布、寄主和危害特性作一简要阐述。     

土壤施加氧化钙对西瓜枯萎病的影响及其机理初探

为探明土壤撒施石灰对西瓜枯萎病发生的影响,本试验设计5个浓度剂量的氧化钙对连作西瓜5年的土壤进行消毒处理,通过栽培感病品种并调查植株生长情况、枯萎病发病率等指标,结合土壤中尖孢镰刀菌西瓜专化型1号小种病原菌孢子量和土壤pH的变化动态,以此评估土壤施加石灰防治西瓜枯萎病的效果,并利用不同浓度的钙对尖孢镰刀菌西瓜专化型菌丝生长和产孢量的影响进行防治机理的初步研究。试验结果表明,当土壤施加氧化钙后,西瓜发病率显著降低,各处理的相对防效分别为14%、57.8%、96.3%、94.7%、94.7%。在定植10d后,各处理均有促进植株生长发育的作用,其中1.34g/kg最显著。而随着氧化钙施加量的增加,土壤pH值也不断提高,30d趋于稳定。对土壤病原菌孢子数量检测表明:各处理土壤中病原菌数量均呈现显著降低的趋势。PDA平板生测结果表明,当钙离子浓度高于80mmol/L时,病原菌的生长及产孢量开始受到抑制,随着浓度的增加,抑制作用加强。土壤施加氧化钙不仅能改善土壤的酸化,还能有效防控西瓜枯萎病,其机理可能是土壤pH值的提高改变了土壤微环境,不利于病原菌侵染;施加的钙离子抑制了病原菌菌丝的生长及孢子的萌发。研究结果对揭示氧化钙防控西瓜枯萎病机制,具有一定的参考价值。     

Nitrogen metabolism disorder in watermelon leaf caused by fusaric acid

The effect of fusaric acid (FA) on the activity of leaf nitrogen (N) metabolism enzymes in watermelon seedlings supplied with different N forms was studied. The results showed that FA inhibited nitrogen uptake and caused decreased leaf amide and protein but increased the content of ammonium and amino acids. When treated with FA the activities of enzymes in the pathway for the synthesis of amino acid in leaves (GS, GOGAT, and GDH) were decreased by 15–23%, 13–40%, and 71–86%, respectively. The activity of asparagine synthetase was decreased by 34–57%. The proteinase activity was initially increased by 37–125% at 12 h after treatment of FA but then subsequently decreased. The activity of glutamate-pyruvate aminotransferase was increased by 280–400%, though the activity of glutamate-oxaloacetate aminotransferase was decreased by 30–63%. It was suggested that FA inhibited the uptake of ammonium in seedlings and suppressed the activities of amino acid and amide synthases, while stimulating proteinase activity.A new pathogenic mechanism of watermelon infection by Fusarium spp. was found as FA caused the complete disorder and collapse of the host plant's nitrogen metabolism. This work provides a new insight into the progression of watermelon wilting caused by Fusarium oxysporum f.sp. niveum.     

Companion cropping with wheat increases resistance to Fusarium wilt in watermelon and the roles of root exudates in watermelon root growth

Pot experiments were performed to investigate the effects of companion cropping with D₁₂₅ wheat on Fusarium wilt in watermelon. Fusarium oxysporum f. sp. niveum (Fon) is responsible for Fusarium wilt in watermelon. Also, the relationship between root exudates of wheat and watermelon growth was estimated. Studies showed that companion cropping with D₁₂₅ wheat reduced the incidence rate of watermelon Fusarium wilt. Companion cropping with D₁₂₅ wheat decreased malondialdehyde content and increased activities of phenylalanine ammonia-lyase and polyphenol oxidase and contents of flavonoid, total soluble phenolics and lignin in watermelon roots after inoculation with Fon compared to monoculture. qRT-PCR showed that the expression levels of six specific genes were higher during the early stage of Fon infection in companion cropping than in monoculture. D₁₂₅ wheat root exudates increased root length, root surface area, root volume, root number, root dry weight, but decreased root mean diameter in watermelon seedlings in the absence of sodium orthovanadate. These results suggest that companion cropping with D₁₂₅ wheat reduced Fusarium wilt in watermelon by promoting the growth of watermelon roots and by triggering gene expression and physiological changes to protect the watermelon from injury.     

AM真菌和镰刀菌对西瓜根系膜脂过氧化作用和膜透性的影响

 在温室盆栽条件下研究了丛枝菌根(arbuscular mycorrhiza,AM)真菌Glomus versiforme (Karsten) Berch和西瓜枯萎镰刀菌(Fusarium oxysporum f. sp. niveum)对西瓜根系中膜脂过氧化产物丙二醛(MDA)含量和细胞膜透性的影响。结果表明,接种AM真菌的西瓜根系中MDA含量、组织自动氧化速率和膜透性均低于对照,先接种G. versiforme,后接种F. oxysporum f. sp. niveum处理的MDA含量、组织自动氧化速率和细胞膜透性均低于只接种F. oxysporum f. sp. niveum的处理。接种G. versiforme感枯萎病西瓜品种"郑杂5号"MDA含量、组织自动氧化速率和膜透性降低幅度大于抗病品种"京欣1号"的接种处理,说明G. versiforme可降低感病西瓜品种的膜透性和MDA的产生,从而有效地保护细胞膜系统,减轻F. oxysporum f. sp. niveum对西瓜的为害程度。     

海南岛西瓜病毒病种类鉴定及发生分布

From October 2017 to April 2019, a total of 290 suspected virus-infected watermelon leaf samples were collected in 7 urban areas (Wenchang, Wanning, Lingshui, Sanya, Ledong, Dongfang, Changjiang) in Hainan island. Nine viruses were detected including MYSV, WSMoV, CCYV, CMV, TMV, CGMMV, ZYMV, WMV and PRSV by small RNA deep sequencing and RT-PCR. The detection rates of MYSV, CCYV, CGMMV, ZYMV, CMV, WSMoV, PRSV, TMV and WMV were 66.90%, 25.86%, 22.07%, 17.59%, 10.00%, 7.59%, 5.52%, 2.76% and 1.03% respectively. The co-infection rate of virus was 56.56% and 14 types of mixed infections were detected. The results of this study clarify the identification and distribution of waterme-lon-infecting viruses in Hainan.     

海南岛西瓜病毒病种类鉴定及发生分布

正病毒病是西瓜生产上的重要病害,目前侵染我国西瓜的病毒主要有西瓜花叶病毒(watermelon mosaic virus,WMV)、黄瓜花叶病毒(cucumber mosaic virus,CMV)、黄瓜绿斑驳花叶病毒(cucumber green mottle mosaic virus,CGMMV) 、甜瓜黄斑病毒(melon yellow spot virus,MYSV)、小西葫芦黄花叶病毒