三环唑和嘧菌酯在水稻植株和田间的残留及消解动态

【目的】研究三环唑和嘧菌酯在水稻植株、稻田水和土壤中的残留及消解动态。【方法】水稻样品用乙腈或二氯甲烷提取,提取液浓缩后经高效液相色谱(三环唑)和气相色谱(嘧菌酯)分析。【结果】三环唑和嘧菌酯的最低检出限(LOQ)分别为0.05和0.01 mg·L~(-1),平均回收率分别为78.5%~100.8%和73.9%~109.7%,相对标准偏差(RSD)分别为1.0%~12.9%和3.1%~12.9%;三环唑和嘧菌酯在水稻植株、稻田水和土壤中的残留消解动态规律符合一级动力学方程,三环唑和嘧菌酯的半衰期分别为2.4~13.1和4.3~16.1 d。【结论】三环唑和嘧菌酯属于易降解农药,检测方法的灵敏度、准确度及精密度均符合农药残留分析要求。     

种子包衣用耐水成膜剂ZY904的应用效果

本试验通过对耐水成膜助剂ZY904-1、ZY904-2、ZY904-3的物理化学性能和应用性能指标的测定来评价成膜剂性能,从而探究成膜剂在水稻种子包衣上的应用效果,筛选出能显著提高农药缓释性能的成膜剂及添加浓度。试验通过高效液相色谱法,定量测定了浸种后不同时间点农药保持率。结果表明：成膜剂ZY904-2在添加浓度为0.5%时,包衣均匀度达95.7%,包衣脱落率为1.7%,与对照相比,发芽势和发芽率增长率为1.25%、3.23%,株高和根长提高0.52、0.62 cm,地上干重和地下干重增重0.46、0.33 g,在浸水40天后,嘧菌酯保持率仍能达到47.26%。成膜剂ZY904-2在应用于水稻种衣剂后能促进植株生长,显著提高嘧菌酯缓释性能,推荐应用于水稻种衣剂研究开发中。     

嘧菌酯250g/L悬浮剂的研制

本研究采用流点法和Zeta电势对嘧菌酯悬浮剂的润湿分散剂进行筛选,利用黏度法确定了润湿分散剂的最佳用量;在此基础上,结合嘧菌酯悬浮剂热贮(54±2.0)℃14d后平均粒径变化、悬浮率、黏度等物化性能,确定了嘧菌酯250g/L悬浮剂的最佳配方,结果表明,该产品热贮14d后,悬浮率93%以上,分解率5%,三倍硬水悬浮率≥85%,其他各项指标均符合悬浮剂的要求。     

烟草赤星病菌对嘧菌酯抗性突变体的诱导及其生物学特性

为评价烟草赤星病致病菌链格孢Alternaria alternata对嘧菌酯的抗性风险,以敏感菌株J6为试材,通过菌丝药剂驯化和分生孢子紫外诱变诱导抗性突变体,并对抗性突变体的生物学特性进行了研究,同时对抗性突变体与敏感菌株线粒体的细胞色素b基因 (cyt b) cDNA序列全长进行了测序分析。结果表明:经药剂驯化未获得抗性突变体,而紫外诱变共获得7株抗性突变体,突变频率约为0.007%,抗性水平分别为5.27、8.28、25.28、12.82、6.14、9.28和52.91倍。适合度研究表明,抗性突变体与敏感菌株的分生孢子萌发能力及致病力相当,但分生孢子产生量均高于敏感菌株,菌丝生长速率除突变体6-1外均快于敏感菌株。cyt b基因cDNA序列分析表明:有4株抗性突变体在不同位点上发生了核苷酸突变,其中突变体6-7 cyt b的249位和871位碱基由T突变为C,但其编码的氨基酸未发生突变;突变体6-8 cyt b的734位碱基由T突变为C,引起所编码的245位丙氨酸突变为缬氨酸 (V245A);突变体6-9 cyt b的510位碱基由T突变为A,所编码的170位由精氨酸替代了丝氨酸 (S170R);突变体6-11 cyt b的732位碱基由T突变为A,所编码的244位由苯丙氨酸替代了亮氨酸 (L244F),其776位碱基由T突变为C,所编码的259位由丙氨酸替代了缬氨酸（V259A）,其1 156位碱基由A突变为G,所编码的氨基酸未发生变化。研究结果初步表明,烟草赤星病菌对嘧菌酯存在潜在的抗药性风险,其cyt b基因的点突变与其对嘧菌酯的抗药性有关。     

Pyraclostrobin reduces germ tube growth of QoI‐resistant Mycosphaerella graminicola pycnidiospores and the severity of septoria tritici blotch on winter wheat

The effect of the quinone outside inhibitors (QoI) azoxystrobin and pyraclostrobin on yields of winter wheat where QoI resistant Mycosphaerella graminicola isolates were dominant was investigated in field trials in 2006 and 2007. Pyraclostrobin significantly increased yields by 1·57 t ha^?1 in 2006 and 0·89 t ha^?1 in 2007 when compared to the untreated controls, while azoxystrobin only provided a significant increase of 1·28 t ha^?1 in 2006. These yield increases were associated with reduction in septoria tritici blotch (STB) development as determined by weekly disease assessments over a 7 week interval. The effect of pyraclostrobin on STB was studied in controlled environment experiments using wheat seedlings inoculated with individual M. graminicola isolates. Pyraclostrobin significantly reduced STB symptoms by up to 62%, whether applied 48 h pre‐ or post‐ inoculation with resistant M. graminicola isolates containing the cytochrome b mutation G143A. Extremely limited disease (<1%) was observed on similarly treated seedlings inoculated with an intermediately resistant isolate containing the cytochrome b mutation F129L, while no disease was observed on seedlings inoculated with a wild‐type isolate. Germination studies of pycnidiospores of M. graminicola on water agar amended with azoxystrobin or pyraclostrobin showed that neither fungicide inhibited germination of spores of resistant isolates containing the mutation G143A. However, pyraclostrobin significantly reduced germ tube length by up to 46% when compared with the untreated controls. Although the QoIs can no longer be relied upon to provide effective M. graminicola control, this study provides an insight into why QoIs still provide limited STB disease control and yield increases even in situations of high QoI resistance.     

In vitro effects of flutriafol and azoxystrobin on Beauvaria bassiana and its efficacy against Tetranychus urticae

BACKGROUND: Testing the compatibility of chemical pesticides and fungal biocontrol agents is necessary if these two agents are to be applied together in the integrated management of plant pests and diseases. In this study, the fungicides azoxystrobin (a strobilurin) and flutriafol (a triazole) were tested in vitro for their effects on germination of conidia and mycelial growth of Beauveria bassiana (Bals.) Vuill. and in bioassay for their effect on fungal activity against Tetranychus urticae Koch. The fungicides were tested at three different concentrations [recommended rate for field use (1 × X) and the dilutions 10^?1× X and 10^?2× X]. RESULTS: Flutriafol inhibited growth of mycelia and germination of the fungal conidia at all concentrations tested in vitro, and also reduced the efficacy of B. bassiana in bioassays against mites. The inhibitive effect of azoxystrobin in vitro varied with the concentration applied. A significant effect was observed at 1 × X and 10^?1× X concentrations on both the germination of conidia and mycelia growth. At 10^?2× X concentration, azoxystrobin showed little effect on B. bassiana. However, when this fungicide was tested in bioassays, none of the concentrations reduced B. bassiana activity against mites. CONCLUSION: Azoxystrobin was most compatible with B. bassiana, while flutriafol was the most harmful. Further studies are required to confirm the negative effect of flutriafol on B. bassiana activity. Copyright © 2010 Society of Chemical Industry     

气相色谱法测定嘧菌酯在黄瓜和土壤中的残留方法研究

报道了嘧菌酯在黄瓜及土壤中的残留分析方法。样品用丙酮提取,二氯甲烷萃取,硅胶和酸洗活性碳混合柱净化,用二氯甲烷：乙酸乙酯混合液（7∶3,V/V）淋洗,GC—FTD检测嘧菌酯的残留量。最小检出量为6.25×10-11g,最小检出浓度：黄瓜为0.00125mg·kg-1,土壤为0.00283mg·kg-1。当添加浓度在0.01～1mg·kg-1时,其回收率：黄瓜在89.26%～95.69%之间,土壤在86.65%～101.68%之间。     

应用高分辨质谱法的马铃薯种植土壤嘧菌酯残留快速筛查方法

研究了应用高分辨质谱法的马铃薯种植土壤嘧菌酯残留快速筛查方法,获得土壤中嘧菌酯较为精确的残留结果,对马铃薯种植具有一定参考价值。取经过嘧菌酯悬浮液施药的土壤样品,使用丙酮提取样品,通过硅镁型吸附剂层析实现净化,设定色谱条件与质谱条件,切换正、负离子,定性并定量快速筛查土壤样品中的嘧菌酯残留情况,最终分析不同浓度嘧菌酯与施药时间对残留情况的影响。经试验分析,嘧菌酯在0.02～0.51 mg/L浓度范围呈现高线性关系且相关系数为0.998 7,线性范围在0.49～49.00μg/L,定量下限为0.9μg/L,加标水平差异下回收率为105%～107%,相对偏差为1.8～3.8。同时经分析发现,嘧菌酯浓度越高,消解率越低,因此实际种植时需要适当调整嘧菌酯浓度。     

甲氧丙烯酸酯类杀菌剂的环境降解特性研究

为了掌握甲氧丙烯酸酯类（Strobilurins）杀菌剂在环境中的行为归趋,评价其在环境中的风险性,采用室内模拟实验法,对嘧菌酯、氰烯菌酯和醚菌酯3种Strobilurins杀菌剂在不同温度、pH水体中,不同类型土壤中及氙灯光照环境下的降解特性展开实验。结果表明：在25 ℃, pH5.0、7.0、9.0条件下嘧菌酯和氰烯菌酯水解缓慢,醚菌酯则较快,降解半衰期范围为0.105 d至1 a以上,其水解特性差异与水体pH值和农药本身结构相关;50 ℃时3种Strobilurins杀菌剂水中降解较25 ℃时水解速