江淮部分地区麦田日本看麦娘对精噁唑禾草灵的抗性及其交互抗性

江淮地区是我国重要的小麦产区之一。为明确该地区麦田日本看麦娘对精噁唑禾草灵的抗性情况,采用整株水平生物测定法检测了该地区的10个种群对精噁唑禾草灵的抗性水平;扩增和比对了高抗种群（AH-40、JS-19）、中抗种群（AH-41、JS-20）与敏感种群（AH-7）的ACCase CT区域基因片段差异,并测定了GSTs、P450s酶抑制剂对精噁唑禾草灵的增效作用及4个抗性种群对8种除草剂的抗性。结果表明,高水平抗性种群数量占供试种群总数的50%,抗性指数为13.14~18.54;测序结果表明,高抗和中抗种群中均未发现已报道可引起靶标抗性的位点突变。AH-40种群在施用GSTs代谢酶抑制剂（灭草环、三聚氯氰、NBD-Cl）和P450s酶抑制剂（PBO、马拉硫磷）后均可显著提高其对精噁唑禾草灵的敏感性,增效倍数分别为1.68、1.68、2.45、1.64、2.03;JS-19种群在施用GSTs酶抑制剂（灭草环、三聚氯氰、NBD-Cl）后GR₅₀有所下降,增效倍数为1.71、1.94、1.71;供试酶抑制剂未对其他抗性种群产生明显增效作用。抗性检测结果显示,4个抗性种群均对炔草酯和甲基二磺隆高抗,AH-41、JS-19高抗高效氟吡甲禾灵,JS-20高抗烯禾啶,但均对唑啉草酯、啶磺草胺、氟唑磺隆和异丙隆敏感。     

山东省小麦田看麦娘对甲基二磺隆的抗性及其基因突变

为明确山东省麦田看麦娘种群对甲基二磺隆的抗性情况及可能存在的抗性机理,本研究在临沂、日照等山东省看麦娘发生严重地区的小麦田共采集10个看麦娘种群,在温室条件下测定了其对甲基二磺隆的抗性以及对其他4种除草剂的敏感性,扩增和比对了靶标酶乙酰乳酸合成酶(acetolactate synthase,ALS)基因部分片段的差异。结果表明,SDTC-4种群对甲基二磺隆具有高抗性,抗性倍数达30.1,其他种群对甲基二磺隆敏感,抗性倍数在1.0~1.8之间。对ALS基因片段测序发现,SDTC-4种群看麦娘ALS基因197位氨基酸由脯氨酸(CCC)突变为丝氨酸(TCC)(P197S),其他种群均未发现有突变产生。SDTC-4种群对啶磺草胺和氟唑磺隆产生了一定的交互抗性,在推荐剂量下死亡率分别为10.0%和13.3%。所有的看麦娘种群对精噁唑禾草灵和异丙隆敏感,推荐剂量下死亡率达100%。本研究是看麦娘对甲基二磺隆抗性在山东省的第一例报道,ALS基因P197S突变是第一次在看麦娘中被发现,该突变很可能是导致SDTC-4种群对甲基二磺隆产生抗性的重要原因之一。     

4种除草剂对小麦田雀麦(Bromus japonicus)的田间药效试验

以北京市大兴区常用冬小麦品种农大211为试验材料,在春季以30 g/L甲基二磺隆、70%氟唑磺隆、10%精噁唑禾草灵和40%三甲苯草酮为试验药剂,对冬小麦麦田杂草雀麦的防治效果进行研究。结果表明:30 g/L甲基二磺隆20 m L/667 m~2、70%氟唑磺隆2 g/667 m~2和10%精噁唑禾草灵水乳剂10 g/667 m~2在药后28 d鲜质量防效达到了90%以上,防治后小麦与对照相比分别增产35.82%、33.69%和59.57%,对千粒质量影响差异显著(P0.05),对穗粒数没有影响。本次试验中40%三甲苯草酮水分散粒剂40 g/667 m~2防治雀麦与对照相比效果不明显。     

水稻田糠稷种子萌发和出苗特性及化学防除药剂筛选

【目的】糠稷已成为我国局部水稻田主要恶性杂草之一。明确糠稷的种子萌发和出苗特性,探索化学防除技术具有重要意义。【方法】通过室内及温室试验,测定了温度、光照、盐和渗透胁迫、水层深度、土层深度对糠稷种子萌发及出苗的影响,并评估了水稻田常用苗前封闭和苗后茎叶除草剂对糠稷的防效。【结果】1）糠稷种子在20/10℃(昼/夜)～35/25℃温度范围萌发率均大于95%,且光照/黑暗交替处理的萌发率大于持续黑暗处理。糠稷萌发率随水势降低而下降,-0.35 MPa的水势对其种子萌发的抑制率达50%。250 mmol/L NaCl处理后糠稷萌发率大于50%,表明其耐盐胁迫能力较强。2）糠稷仅能在0～0.5cm土层深度萌发出苗,播种深度大于0.5cm时未见其出苗。水层大于2 cm时糠稷幼苗无法长出水面。3）在田间推荐剂量下,丙草胺、丁草胺、噁草酮、丙炔噁草酮和双唑草腈苗前土壤喷雾对糠稷防效100%,氯氟吡啶酯、五氟磺草胺、双草醚、氰氟草酯、噁唑酰草胺和精噁唑禾草灵可防除95%以上2～4叶期糠稷,在糠稷6叶期时选用噁唑酰草胺和精噁唑禾草灵,防治效果亦可达到90%以上。【结论】明确了环境因子对糠稷种子萌发和出苗...     

除草剂混配施用对棉田常见杂草的防除效果

为了检验除草剂防除棉田杂草效果,以三氟啶磺隆、嘧草硫醚和精喹禾灵之间不同剂量的混配施用.试验表明：三氟啶磺隆和精喹禾灵两种混用及三氟啶磺隆、嘧草硫醚和精喹禾灵3种混用均对棉田杂草都有较好的防除效果.施药后7天杂草表现药害症状.施药后20天,三氟啶磺隆与精喹禾灵两种除草剂混用,随着三氟啶磺隆用量的增加对禾本科杂草的防效由89.2％增加到95.3％,对阔叶类杂草的防效由86.3％增加到94.9％,总体株防效由87.8％增加到95.2％;三氟啶磺隆与精喹禾灵、嘧草硫醚混剂3种除草剂混用,在精喹禾灵用量相同的条件下,增加三氟啶磺隆或嘧草硫醚的用量,对禾本科杂草、阔叶类杂草、杂草总体株防效均提高.施药后40天的株防效和鲜重防效均80％以上,说明混配药剂的持效期较长.     

不同药剂对麦田田埂杂草蛇床和灰绿藜的防除效果

田埂杂草对农业生产会产生不利影响,为安全有效解除其影响,试验不同除草剂对蛇床[Cnidium monnieri (L.) Cuss.]和灰绿藜(Chenopodium glaucum L.)的防除效果。结果表明,50%丙草胺SC 80 m L/667 m2+7.5%精噁唑禾草灵SC 100 m L/667 m2+20%双氟·氟氯酯WG 6 g/667 m2效果最好,对蛇床和灰绿藜的校正株防效分别高达93.1%、94.3%;鲜质量防效分别达到99.1%、98.7%。     

棉田外来入侵杂草黄顶菊的化学防除

 研究了棉田7种土壤除草剂和7种茎叶除草剂对黄顶菊的防效。结果表明：土壤除草剂室内生测以48%仲丁灵EC 200～400倍防效最佳,90%乙草胺EC 200～400倍、50%敌草胺WP 133～400倍也表现出较高防效。田间土壤处理以96%精异丙甲草胺EC 720.0～1440.0 g·hm^-2处理防效最佳,48%氟乐灵EC、90%乙草胺EC、50%扑草净WP也表现出较高防效。茎叶除草剂田间试验以25%氟磺胺草醚AS 281.5～563.1 g·hm^-2防效最佳,20%百草枯AS中高浓度、75%三氟啶磺隆钠盐WP、75%嘧硫草醚WP和41%草甘膦AS也具有较高防效。     

播娘蒿对双氟磺草胺的抗性水平及靶标抗性分子机理

为明确麦田杂草播娘蒿对双氟磺草胺的抗性水平及靶标抗性分子机理,采用整株-剂量响应法测定了播娘蒿对双氟磺草胺的抗性水平,通过克隆测序进行了靶标乙酰乳酸合成酶(ALS)基因序列比对分析,并通过测定靶标酶离体活性,分析了抗性和敏感种群播娘蒿ALS对双氟磺草胺的敏感性。结果显示,与敏感种群TS 相比,抗性种群G₁₃₀ 对双氟磺草胺产生了高水平抗性,抗药性指数为108.6;在G₁₃₀种群中随机抽取100株,对其ALS基因进行测序,比对分析发现,33%植株ALS 的第197位脯氨酸突变为苏氨酸,40%植株ALS 的第574位色氨酸突变为亮氨酸,27%植株的ALS 同时存在上述两种突变。ALS 离体活性测定结果表明,双氟磺草胺对抗性种群ALS 的活性抑制中浓度为敏感种群的137.8倍。这说明,播娘蒿抗性种群ALS 关键位点氨基酸的突变可能是导致其对双氟磺草胺产生高水平抗性的重要原因之一。     

4种除草剂对夏玉米田杂草及麦苗的防效与安全性比较

选用4种莠去津复配剂进行玉米田杂草防除效果及安全性研究,筛选对夏玉米田杂草及自生麦苗的防效及安全性较好的除草剂。结果表明,31.5%噻酮磺隆·异噁唑草酮+38%莠去津总杂草株防效为88.7%,鲜质量防效为98.48%,防效较好,无明显药害症状,且玉米产量为各药剂处理中最高;22%烟嘧·莠去津和30%苯唑草酮+助剂+38%莠去津对自生麦苗株防效均在80%以上,鲜质量防效在95%以上;30%苯唑草酮+助剂+38%莠去津对莎草的株防效仅45.58%,莎草为主的夏玉米田块尽量不使用。     

10%氰氟·精噁唑EC防除水稻直播田千金子的效果研究

为给水稻直播田草害的化学防控提供依据,通过2年田间试验研究了10%氰氟.精噁唑EC（乳油）对水稻直播田千金子的控制效果和应用安全性。结果表明,氰氟.精噁唑对直播稻田6~7叶期的千金子具有良好的防除效果,有效成分用量75~90 g/hm2药后10 d的密度防效可达85%,药后20 d的密度防效可达90%以上、鲜重防效可达98%;相同用药量的密度防效显著优于对照药剂氰氟草酯。施用氰氟.精噁唑能显著提高水稻产量,增产效果达19.18%～27.41%。氰氟.精噁唑可作为水稻直播田防除大龄千金子的优良备选药剂。     

Characterisation and management of Phalaris paradoxa resistant to ACCase-inhibitors

Phalaris paradoxa is a competitive grass commonly found in durum wheat crops of central and southern Italy. Among the 85 populations screened from 1998 to 2008 for resistance to ACCase-inhibitors and graminicide sulfonylureas, 17 resulted as being resistant to at least one ACCase inhibitor while none of the populations showed resistance to sulfonylureas. ACCase resistance in hood canary-grass seems to be spreading rather slowly in Italy. Out of the 17 populations, seven were characterised through outdoor dose-response pot experiments to investigate resistance levels and cross-resistance patterns to ACCase-inhibitors and multiple resistance to other mode of action. Molecular bases of resistance to the recently introduced DEN herbicide pinoxaden were also investigated. Six populations were confirmed to be ACCase-resistant with various cross-resistance patterns. Two populations were resistant to all tested ACCase herbicides, with pinoxaden resistance indexes (RI) based on survival ranging from 22 to 50. The two populations have been molecularly characterised for resistance to pinoxaden. A single point-mutation in the ACCase gene was identified in each population, causing the amino-acid substitutions of Ile₁₇₈₁Val and Asp₂₀₇₈Gly in 0478L and 0025, respectively. The results suggest that resistance of P. paradoxa to pinoxaden is due to an altered target site and different mutations cause different resistance levels. The biological characteristics of the species, mainly self-pollinated, and the absence of multiple resistance allow herbicides with different modes of action to be used for controlling ACCase-resistant populations. Chemical tools should be carefully used within integrated weed management strategies.     

Wild tuber-bearing species ofSolanum and incidence ofPhytophthora infestans (Mont.) de Bary on the Western slopes of the volcano Nevado de Toluca. 5. Type of resistance toP. infestans

Summary Plants of wildSolanum species (S. demissum (dms), S. verrucosum (ver), S. iopetalum (iop), S. brachycarpum (bra), and an unidentified species (unsp), from the natural habitat were inoculated in the laboratory withPhytophthora infestans race 0, to see if major genes for resistance were present, and with the most complex and aggressive race available in an attempt to reveal the level of general resistance. No plant with a susceptible reaction to race 0 was found in 120 plants ofdms, and 34 plants ofunsp. Plants with a hypersensitive reaction to race 0 and susceptible plants were found inver. When infected with a complex aggressive isolate of the fungus 73.5% of the WSS plants were susceptible. It was concluded that WSS in the area possess both complex race specific resistance and a high level of general resistance, whose effects cannot yet be separated.     

Evaluation of diploid potato clones for resistance to tuber soft rot induced by strains ofErwinia carotovora subsp.atroseptica,E. carotovora subsp.carotovora andE. chrysanthemi

Summary Tubers of clones from a diploid hybrid population ofSolanum phureja andS. stenotomum were screened for resistance to tuber soft rot caused by strains ofErwinia carotovora subsp.atroseptica (Eca),E. carotovora subsp.carotovora (Ecc) andE. chrysanthemi (Ech). Significant, positive correlations between resistance to the different strains and species were observed, indicating that screening for resistance to tuber soft rot could be accomplished by using just one of the three pathogens. Strains of Ecc and Ech were found to be much more virulent than strains of Eca. Inoculating with Ecc and Ech resulted in more distinct differences among susceptible, moderately resistant and resistant clones than inoculating with Eca.     

Detecting ALS and ACCase herbicide tolerant accession of Echinochloa oryzoides (Ard.) Fritsch. in rice (Oryza sativa L.) fields

Inconsistent control of Echinochloa oryzoides has been reported repeatedly by farmers in the major rice growing area of Turkey. Greenhouse studies confirmed the existence of cross and multiple herbicide tolerance of E. oryzoides accessions including acetolactate synthase (penoxsulam, bispyribac-sodium) and acetyl CoA carboxylase (cyhalofob-butyl) inhibiting herbicides. Comparison of 95% lower confidence intervals of ED₉₀ derived from log-logistic dose–response curves, and twice the recommended field rates of the herbicides showed some, but not distinct separation of susceptible and tolerant accessions. We used a novel method to separate heterogeneous data without a priori knowledge of grouping into more than one group. On the basis of the distribution of ED₉₀ it was possible to identify two distinct groups of the 172 accessions tested, 78% were not controlled by ALS inhibitors (penoxsulam, and bispyribac-sodium) at recommended field rates; and 38% were not controlled by the ACCase Inhibitor (cyhalofob-butyl) at twice the field rates. The effective response level of ED₉₀ resulted in 64 and 14 tolerant accessions to ALS and ACCase, respectively. Fourteen accessions showed multiple resistances to ALS and ACCase Inhibitors.Some of the accessions were strongly tolerant to both herbicide modes of action and had 100% survival even at 6 times the recommended rates. Most of these tolerant accessions were from Marmara region, predominantly in Edirne and Balıkesir, which are the regions without any crop rotation.     

不同玉米品种抗蚜性室内鉴定

采用环境气候室人工接蚜虫鉴定和累计蚜情指数(I_(aa))评判法,对22份玉米品种进行抗玉米蚜Rhopalosiphum maidis Fitch鉴定。结果表明,不同玉米品种的抗蚜性差异显著,在抗性品种上玉米蚜种群数量为负增长,产生的有翅蚜少;在感虫品种上玉米蚜种群数量急剧增长,并伴随大量有翅蚜产生。I_(aa)值从高抗蚜品种的1.1到高感品种的31.4。高感或感蚜品种9个,占比41%;中抗和抗蚜品种4个,占比18%;高抗品种9个,占比41%。生产上推广种植面积较大的京科968和先玉335等具有中等抗蚜水平,郑单958等高感蚜虫。     

Susceptibility variation to new and established herbicides: Examples of inter-population sensitivity of grass weeds

The objectives of this study were to describe the intra-specific variation in herbicide response of weed populations when subjected to new vs. well-established herbicides, and to assess distributions of logLD₅₀- and logGR₅₀-estimates as a potential indicator for early resistance detection. Seeds of two grass weeds (Alopecurus myosuroides, Apera spica-venti) were collected in southern Sweden, mainly in 2002. In line with the objectives of the study, the collections sites were not chosen for noted herbicide failures nor for detected herbicide resistance, but solely for the presence of the target species. For each species, seedlings were subjected to two herbicides in dose-response experiments in a greenhouse. One herbicide per species was recently introduced and the other had been on the market for control of the species for a decade, with several reports of resistance in the literature. Fresh weight of plants and a visual vigour score were used to estimate GR₅₀ and LD₅₀, respectively. Resistance to fenoxaprop-P-ethyl in A. myosuroides was indicated by the LD₅₀-estimates to be present in frequencies sufficient to affect the population-level response in 9 of 29 samples, and was correlated to response to flupyrsulfuron, while low susceptibility to isoproturon in A. spica-venti populations was not linked to the response to sulfosulfuron. In the study as a whole, the magnitude of the estimated herbicide susceptibility ranges differed irrespective of previous exposure. No consistent differences were found in the distribution of LD₅₀-estimates for new and “old” herbicides, and normality in the distribution of estimates could not be assumed for a non-exposed sample, even in the absence of an indication of cross-resistance.     

Selection,mechanism, cross resistance and stability of spinosad resistance in Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae)

Spodoptera litura is one of the most destructive pests in Pakistan and in many other regions of the world. A field collected population of S. litura was selected with spinosad for eleven generations under controlled laboratory conditions to study the cross resistance, mechanism and stability of spinosad resistance in S. litura. The resistance to spinosad in S. litura increased 3921-fold (after eleven generations of selection with spinosad) as compared to a susceptible population of S. litura. No cross resistance between spinosad and emamectin benzoate, methoxyfenozide, fipronil, indoxacarb, profenofos, lufenuron or deltamethrin was found in the spinosad-selected population of S. litura. To find the possible mechanism of spinosad resistance in S. litura two synergists, Piperonyl butoxide (PBO), S, S, S-tributyl phosphorotrithioate (DEF) were tested on the susceptible and resistant strains and on the un-selected field population. The values of the synergism ratios of PBO and DEF were 2.33 and 1.06 for the spinosad-selected strain, 1.36 and 1.06 for the un-selected field population and 1.14 and 1.00 for the susceptible strain, respectively. As high PBO ratio indicates the role of microsomal O-demethylase in causing spinosad resistance in S. litura. The spinosad-resistant and field populations of S. litura were reared without any selection pressure from the 12th to the 16th generation (G₁₂–G₁₆). The spinosad resistance decreased from 3921 to 678-fold in the spinosad-resistant population and from 31.1 to 15.1-fold in the un-selected population of S. litura as compared to the susceptible strain. Spinosad resistance in S. litura has a high reversion rate (−0.15) which indicates that spinosad resistance in S. litura is unstable and can be easily managed by switching off the selection pressure for a few generations or alternating with insecticides having different modes of action.