LC—MS/MS法测定粮谷中除草剂氯氨吡啶酸及氨氯吡啶酸残留量

建立了高效液相色谱串联质谱法(LC-MS/MS)测定粮谷中除草剂氨氯吡啶酸和氯氨吡啶酸残留量的方法。样品经改进的QuEChERS方法一步完成萃取净化,经酸化乙腈萃取,伯仲胺(PSA)和C18吸附剂填料净化离心后,直接过膜上机检测,萃取和净化的效果可以满足检测要求。LC-MS/MS方法采用Eclipse Plus C18(50 mm 2. 1 mm id,1. 8μm)色谱柱,柱温30℃,流动相为甲醇和乙酸铵/水,梯度洗脱,流速0. 3mL/min,电喷雾电离源正离子(ESI+)多反应监测(MRM)模式检测,采用外标法进行定量。氨氯吡啶酸和氯氨吡啶酸在0. 005～0. 100 mg/L范围内线性关系良好,相关系数为0. 999 7～0. 999 9。在0. 010、0. 020、0. 10 mg/kg水平下的平均加标回收率为71. 7%～105. 5%,相对标准偏差为2. 0%～11. 4%,方法的测定低限为0. 010mg/kg。     

高效液相色谱-串联质谱法测定小麦和土壤中氨氯吡啶酸的残留量

建立了小麦植株、麦粒、面粉、麦麸和土壤样品中氨氯吡啶酸的高效液相色谱-串联质谱(HPLC-MS/MS)检测方法。样品用丙酮提取,经N-丙基乙二胺(primary secondary amine,PSA)串联石墨化炭黑柱净化,以Agilent ZORBAX SB-C18 色谱柱分离,以电喷雾电离串联质谱正离子多反应监测(multiple reaction monitoring,MRM)模式进行测定。结果表明: 在0.01、0.1、0.5、1 mg/kg 4个添加水平下,氨氯吡啶酸在小麦植株、麦粒、面粉、麦麸和土壤中的平均回收率在78.9%~97.9%之间,相对标准偏差在3.6%~9.6%之间。该方法样品前处理简单、快速、分析时间短,灵敏度、准确度和精密度均符合农药残留检测要求,适用于小麦和土壤中氨氯吡啶酸残留的检测。     

碱解法—液质联用测定小麦中2甲4氯异辛酯及其代谢物2甲4氯

本研究采用QuECHERS及碱解衍生技术，结合高效液相色谱-串联质谱法(HPLC-MS/MS)建立了测定小麦籽粒和秸秆中的2甲4氯异辛酯和其代谢产物2甲4氯及其共轭物的残留量的检测方法。籽粒和秸秆样品经0.1%甲酸乙腈提取，0.25 mol/L的氢氧化钠溶液碱解，1 mol/L盐酸酸化，上清液经固相萃取剂净化后，HPLC-MS/MS上机检测。结果显示2甲4氯异辛酯在籽粒和秸秆添加浓度0.02～5 mg/kg的范围内，回收率范围为86%～96%,相对标准偏差为2.1%～5.6%,2甲4氯在籽粒和秸秆添加浓度0.02～5 mg/kg的范围内，回收率范围为94%～106%,相对标准偏差范围为3.0%～6.3%,籽粒和秸秆的方法定量限均为0.02 mg/kg。该方法试剂和材料易得，操作过程简单快捷，回收率及精密度满足农药残留分析要求，可用于实际样品的2甲4氯异辛酯、2甲4氯及其共轭物的残留检测，便于2甲4氯异辛酯在小麦的膳食风险评估。     

QuEChERS-液相色谱-串联质谱法测定模拟稻田环境中水、土壤和水稻植株中二氯喹啉酸残留

采用液相色谱-串联三重四极杆质谱建立了稻田土壤、稻田水和水稻中二氯喹啉酸残留的检测方法。样品经V (甲酸) : V (乙腈) = 2 : 98溶液提取,采用 C₁₈和PSA分散固相萃取净化。以0.1%甲酸水溶液- 甲醇为流动相梯度洗脱,经反相液相色谱柱实现目标化合物的分离。采用电喷雾正离子模式串联质谱法检测,多反应监测模式定性,外标法定量。结果表明:在0.01~1 mg/L范围内,二氯喹啉酸的质量浓度与对应的峰面积间呈良好线性关系 (r ≥ 0.999),方法定量限为 0.0125~0.05 mg/kg。当二氯喹啉酸在水稻土壤和植株中的添加水平为0.05、0.2和1 mg/kg,在田水中的添加水平为0.0125、0.05和0.25 mg/kg时,其平均回收率为85%~112%,相对标准偏差 (RSD, n = 6) 为1.1%~9.3%。采用盆栽模拟试验,于水稻苗期喷施二氯喹啉酸,施药剂量为有效成分375 g/hm2,施药后21 d采样测定结果表明:二氯喹啉酸在水稻植株中消解速率较快,消解率可达94%;而在稻田水和土壤中消解缓慢,消解率分别为33%和45%。本研究建立的方法具有操作简单、灵敏度高、分析时间短和重现性好等优点,适用于稻田土壤、稻田水和水稻植株中二氯喹啉酸残留的检测。     

重金属铅、镉污染下紫茎泽兰对氨氯吡啶酸的耐性

研究了在重金属Pb、Cd污染土壤下,紫茎泽兰对氨氯吡啶酸的耐药性。结果表明,低剂量氨氯吡啶酸处理下,其鲜重防效随Pb浓度的升高显著增加,高剂量则呈先升后降的变化趋势;各处理IC50均小于对照,以500 mg/kg处理时为最低;低剂量氨氯吡啶酸处理时,紫茎泽兰鲜重防效随Cd浓度的增加显著增加,120 g/hm2氨氯吡啶酸处理时则随Cd浓度的增加呈下降趋势,各处理IC50均小于对照,以100 mg/kg处理组为最低;≤ 60 g/hm2氨氯吡啶酸处理时,Pb-Cd复合污染胁迫组的鲜重防效均小于单一Pb、Cd处理组,高于对照,120 g/hm2氨氯吡啶酸处理时,Pb-Cd复合污染胁迫组却高于单一Cd处理组和对照,接近单一Pb处理组,其IC50均高于单一Pb、Cd处理组。证实重金属Pb、Cd污染下,紫茎泽兰对氨氯吡啶酸的耐药性明显下降,鲜重防效显著提高,根系也受到一定程度的抑制,这对我国西南地区尤其是Pb、Cd污染严重地区紫茎泽兰的防治起到积极作用。     

超高效液相色谱-串联质谱法测定百合上的氯虫苯甲酰胺残留

建立超高效液相色谱-串联质谱(UHPLC-MS/MS)快速检测百合中氯虫苯甲酰胺残留的方法。样品经0.1%冰乙酸-乙腈(V/V)提取,乙二胺-N-丙基硅烷(PSA)净化,UHPLC-MS/MS检测,外标法定量。结果表明,在0.005～0.5 mg/L浓度范围内,氯虫苯甲酰胺的质量浓度与色谱峰面积间呈良好的线性关系(R²>0.99);在0.05、0.50、1.00 mg/kg 3个加标水平下,氯虫苯甲酰胺在鲜、干百合的平均回收率为82%～107%之间,相对标准偏差(RSD)在1.87%～7.09%之间,方法定量限(LOQ)为0.05 mg/kg。该方法简便、快捷、灵敏度高等优点,可用于氯虫苯甲酰胺在鲜、干百合中残留检测、定量分析及市场监督抽查等。     

氯虫苯甲酰胺在水稻及稻田环境中的残留动态

采用田间试验方法,研究了氯虫苯甲酰胺在稻田水、土壤和水稻植株中的消解动态,测定了氯虫苯甲酰胺在水稻和土壤中的最终残留量。稻田水和土壤样品采用丙酮提取,水稻样品用乙腈溶液浸泡提取,经玻璃层析柱净化,HPLC紫外分析测定。结果表明,稻田水、土壤、水稻植株、谷壳、糙米中氯虫苯甲酰胺添加浓度为0.005~1.0mg/kg时,平均回收率为85.06%~95.83%,变异系数在2.08%~5.77%之间。方法的最低检测浓度为:稻田水0.005mg/kg,土壤0.01mg/kg,水稻植株0.02mg/kg,谷壳0.02mg/kg,糙米0.01mg/kg。氯虫苯甲酰胺在稻田水、土壤和水稻植株中的消解动态均符合一级动力学方程,半衰期分别为3.1~5.0d、6.6~9.0d、8.0~9.9d。以33.86g/hm2和50.80g/hm2间隔14d施用氯虫苯甲酰胺2次和3次,末次施药21d后氯虫苯甲酰胺的最高残留量为:土壤0.217mg/kg,水稻植株0.879mg/kg,谷壳0.389mg/kg,糙米0.018mg/kg。氯虫苯甲酰胺在糙米中的残留量低于我国和食品法典委员会(CAC)及欧盟的最大残留限量(MRL)标准。     

黄瓜、西瓜和土壤中氯吡脲残留分析方法

建立了黄瓜和西瓜样品中氯吡脲残留的气相色谱检测方法。黄瓜、西瓜瓜瓤和西瓜全瓜中的氯吡脲经丙酮和二氯甲烷混合溶液匀浆提取,土壤样品采用加速溶剂萃取仪(ASE)以丙酮作为提取液进行萃取,浓缩萃取液,并经C18小柱净化、浓缩,正己烷定容后,用GC-ECD测定。结果表明,黄瓜、西瓜瓜瓤和全瓜中氯吡氯的最低检出限均为0.001mg/kg,土壤中的最低检出限为0.002mg/kg。添加水平在0.002～0.5 mg/kg,氯吡脲在黄瓜中的回收率为89.2～106.2%(RSD:6.7～10.3%);在西瓜瓜瓤中的回收率为89.4～99.3%(RSD:4.7～11.0%);在西瓜全瓜中的回收率为92.8～101.0%(RSD:5.7～12.3%);在添加水平为0.01～0.5mg/kg时,氯吡脲在土壤中的回收率为81.4～106.8%(RSD:6.9～12.5%)。该检测方法具有操作简单、灵敏度高、净化效果好等特点,完全能够满足黄瓜和西瓜中氯吡脲残留检测。     

蔬菜和水果中菊酯类农药残留量的检测

用Agilent6890N气相色谱仪摸索建立了蔬菜和水果中的溴氰菊酯、甲氰菊酯、三氟氯氰菊酯、氰戊菊酯等拟除虫菊酯类农药残留量的检测方法。确定了12℃/min为最佳程序升温速率。当样品中的添加浓度为0.05～0.10mg/kg时,添加回收率为85.4%～110.4%。4种菊酯类农药的最低检测浓度为3×10-4～6×10-4mg/kg。     

超高效液相色谱-串联质谱法同时测定玉米及土壤中烟嘧磺隆和2甲4氯残留

采用分散固相萃取法进行样品前处理,建立了超高效液相色谱-电喷雾串联四极杆质谱(UPLC-MS/MS)同时快速检测玉米及其土壤中烟嘧磺隆和2甲4氯残留的方法。样品经乙腈-甲酸[V(乙腈):V(甲酸)=99.9:0.1]提取,C18基质固相分散(DSPE)净化后,采用UPLC-MS/MS、多反应监测模式(MRM)检测,外标法定量。结果显示,烟嘧磺隆和2甲4氯进样质量浓度与峰面积间线性关系良好,在0.005～0.1 mg/kg添加水平范围内,烟嘧磺隆和2甲4氯在不同基质中的平均回收率分别为74.6%～98.0%和81.3%～100.1%,相对标准偏差(RSD)分别为1.1%～3.4%和1.7%～10.5%,定量限(LOQ)均为0.005 mg/kg。     

Dermestid beetles in ‘evolution Canyon’, lower Nahal Oren, Mt. Carmel, including new records for Israel

Fifteen species of dermestid beetles were recorded at ‘Evolution Canyon’ (EC), Lower Nahal Oren, Mt. Carmel, Israel. They represent ~35% of known Israeli dermestid species. The following three species were recorded for the first time in Israel:Trogoderma svriaca Dalla Torre, 1911;Ctesias svriaca Ganglbauer, 1904; andAnthrenus (s.str.) jordaniens Pic, 1934. Adults of 13 species were collected on the more solar radiated, warmer and climatically more fluctuating south-facing slope (SFS); ten species were collected on the opposite, north-facing slope (NFS), which was cooler and climatically more stable. The abundance of adult dermestid beetles was 1.9 times higher on the SFS than on the NFS (86 and 47, respectively). Species richness and abundance distribution at EC (three collecting stations on each slope and one at the valley bottom) were significantly negatively correlated with the plant cover that consisted of trees and bushes (Spearmanr _s ,P=0.007 and 0.039, respectively) and perennials (Spearmanr _s ,P=0.039 and 0.077, respectively), indicating that non-woody plants were preferred by adult dermestid beetles.     

Epidemiology of Toxigenic Fungi and their Associated Mycotoxins for Some Mediterranean Crops

Recent data on the epidemiology of the common mycotoxigenic species of Fusarium, Alternaria, Aspergillus and Penicillium in infected or colonized plants, and in stored or processed plant products from the Mediterranean area are reviewed. Emphasis is placed on the toxigenicity of the causal fungal species and the natural occurrence of well known mycotoxins (aflatoxins, ochratoxins, fumonisins, trichothecenes, zearalenone, patulin, Alternaria-toxins and moniliformin), as well as some more recently described compounds (fusaproliferin, beauvericin) whose toxigenic potential is not yet well understood. Several Fusarium species reported from throughout the Mediterranean area are responsible of the formation of mycotoxins in infected plants and in plant products, including: Fusarium graminearum, F. culmorum, F. cerealis, F. avenaceum, F. sporotrichioides and F. poae, which produce deoxynivalenol, nivalenol, fusarenone, zearalenone, moniliformin, and T-2 toxin derivatives in wheat and other small grains affected by head blight or scab, and in maize affected by red ear rot. Moreover, strains of F. verticillioides, F. proliferatum, and F. subglutinans, that form fumonisins, beauvericin, fusaproliferin, and moniliformin, are commonly associated with maize affected by ear rot. Fumonisins, were also associated with Fusarium crown and root rot of asparagus and Fusarium endosepsis of figs, caused primarily by F. proliferatum. Toxigenic A. alternata strains and associated tenuazonic acid and alternariols were commonly found in black mould of tomato, black rot of olive and citrus, black point of small cereals, and black mould of several vegetables. Toxigenic strains of A. carbonarius and ochratoxin A were often found associated with black rot of grapes, whereas toxigenic strains of A. flavus and/or P. verrucosum, forming aflatoxins and ochratoxin A, respectively, were found in moulded plant products from small cereals, peanuts, figs, pea, oilseed rape, sunflower seeds, sesame seeds, pistachios, and almonds. Finally, toxigenic strains of P. expansum and patulin were frequently found in apple, pear and other fresh fruits affected by blue mould rot, as well as in derived juices and jams.     

Broad bean mottle virus in Morocco; curculionid vectors,and natural occurrence in food legumes other than faba bean (Vicia faba)

Broad bean mottle virus (BBMV) was transmitted from infected to healthy faba-bean plants by the curculionid weevilsApion radiolus Kirby,Hypera variabilis Herbst,Pachytychius strumarius Gyll,Smicronyx cyaneus Gyll, andSitona lineatus L. The latter appeared to be an efficient vector: acquisition and inoculation occurred at the first bite, the rate of transmission was c. 41%, and virus retention lasted for at least seven days.S. lineatus transmitted the virus from faba bean to lentil and pea, but not to the three genotypes of chickpea tested. This is the first report on the generaHypera, Pachytychius, andSmicronyx as virus vectors, and onA. radiolus, H. variabilis, P. strumarius, andS. cyaneus as vectors of BBMV.Out of 351 samples of food legumes with symptoms suggestive of virus infection, 16, 11, 19, and 17% of the samples of chickpea, lentil, pea, and common bean, respectively, were found infected when tested for BBMV in DAS-ELISA. This is the first report on the natural occurrence of BBMV in chickpea, lentil, pea, and common bean. The virus should be regarded as a food-legume virus rather than a faba-bean virus solely, and is considered an actual threat to food legume improvement programmes.     

Characterization of potato potyvirus Y (PVY) isolates from seed potato batches. Situation of the NTN, Wilga and Z isolates

A collection of 38 PVY isolates from seed potato batches, originating from several Western European countries, was characterized by using current biological, serological and molecular tools differentiating PVY strains and groups. The correlation between the three kinds of tests was good but not absolute. No single serological or PCR method was able to discriminate among the five isolate groups found. Twenty-nine isolates belonged to the PVY^N strain and six to the PVY^O strain. No PVY^C was found. Two other isolates reacted serologically like PVY^O, but were unable to elicit a hypersensitive response from the Ny_tbr gene and probably represent the PVY^Z group. At the molecular level, these two isolates showed a combination of both PVY^O and PVY^N and could be recombinants of these strains. Another isolate reacted serologically like PVY^O, but induced vein necrosis in tobacco, like PVY^N-Wilga. Some PVY^N isolates caused tuber ring necrosis in glasshouse conditions. These might belong to the PVY^NTN group. The PVY^NTN, PVY^N-Wilga and PVY^Z groups probably represent pathotypes within strains PVY^N and PVY^O, respectively. The present study also confirms previous reports showing a high genetic variation at the 5 end within the PVYN strain.     

The autumn leafroller: Phenology,damage and parasitoids in a Dutch apple orchard

The phenology of the autumn leafroller,Syndemis musculana, a local pest of apple, was studied in order to forecast larval emergence. From 1983–1986, peak flight as determined with sexpheromone traps was always between 13–18 May. The duration of embryonic development was determined at various constant temperatures and used to estimate the periods of egg hatch in these four years. Each year, most eggs should have hatched in the second decade of June.Differences in attack rates between apple cultivars seem to be explained largely by the variation in picking time. Larvae are only half grown at the beginning of harvest (cv. James Grieve), and have gone into hibernation when the latest variety (cv. Golden Delicious) is picked. Moreover, the varieties Cox's Orange Pippin and Belle de Boskoop, picked about half time, are liable to receive additional damage by caterpillars brought with the picked fruits into storage.Various hymenopterous parasites were reared from caterpillars. As the only leafroller in the orchard which hibernates as mature larva,S. musculana may promote winter survival of some parasitoids, like the eulophidColpyclypeus florus.Samenvatting De fenologie van de herfstbladroller (Syndemis musculana Hübner), een incidentele plaag op appel, werd nader bepaald met het doel het uitkomen van de eieren te kunnen voorspellen. In 1983–1986 viel de piekvlucht, bepaald met behulp van feromoonvallen, steeds tussen 13 en 18 mei.De ontwikkelingsduur van de eieren bij verschillende constante temperaturen werd gebruikt om de periode van uitkomen te schatten. De meeste eieren zullen ieder jaar in de eerste helft van juni uitkomen.Geconstateerde verschillen in schade tussen appelrassen blijken goeddeels terug te voeren op verschillen in pluktijdstip. De rupsen van de herfstbladroller zijn pas half-was als de eerste appels eind augustus geplukt worden, terwijl tegen het einde van de oogst begin oktober de meeste al in winterslaap zijn. Met name tussentijdse rassen, als Cox's Orange Pippin and Schone van Boskoop, lopen extra schade op doordat grotere rupsen met de geplukte vruchten in de kist terecht komen.Uit de rupsen werden negen, al van andere boomgaardbladrollers bekende, sluipwespen gekweekt, Omdat deze bladrollersoort, als enige in de boomgaard, als volgroeide rups overwintert, lijkt zij bij uitstek geschikt als winterwaard.This study was carried out at the Experimental Orchard De Schuilenburg, Schuilenburg 3, 4041 BK Kesteren, the Netherlands, to which address correspondence should be addressed.     

Characterization of Sclerotinia minor populations in Texas peanut fields

In the summer of 2004 an epidemic of sclerotinia blight of peanut, a disease caused by Sclerotinia minor, occurred in Texas in fields where the disease was never previously detected. The disease was observed on many plants within one of the fields (>3000 disease foci), although most foci were <1 m. It is hypothesized that these observations were inconsistent with the recent introduction of a monocyclic pathogen, even if disease developed under conducive environmental conditions. The pattern of disease is most suggestive of the presence of foliar (ascospore) infections, although air temperature was above the known limits for apothecia development if the pathogen had arrived in the field in 2004 peanut seed. To further examine this epidemic, 232 isolates were collected, across a variety of spatial scales spanning this field and other Texas peanut fields, and evaluated for aggressiveness, fungicide sensitivity and genotypic diversity. There was wide variation among isolates for the phenotypic characteristics measured, but there was no evidence that a genotypically unique, highly aggressive, and fungicide resistant isolate had been introduced or evolved. The predominant genotype, TX1, which contained 154 isolates, was found in every county and field population.     

Eyespot of Cereals Revisited: ITS phylogeny Reveals New Species Relationships

Four species so far classified in Pseudocercosporella or Ramulispora (hyphomycetes) are associated with eyespot disease symptoms of cereals. Two of these have been linked to teleomorphs that were described in Tapesia. Sequence data derived from the Internal Transcribed Spacer region (ITS1, 5.8S and ITS2) of the rDNA operon showed, however, that the eyespot fungi associated with Tapesia are not congeneric with Ramulispora sorghi, the type of Ramulispora. The genus name Tapesia is now rejected in favour of the conserved name Mollisia, which appears to comprise heterogeneous fungi. Tapesia yallundae is not closely related to the type of Mollisia, M. cinerea, but clusters separately, being more closely allied to species with Cadophora anamorphs. A new holomorph genus, Oculimacula, is therefore proposed for teleomorphs of the eyespot fungi, while the anamorphs are accommodated in Helgardia gen. nov.     

Transgene herbizidresistente Kulturen

Zusammenfassung Herbizidresistente Kulturpflanzen nehmen unter den derzeit weltweit angebauten gentechnisch veränderten Ackerbaukulturen Sojabohne, Baumwolle, Raps und Mais den weit überwiegenden Anteil ein. Als Ursachen für die rasche Zunahme der Anbauflächen herbizidresistenter Sorten sind unter anderem die Unzulänglichkeiten der für diese Kulturen bestehenden Herbizidlösungen sowie die Zunahme der pfluglosen Bestellverfahren zu sehen. Im Gegenzug hat die Minimalbodenbearbeitung aufgrund der Einführung der Herbizidresistenztechnologie, insbesondere in Sojabohne, ein ausgeprägtes Flächenwachstum erfahren.Als Entscheidungskriterien für die Wahl des Unkrautbekämpfungssystems unter Einbezug des Anbaus herbizidresistenter oder konventioneller Sorten lassen sich aus den Erfahrungen der vergangenen 8 Jahre anführen: Sortenleistung, erhöhte Kulturverträglichkeit und zeitliche Anwendungsflexibilität, Wirkungssicherheit einer Nachauflaufbehandlung in Trockenregionen, Wirkungsbreite, Wirkungsdauer und Bekämpfung resistenter Unkrautbiotypen. Aufgrund fehlender Zulassungen und Kennzeichnungsvorschriften in wichtigen Exportmärkten sind für den Anbau transgener Sorten in Übersee auch Vermarktungseinschränkungen sowie für den Anbau in Europa Haftungs- und Koexistenzregeln wichtige einzelbetriebliche Entscheidungsparameter.Fortschritte erfährt die Herbizidresistenztechnologie kurz- und mittelfristig in der Weiterentwicklung bereits praktizierter Spritzfolgen und Tankmischungen zu Fertigformulierungen der Komplementärherbizide mit residualen Partnern. Zur Bekämpfung und Vorbeugung der Ausbreitung neuer herbizidresistenter Biotypen werden die Komplementärherbizide mit Partnern anderer Wirkungsmechanismen kombiniert. Weitere Entwicklungen sind die Kombination verschiedener transgener Merkmale mit der Herbizidresistenz sowie die Ausweitung von den derzeit dominierenden Kulturen auf weltweit weniger bedeutsame Kulturen, in denen die Entwicklung neuer konventioneller Herbizidwirkstoffe bisher wenig erfolgreich war oder im Verhältnis zum Aufwand nur bedingt attraktiv ist. Für die langfristige Entwicklung könnte die Plastidentransformation zur Verhinderung einer unerwünschten Ausbreitung transgener Merkmale Bedeutung erlangen.     

Pathogenic fungi involved in root rot of peas in the Netherlands and their physiological specialization

Research on root rot pathogens of peas in the Netherlands has confirmed the prevalence ofFusarium solani, F. oxysporum, Pythium spp.,Mycosphaerella pinodes andPhoma medicaginis var.pinodella. Aphanomyces euteiches andThielaviopsis basicola were identified for the first time as pea pathogens in the Netherlands. Other pathogens such asRhizoctonia solani andCylindrocarpon destructans were also found on diseased parts of roots. F. solani existed in different degrees of pathogenicity, and was sometimes highly specific to pea, dwarf bean of field bean, depending on the cropping history of the field.A. euteiches was specific to peas, whereasT. basicola showed some degree of physiological specialization.     

Surveys of cereal diseases and pests in the Netherlands. 3. Monographella nivalis and Fusarium spp. in winter wheat fields and seed lots

Data from surveys of winter wheat fields in the period 1974–1986 and of seed lots in the period 1962–1986 and identifications of diseases on plant samples were compiled to describe the occurrence of snow mould (Monographella nivalis) andFusarium spp. On average,M. nivalis dominated overFusarium spp. The complex ofFusarium spp. constituted mainly ofF. culmorum, followed byF. avenaceum andF. graminearum. M. nivalis was dominant in May on stem-bases and in July on leaves and leaf sheaths. On seedsM. nivalis predominated only in years with low temperatures in July and August.Average brown footrot infection in the field was 4% tillers in May and 5% culms in July. Brown footrot intensity in July was high in cropping seasons with high precipitation in October and with low temperatures in October, November and December. In July during the early eighties, an average of 8% of leaves and 6% of flag leaf sheaths were infected byM. nivalis. Average ear blight incidence was 1.2% glumes infected. Seed contamination by these pathogens averaged 16% in the years 1962–1986. The contamination was high in years with high precipitation in June, July and August. Aspects of cv. resistance and yield loss are illustrated.