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田间调查是一种评估害虫及天敌种群数量的科学方法。田间调查的方法很多,为比较不同调查方法之间的准确性差异,笔者曾用目测法、水盆法、粘板法、吸虫法对水稻害虫及天敌作过调查,现将结果整理如下:材料与方法调查田面积约0.5亩,品种为 IR—72,水稻正处于幼穗分化始期。调查时,将调查田分成4个小区,每个小区用下列4种方法之一调查20丛稻上的害虫及天敌数量。这4种调查方法是:1.目测法:即用眼睛直接计数水稻上的害虫及天敌数量。为使害虫及天敌不因人为 相似文献
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要保护天敌,对害虫各代的天敌都要加以注意,害虫越冬代的天敌更不能忽视。调查害虫越冬代的天敌寄生率对预测当年害虫发生程度和采取相应措施保护害虫越冬代天敌是有意义的。虽然某些害虫越冬代天敌寄生率的调查较困难,但为探明害虫越冬代寄生率状况,我们对水稻主要害虫越冬代天敌寄生率进行了调查。现将1976年以来调查结果分述如下。 相似文献
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萧氏松茎象入侵南昌地区 总被引：1，自引：0，他引：1
2003年4月16日,在南昌市安义县新华林场与东阳镇黄城村山上余家毗邻处,发现森林新害虫——萧氏松茎象。因该害虫在南昌是首次发现,市、县政府、林业部门对此高度重视,立即成立该害虫调查工作领导机构,市林业局专门下文,精心组织各县(区)对所辖范围的松林(湿地松为主)进行了一次系统地、全面地调查。经过近两个月的认真、细致、艰辛调查,初步查清了该害虫在全市的分布、发生和危害情况。目前该害虫还只分布在安义县,但该县此害虫来势凶猛,发生面积大,危害情况严重。调查统计,分布面积9648.0 hm2,发生面积7591.3 hm2,其中,重度发生面积有3682.… 相似文献
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荧光假单胞杆菌的嗜铁素是控制桉树灰霉病的主要因子 总被引：5，自引：0，他引：5
本文对3个假单胞杆菌菌株(Pseudomonas spp.)及其嗜铁素(pseudobactin siderophore)缺失突变体防治桉树灰霉病进行了研究.平板拮抗活性测定表明,荧光假单胞杆菌(P.fluorescens) WCS374r菌株和恶臭假单胞杆菌(P.putida) WCS358r菌株通过对铁离子的竞争抑制灰霉菌的生长.在接种灰霉病菌之前10 h将WCS358r、WCS374r和WCS417r施用于受伤的桉树叶片后,可分别降低发病率48.9%、58.3%和40.3%;当将3种生防菌分别与灰霉病菌混合后接种桉树叶片,WCS358r和WCS374r仍然能够显著地降低发病率;在接种灰霉病菌12 h后再施用生防菌,WCS358r和WCS374r对病菌仍具有一定的抑制作用,而在24 h后施用生防菌,3个菌株均未表现显著的防治效果.WCS358r和WCS417r的嗜铁素缺失突变体无防病作用,而WCS374r的嗜铁素缺失突变体虽然还能有效地防治灰霉病,但与WCS374r相比,防病效果减弱.本试验结果说明假单胞杆菌的嗜铁素是控制桉树灰霉病的重要因子. 相似文献
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ABSTRACT The role of bacterially produced salicylic acid (SA) in the induction of systemic resistance in plants by rhizobacteria is far from clear. The strong SA producer Pseudomonas fluorescens WCS374r induces resistance in radish but not in Arabidopsis thaliana, whereas application of SA leads to induction of resistance in both plant species. In this study, we compared P. fluorescens WCS374r with three other SA-producing fluorescent Pseudomonas strains, P. fluorescens WCS417r and CHA0r, and P. aeruginosa 7NSK2 for their abilities to produce SA under different growth conditions and to induce systemic resistance in A. thaliana against bacterial speck, caused by P. syringae pv. tomato. All strains produced SA in vitro, varying from 5 fg cell(-1) for WCS417r to >25 fg cell(-1) for WCS374r. Addition of 200 muM FeCl(3) to standard succinate medium abolished SA production in all strains. Whereas the incubation temperature did not affect SA production by WCS417r and 7NSK2, strains WCS374r and CHA0r produced more SA when grown at 33 instead of 28 degrees C. WCS417r, CHA0r, and 7NSK2 induced systemic resistance apparently associated with their ability to produce SA, but WCS374r did not. Conversely, a mutant of 7NSK2 unable to produce SA still triggered induced systemic resistance (ISR). The possible involvement of SA in the induction of resistance was evaluated using SA-nonaccumulating transgenic NahG plants. Strains WCS417r, CHA0r, and 7NSK2 induced resistance in NahG Arabidopsis. Also, WCS374r, when grown at 33 or 36 degrees C, triggered ISR in these plants, but not in ethylene-insensitive ein2 or in non-plant pathogenesis- related protein-expressing npr1 mutant plants, irrespective of the growth temperature of the bacteria. These results demonstrate that, whereas WCS374r can be manipulated to trigger ISR in Arabidopsis, SA is not the primary determinant for the induction of systemic resistance against bacterial speck disease by this bacterium. Also, for the other SAproducing strains used in this study, bacterial determinants other than SA must be responsible for inducing resistance. 相似文献
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Zanna Muhammad 《European journal of plant pathology / European Foundation for Plant Pathology》1994,100(6):413-423
Over a period of 12 months new and old cysts ofGlobodera pallida were hatched in potato root diffusate according to a novel nematode-response hatching protocol. In this protocol, cysts were set to hatch at the beginning of autumn and then left to indicate when their hatching ability was exhausted (when less than 100 juveniles/replicate/week emerged) before another batch of cysts was set to hatch. At any time of the year for the 12 months this experiment was conducted there were cysts hatching. After 12 months of hatching, eight hatching curves were obtained. Based on the hatching curves of the new and old cysts, diapause was shown to be present in new cysts in autumn, winter and early spring. However, diapause was absent in late spring and summer.Infectivity assays to distinguish between juveniles obtained in the periods when cysts were in diapause and when cysts had overcome their diapause failed to show any significant difference in their infectivity. There was no significant difference in the number of eggs in new and old cysts. Based on this observation, it was suggested that high emergence in old cysts may not be a result of few eggs in the cyst but rather due to absence of diapause. Also the presence of large numbers of eggs in old cysts even after being stored for 12 months outdoors in the soil does not support the theories of spontaneous hatching, micro-organism induced hatching or persistence of hatching factors in the soil. 相似文献
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为了明确河北省不同地区棉蚜种群对主要杀虫剂的抗性水平及其发展趋势,采用浸渍法,于2014—2020年分别测定了河北省保定、沧州和邯郸地区棉蚜种群对6种杀虫剂的敏感性。结果表明:与国内历史敏感基线相比较,河北省棉蚜对高效氯氰菊酯、丁硫克百威、吡虫啉和氟啶虫胺腈的抗性均达到高抗至极高抗水平,抗性最高分别达到242、13353、1367和205倍;对氧乐果和噻虫嗪的抗性也达到中等至高水平抗性。应用Pearson相关性分析评估各药剂的logLC50值的相关性,发现保定种群对吡虫啉和氟啶虫胺腈 (r = 0.77, p = 0.041)、噻虫嗪和氟啶虫胺腈 (r = 0.98, p < 0.001) 的抗性呈显著正相关;沧州种群对高效氯氰菊酯和丁硫克百威 (r = 0.81, p = 0.027)、高效氯氰菊酯和噻虫嗪 (r = 0.90, p = 0.006)、丁硫克百威和噻虫嗪 (r = 0.91, p = 0.005) 的抗性呈显著正相关;邯郸种群对高效氯氰菊酯和噻虫嗪 (r = 0.83, p = 0.022)、高效氯氰菊酯和氟啶虫胺腈 (r = 0.97, p < 0.001)、丁硫克百威和氟啶虫胺腈 (r = 0.77, p = 0.045) 的抗性呈显著正相关。本研究结果表明,河北省棉蚜种群对6种杀虫剂的抗性显著,且可能存在严重的交互抗性。 相似文献
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Soft rock efficiently retains water because it is hard when dry but expands rapidly when wet, thus it can be used as a natural water retention agent. Therefore, soft rock can be blended with sandy soil to enhance the water-holding capacity of sandy land. Understanding how soft rock content in sandy soil affects corn growth (Zea mays L.) is essential for enhancing local agricultural production in the Mu Us Desert. The Root Zone Water Quality Model 2 was calibrated and validated based on 2-years of experimental data for composite soils prepared at three ratios of soft rock to sand (1:1, 1:2, and 1:5 v/v), and then used to estimate the water non-limiting potential yield (Yp) and the potential yield of a rainfed crop [Yp(r)], along with yield gap [YG(r)] of corn using the weather data from 1990 to 2013 in the Mu Us Desert. The mean simulated Yp(r) of corn in the compound soil at a ratio of 1:2 was significantly higher than that of the compound soil at 1:1 and 1:5 ratios, respectively. The mean simulated Yp(r)s of corn were 2.551, 3.527, and 2.924?Mg ha?1 and the YG(r)s were 6.071, 5.096, and 5.698?Mg ha?1 for 1:1, 1:2, and 1:5 ratios, respectively. The crop yield depends on the amount of soft rock added to the sandy soils. 相似文献
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ABSTRACT The association between Fusarium head blight (FHB) intensity and deoxynivalenol (DON) accumulation in harvested grain is not fully understood. A quantitative review of research findings was performed to determine if there was a consistent and significant relationship between measures of Fusarium head blight intensity and DON in harvested wheat grain. Results from published and unpublished studies reporting correlations between DON and Fusarium head blight "index" (IND; field or plot-level disease severity), incidence (INC), diseased-head severity (DHS), and Fusarium-damaged kernels (FDK) were analyzed using meta-analysis to determine the overall magnitude, significance, and precision of these associations. A total of 163 studies was analyzed, with estimated correlation coefficients (r) between -0.58 and 0.99. More than 65% of all r values were >0.50, whereas less that 7% were <0. The overall mean correlation coefficients for all relationships between DON and disease intensity were significantly different from zero (P < 0.001). Based on the analysis of Fisher-transformed r values ( z(r) values), FDK had the strongest relationship with DON, with a mean r of 0.73, followed by IND (r = 0.62), DHS (r = 0.53), and INC (r = 0.52). The mean difference between pairs of transformed z(r) values (z(d) ) was significantly different from zero for all pairwise comparisons, except the comparison between INC and DHS. Transformed correlations were significantly affected by wheat type (spring versus winter wheat), study type (fungicide versus genotype trials), and study location (U.S. spring- and winter-wheat-growing regions, and other wheat-growing regions). The strongest correlations were observed in studies with spring wheat cultivars, in fungicide trials, and in studies conducted in U.S. spring-wheat-growing regions. There were minor effects of magnitude of disease intensity (and indirectly, environment) on the transformed correlations. 相似文献
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Siderophore-mediated competition for iron and induced resistance in the suppression of fusarium wilt of carnation by fluorescent Pseudomonas spp 总被引：4，自引：0，他引：4
Ben J. Duijff Jan W. Meijer Peter A. H. M. Bakker Bob Schippers 《European journal of plant pathology / European Foundation for Plant Pathology》1993,99(5-6):277-289
The mechanisms of suppression of fusarium wilt of carnation by two fluorescentPseudomonas strains were studied.Treatments of carnation roots withPseudomonas sp. WCS417r significantly reduced fusarium wilt caused byFusarium oxysporum f. sp.dianthi (Fod). Mutants of WCS417r defective in siderophore biosynthesis (sid–) were less effective in disease suppression compared with their wild-type. Treatments of carnation roots withPseudomonas putida WCS358r tended to reduce fusarium wilt, whereas a sid– mutant of WCS358 did not.Inhibition of conidial germination of Fod in vitro by purified siderophores (pseudobactins) of bothPseudomonas strains was based on competition for iron. The ferrated pseudobactins inhibited germination significantly less than the unferrated pseudobactins. Inhibition of mycelial growth of Fod by bothPseudomonas strains on agar plates was also based on competition for iron: with increasing iron content of the medium, inhibition of Fod by thePseudomonas strains decreased. The sid– mutant of WCS358 did not inhibit Fod on agar plates, whereas the sid– mutants of WCS417r still did. This suggests that inhibition of Fod by WCS358r in vitro was only based on siderophore-mediated competition for iron, whereas also a non-siderophore antifungal factor was involved in the inhibition of Fod by strain WCS417r.The ability of thePseudomonas strains to induce resistance against Fod in carnation grown in soil was studied by spatially separating the bacteria (on the roots) and the pathogen (in the stem). Both WCS417r and its sid– mutant reduced disease incidence significantly in the moderately resistant carnation cultivar Pallas, WCS358r did not.It is concluded that the effective and consistent suppression of fusarium wilt of carnation by strain WCS417r involves multiple mechanisms: induced resistance, siderophore-mediated competition for iron and possibly antibiosis. The less effective suppression of fusarium wilt by WCS358r only depends on siderophore-mediated competition for iron. 相似文献
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二氯乙酰二异丙胺对绿磺隆解毒的生物测定研究 总被引：2，自引：0，他引：2
利用简便，快速和准确的生测方法，研究二氯乙酰二异丙胺作为安全剂对绿磺隆的解毒效果，选用东农小粒１５６玉米种子为指示作物，在黑暗条例上２６℃和３３℃培养箱中培养７２ｈ，玉米的根长，根干重，芽长和芽干重与安全剂的浓度呈直线关系，证明二氯乙酰二异丙胺能保护玉米免疫绿磺隆的药害。 相似文献
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Adult plant resistance to powdery mildew (Erysiphe graminis)in three barley cultivars 总被引：3，自引：2，他引：1
The mechanism(s) of adult plant resistance (a.p.r.) to Erysiphe graminis f. sp. hordei were examined in two spring barley cultivars, Athos and Porthos, which possess similar identified mildew resistance genes and seedling resistance, but differential field resistance. These cultivars were compared with Golden Promise, a universally susceptible cultivar. Differential a.p.r. to a compatible race was detected as a reduction in the number and sporulation of colonies on later-formed Athos leaves. Golden Promise exhibited some a.p.r., but much less than either Athos or Porthos. Differential a.p.r. was expressed at several infection stages, viz. appressorial formation, penetration and sporulation. Epidermal hypersensitivity occurred infrequently in all leaf position/cultivar interactions. Papillae were associated with >90% of all penetration failures. The incidence of papillae in successful penetrations at 96 h was 20% on later-formed leaves of Athos compared to c. 60% on all other leaves. 相似文献
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Ö. Baysal M. Siragusa H. İkten İ. Polat E. Gümrükcü F. Yigit F. Carimi J.A. Teixeira da Silva 《Physiological and Molecular Plant Pathology》2009,74(1):68-75
Fusarium oxysporum f. sp. lycopersici (FOL) races and F. oxysporum f. sp. radicis lycopersici (FORL), the causal agents of root rot and crown rot diseases, respectively, cause serious economic losses in tomato greenhouses where production is intensive in the West Mediterranean region of Turkey. The isolates were collected from West Mediterranean region of Turkey and were characterized by specific primers based on three races (r1, r2, r3), besides pathogenicity tests in in vivo conditions Additionally, a scheme was developed using newly tested ISSR and SRAP markers to a genotyping database and to determine the possible origin of these pathogens. The present study provided new information on these pathogens based on their races and their dominant existence in this region that has not been reported before. Genetic diversity detected in the same races of the pathogen may be associated with difficulties in controlling the pathogen and a possible resistance formation effort exerted by the pathogen to chemicals used in plant protection in tomato greenhouses. Molecular analyses indicated genetic diversity in pathogen isolates identified as r3, r2 and FORL, which may be associated with abiotic stress to which the pathogens were exposed. 相似文献