Mulching offers protection from Striga asiatica L. Kutnze parasitism in Sorghum genotypes     

Mandumbu Ronald  Mutengwa Charles  Mabasa Stanford  Mwenje Eddie 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2019,69(2):167-173

The production of sorghum is hampered by the parasitic weed Striga asiatica L. Mulching is promoted as a component of the conservation agriculture systems in sub Saharan Africa. The objective of the study was to assess the effects of mulching and Striga infestation on sorghum chlorophyll content, Striga attachments, sorghum height, and yield. The 2?×?2?×?10 factorial experiment was replicated three times for two seasons. The pot experiment was laid out as a completely randomised design. The first factor was mulching at 0 and 3?tons/ha. The second factor was infestation at two levels: infested and uninfested while the third factor was sorghum varieties at 10 levels. Data collected was plant height, chlorophyll content, Striga counts and sorghum yield. Results indicated that mulching increased chlorophyll content in the second season and not first. Infestation reduced chlorophyll content in both seasons. For the second season, mulching increased chlorophyll content in all genotypes except Ruzangwaya, Mukadziusaende and SC Sila. The genotypes Mukadziusaende, Chiredhi and Hlubi were able to maintain height despite infestation by Striga. Generally yield was higher in uninfested pots across all varieties except Mukadziusaende for the first season. Sorghum arundinaceum was highly susceptible to Striga and hence cannot be a source of resistant traits for Sorghum bicolour breeding. Mulching in Striga infested plants increased plant height and chlorophyll content. Mulching tended to diminish the pathological effects of the Striga parasite in some varieties. Therefore, mulching negated the effect of Striga parasitism and resulted in yield maintenance in some genotypes and hence can be taken up by farmers in Striga infested areas as a beneficial cultural practice.  相似文献   

Effects of no tillage and genetic resistance on sunflower wilt by Verticillium dahliae     

F. Quiroz  A. Corro Molas  R. Rojo  J. Prez Fernndez  A. Escande 《Soil & Tillage Research》2008,99(1):66-75

From 2001 to 2006 crop seasons three field experiments were run to compare the effect of no tillage (NT) vs. conventional tillage (CT) on Verticillium wilt of sunflower. One experiment had sunflower monocropping (SM) and the others the sequence wheat–sunflower (WS) with 6 years of fescue pasture or seven WS cycles as previous crops. All experimental fields have history of the disease. One cultivar with low resistance was used in SM and two genotype-resistance levels (high and low; characterized by six and eight cultivars each, respectively) in the WS sequences. Leaf mottle severity in all environments, Verticillium dahliae colony forming units (CFU)/g of soil in 2005 or 2006 trials, density of microsclerotia in the stem pith at 0.5 m above the soil line in WS, and grain yield and oil content in WS with fescue as previous crop were recorded. Every year, disease severity was higher in CT than in NT in all trials. In SM, disease severity increased during the 3 years in CT from 58% to 88%, while in NT disease severity remained around the initial level (49%). The V. dahliae-CFU/g of soil after 3 years in SM or three cycles of WS was approximately three times higher in CT than in NT. In WS, density of microsclerotia in stem pith were higher in CT than in NT. In WS with fescue pasture as previous crop, grain yield and oil content tend to increase with NT in relation to CT. The combination of NT and high-resistant genotypes reduced the disease and the production of microsclerotia in stem pith to very low values. NT + high resistance should be viewed as a preventative, not a curative disease management option because the microsclerotia persist in soil for a long time. Therefore, NT + high resistance programs should be initiated early, before inoculum builds up to high levels in the soil. Thus, the combination of NT and high-resistant cultivars promises to be an interesting tool to manage V. dahliae and Verticillium wilt in sunflower and would have potential in other crops like alfalfa, cotton or strawberry.  相似文献   

湖北省水稻主产区稻田杂草种类及群落特点   总被引：9，自引：2，他引：9  

常向前  李儒海  褚世海  朱文达  陈其志 《中国生态农业学报》2009,17(3):533-536

采用七级目测法调查了湖北省3个水稻主产区25个样点稻田杂草的种类及危害程度,分析了各水稻主产区稻田杂草群落的特点.结果表明,湖北省水稻主产区稻田杂草有23科43种,据综合草害指数优势种杂草依次为稗、双穗雀稗、水花生、鸭舌草、千金子、丁香蓼、鳢肠、浮萍.其中襄樊－随州地区以稗、水花生为优势种类,江汉平原以稗、双穗雀稗为优势种类,黄冈地区以稗、鸭舌草为优势种类.江汉平原与黄冈地区稻田杂草群落相似性较大,Sфrenson相似性指数为0.774 1,二者均与襄樊－随州地区的相似性较小.总体上看,湖北省水稻主产区稻田杂草的丰富度较低,可能与长期施用除草剂有关.  相似文献   

水牛犊人工感染牛巴贝斯虫试验     

赵俊龙刘钟灵  马丽华姚宝安 《中国兽医寄生虫病》1993,1(3):6-9

利用从牛巴贝斯虫病症区采集的镰形扇头蜱叮咬和皮下接种液氨保存的含虫血两种方法，感染去脾和未去脾犊牛，证实了牛巴贝斯虫可以感染水牛犊并使去脾水牛犊发病，但不能使未去脾水牛犊发病。连续注射氢化泼尼松可收提高去脾水牛犊的红细胞染虫率。本试验还详细观察和探讨了水牛巴贝斯虫病的临床症状、虫体在病牛血液中的消长规律、血液学变化及病理解剖学变化。  相似文献   

The Influence of Johnsongrass Infestation and Nitrogen Rates on Grain Sorghum     

G. O. Kegode    U. R. Bishnoi  D. A. Mays 《Journal of Agronomy and Crop Science》1994,172(4):242-246

Gram sorghum [ Sorghum bicolor (L.) Moench] is grown on marginal land and johnsongrass [Sorghum haiepense (L.) Pers] is the most common and hard to control weed in this crop. The agronomic performance of gram sorghum at different nitrogen (N) and johnsongrass infestation levels in the field has not been adequately investigated. Therefore, research was conducted on a Decatur silty clay loam soil (Rhodic Paleudult) to determine the influence of N rates (0, 40, 80 and 120 kg ha^-1) and johnsongrass infestation levels (0, 2, 4, 6 and 8 plants per 5 m crop row) on the growth and yield of grain sorghum (cv. GK522G) and johnsongrass. Increase in N rates increased seed weight, seed yield and percent protein in grain sorghum as well as dry matter and percent protein of johnsongrass. The increase in johnsongrass infestation (from 0 to 8 plants per 5 m crop row) significantly decreased the performance of grain sorghum and johnsongrass at all the N rates. The results suggest that 40 kg N ha^-1 with up to 2 johnsongrass plants per 5 m crop row or 80 kg N ha^-1 with up to 4 johnsongrass plants per 5 m crop row produced grain sorghum yields equivalent to absence of johnsongrass in the crop.  相似文献   

绵羊痒螨寄生移行及侵袭活动的观察   总被引：3，自引：2，他引：1  

陈志蓉  连宏军  徐雪平  柳建新  田晶华  李迎利 《中国兽医寄生虫病》2002,10(4):5-7

对自然感染和人工感染的绵羊痒螨寄生移行、侵袭特点和繁殖活动进行了观察；痒螨寄生由点状寄生逐渐向周围扩散，随着病情加重病灶相接，连接成片的侵袭区，同时对宿主寄生部位皮组织的损伤程度也随病程的深入而加重。  相似文献   

昆虫病原线虫11个品系对星天牛控制能力的研究     

黄金水  林政  高美玲  黄海清  简恒 《中国森林病虫》1997,(2)

该文报道了应用斯氏线虫科的Ｓｔｅｉｎｅｒｎｅｍａ属１０个品系和异杆线虫科的Ｈｅｔ－ｅｒｏｒｈａｂｄｉｔｉｓ属１个品系室内外控制星天牛Ａｎｏｐｌｏｐｈｏｒａｃｈｉｎｅｎｓｉｓ的试验结果。通过１１个线虫品系对星天牛的侵染力测定，筛选出Ｓ．ｆｅｌｔｉａｅＢｅｉｊｉｎｇ和Ｓ．ｃａｒｐｏｃａｐｓａｅＭ．Ｋ．为最佳品系，能寄生中、老龄幼虫，蛹及成虫，４～６天幼虫死亡率可达９４．４％～１００％。以１万条侵染期线虫／每天牛为最适剂量。林间采用带线虫的海绵块塞虫道，效果达９０％～９０．９％。  相似文献   

A retrospective study of juvenile- and adult-onset generalized demodicosis in dogs (1986–91)     

S. L. LEMARIÉ  G. HOSGOOD  C. S. FOIL 《Veterinary dermatology》1996,7(1):3-10

Abstract The medical records of 81 dogs (47 juvenile, 34 adult) with generalized demodicosis were reviewed. There was a significant difference in the distribution of breeds (juvenile P < 0.002, adult P < 0.001; chi squared) presented for demodicosis compared with the distribution of the same breeds presented to our practice during the same time period. Cocker Spaniels and mixed-breed dogs were likely to be under-represented in both the adult- and juvenile-onset groups. Significantly more miticidal treatments were required to achieve clinical remission in adult dogs with pustular demodicosis compared with juvenile dogs with pustular disease (P < 0.05; Kruskall-Wallis). Concurrent disease and associated drug administration were assessed for adult dogs with demodicosis. Of dogs with concurrent conditions (n=15), administration of corticosteroids and endogenous hyperadrenocorticism were recognized most often (10/15). Concurrent neoplastic, infectious, parasitic or metabolic disease was uncommon in dogs with adult-onset demodicosis. Résumé— Les dossiers médicaux de 81 chiens présentant des démodécies généralisées (47 formes juvéniles, 34 formes adultes) ont été analysés. Il existait une différence significative (forme juvénile P < 0.002, forme adulte P < 0.001) dans la distribution des races présentées pour démodécie par rapport aux mêmes races présentées à notre consultation à la même époque. Les cockers spaniels et les chiens métissés sont sous - représentés dans les deux groupes. Le nombre de traitements acaricides nécessaires pour obtenir une rémission clinique était significativement plus élevé chez les chiens adultes présentant une démodécie pustulcuse que chez les jeunes (P < 0.05; Kruskall-Wallis). La présence de pathologies intercurrentes ou iatrogènes a été recherchée chez les chiens adultes. Chez les chiens présentant une pathologie intercurrente (n=15), les diagnostics les plus fréquents (10/15), étaient l'administration de corticoïdes ou un hypercorticisme endogène. Une pathologie intercurrente de type néoplasique, infectieuse, parasitaire ou métabolique est rarement associée à la forme adulte de démodécie canine. [Lemarié, S.L., Hosgood G., Foil C.S. A retrospective study of juvenile- and adult-onset generalized demodicosis in dogs (1986–91) (Analyse retrospective de formes juveniles et de formes adultes de demodecie generalisee chez le chien (1986–91). Veterinary Dermatology 1996; 7 : 3–10.] Resumen Se revisó la historia médica de 81 perros (47 jóvenes, 34 adultos) con demodicosis generalizada. Habia diferencias significativas en la distribución de razas (jóvenes P < 0.002, adulto P < 0.001; chi cuadrado) con una presentación de demodicosis comparado con la distribución de las mismas razas que se presentaron en nuestra consulta durante el mismo período. Los Cocker Spaniel y los cruzados tenían menos posibilidades de presentarse tanto en el grupo de perros jóvenes como en el de adultos. Se necesitaron tratamientos significativamente más miticidas para consequir curación clínica en los perros adultos con demodicosis pustular comparado con los perros jóvenes con presentación pustular (P < 0.05; Kruskall-Wallis). Se detectaron con mayor frecuencia enfermedades concomitantes (n = 15), administración de corticosteroides e hiperadrenocorticismo endógeno (10/15). Fueron poco frecuentes las enfermedades neoplásicas, infecciosas, parasíticas o metabólicas en los casos de demodicosis del adulto. [Lemarié, S.L., Hosgood G., Foil C.S. A retrospective study of juvenile- and adult-onset generalized demodicosis in dogs (1986–91) (Estudio retrospectivo de la demodicosis canina en el adulto y en el perro joven (1986–91). Veterinary Dermatology 1996; 7 : 3–10.] Zusammenfassung— Die Krankenblätter von 81 Hunden (47 juvenil, 34 adult) mit generalisierter Demodikose kamen zur Auswertung. Es bestand einer signifikanter Unterschied in der Verteilung der Rassen (juvenil P < 0,002, adult P < 0,001; Chi-quadrat), die wegen Demodikose vorgestellt wurden, im Vergleich zur der Verteilung der selben Rassen, die während des gleichen Zeitabschnitts in unserer Praxis kamen. Cockerspaniel und Mischlinge schienen unterrepräsentiert sowohl in der Adult- wie in der Juvenil-Demodikosegruppe. Es wurden signifikant mehr akarizide Behandlungen für das Erreichen einer klinischen Remission bei adulten. Hunden mit pustulärer Demodikose benötigt im Vergleich zu juvenilen Hunden mit pustulärer Erkrankung (P < 0,05; Kruskall-Wallis). Bestehende Krankheit und die damit verbundene Arzneimittelanwendung wurden bei adulten Hunden mit Demodikose ausgewertet. Bei Hunden mit bestehenden Krankheitsbildern (n = 15) wurde am häufigsten die Verabreichung von Kortikosteroiden und endogener Hyperadrenokortizismus festgestellt (10/15). Gleichzeitige neoplastische, infektiöse, parasitäre oder stoffwechselbedingte Erkrankung war bei Hunden mit adult-beginnender Demodikose selten. [Lemarié, S.L., Hosgood G., Foil C.S. A retrospective study of juvenile- and adult-onset generalized demodicosis in dogs (1986–91) (Retrospektive Studie über juvenil- und adult-beginnende Demodikose beim Hund (1986–91). Veterinary Dermatology 1996; 7 : 3–10.]  相似文献   

Porous landscapes – The case of Greater Copenhagen     

Anne Gravsholt Busck  Sren Pilgaard Kristensen  Sren Prstholm  Jrgen Primdahl 《Urban Forestry & Urban Greening》2008,7(3):145-156

Many blueprints for urban development argue for the benefits of a sharp distinction between rural and urban space. While such planning designs have been quite successful in maintaining a physical distinction between rural and urban, major transformations of the socio-economic environment in peri-urban areas are creating a more diffuse and porous interface.This paper examines socio-economic consequences of the current transformation of peri-urban areas. Three themes are selected for analysis: changing economies, overall impact of urbanisation as perceived by the individual farm owner and the degree of their local orientation and engagement. Based on case studies in Greater Copenhagen, longitudinal trends and details of the current situation are analysed. In addition, by differentiating between newcomers and long-term residents, possible future changes are indicated. The analysis shows that the importance of agriculture has declined, whereas other gainful activities and residential use have increased. Thus, the functions of the local economy and community are changing. An increasing proportion of the farm owners appreciate the proximity to urban agglomerations (public services, shopping, public transport, social relationships and markets), but this location also has drawbacks, for example in terms of uncertainty concerning future urban development, inconveniences for agricultural production and problems related to public access to private properties.Differences between newcomers and long-time residents are identified. Newcomers without any agricultural background are frequent. They often work outside the municipality and are more frequently personally involved in other gainful activities on-farm. Newcomers perceive more problems related to people accessing the farm properties and are less involved in local activities. In combination, these trends indicate possible future increase in conflicts between farm owners and the public and that the local engagement may be declining. The analysis, however, also shows similarities between newcomers and long-time residents, and therefore does not indicate the development of two cultures or “two nations”. Rather, the urban fringe population is becoming more heterogeneous, ranging from full-time farmers to residents with their social and professional network outside the local area or people engaging in non-agricultural business on-farm.  相似文献   

小圆胸小蠹的研究进展     

何华  伍苏然 《热带作物学报》2016,36(12):66-65

对小圆胸小蠹的分布、寄主、危害、生物学特征以及综合防治措施等方面进行综述，以期为更进一步了解其发生危害特点，达到控制其扩大蔓延和危害，提供一定的理论参考依据。  相似文献