scholarly journals Prevalence and Severity of Nattrassia mangiferae Root and Stem Rot Pathogen of Cassava in Bénin

Plant Disease ◽  
2005 ◽  
Vol 89 (1) ◽  
pp. 12-16 ◽  
Author(s):  
W. Msikita ◽  
B. Bissang ◽  
B. D. James ◽  
H. Baimey ◽  
H. T. Wilkinson ◽  
...  
Keyword(s):  
West Africa ◽  
Root Rot ◽  
Rainy Season ◽  
Disease Incidence ◽  
Macrophomina Phaseolina ◽  
Dry Season ◽  
Stem Cuttings ◽  
Storage Roots ◽  
Fusarium Spp ◽  
Nattrassia Mangiferae

Root rot pathogens were found through diagnostic surveys in all departments (regions) of Bénin, West Africa, to affect 86 to 100% and 96 to 100% of cassava fields during the dry and rainy seasons, respectively. Disease incidence in individual fields ranged between 0 and 53%, and averaged 16 to 27% per department. Nattrassia mangiferae was consistently the most frequently isolated root rot pathogen (56% in the dry season and 22 to 52% in the rainy season). Pathogenicity of N. mangiferae was confirmed on four cultivars of cassava using stem cuttings and storage roots. For all four cultivars, N. mangiferae significantly reduced the number of roots. Lesions (3 to 15 cm long) formed on the lower stem portion of all inoculated plants, whereas control plants remained symptom free. On storage roots, the disease profile was similar to that formed on stem cuttings. Other root rot pathogens detected during the dry season were Macrophomina phaseolina (14.2%), Fusarium spp. (11.8%), Botryodiplodia theobromae (7.7%), and Pythium spp. (2.9%). During the rainy season, Fusarium spp. were the second most commonly isolated root rot pathogens in three departments (Atlantique, Borgou, and Mono). In Oueme and Zou, B. theobromae was the second most isolated root rot pathogen (ranging between 24 and 28%) during the rainy season. During the same season, Pythium spp. were pronounced in Borgou (18%), followed by Mono (11%), Atlantique (9%), Atacora (8%), Oueme (5%), and Zou (6%). Results of the study are discussed with a view to creating awareness of the destructive power of N. mangiferae, a hitherto poorly recognized root rot pathogen of cassava in Bénin and West Africa in general.

Root rot of irrigated lentils in Iran

1980 ◽  
Vol 58 (24) ◽  
pp. 2549-2556 ◽  
Author(s):  
Walter J. Kaiser ◽  
Glenn M. Horner
Keyword(s):  
Root Rot ◽  
Lens Culinaris ◽  
Pythium Ultimum ◽  
Macrophomina Phaseolina ◽  
Field Trials ◽  
Fusarium Spp ◽  
Sources Of Resistance ◽  
Highly Pathogenic ◽  
P Fertilizer ◽  
Greenhouse Tests

In some areas of Iran, root rot of irrigated lentils (Lens culinaris) was a serious problem resulting in high plant mortality and decreased yields. Pythium ultimum was the predominant soil-borne pathogen isolated from discolored, necrotic roots of diseased plants in furrow-irrigated fields at Karaj, and appeared to be the primary incitant of root rot of irrigated lentils at several other locations in the country. Pythium aphanidermatum was the primary pathogen isolated from roots of diseased lentils at two irrigated sites in southern Iran. Isolates of P. ultimum and P. aphanidermatum were highly pathogenic on roots of lentil in greenhouse inoculation studies. Other fungi isolated from diseased lentil roots less frequently were Rhizoctonia solani, Phytophthora sp., Macrophomina phaseolina, Fusarium oxysporum, F. roseum, and F. solani. Cultures of R. solani, Phytophthora sp., and M. phaseolina were less pathogenic on lentil roots than either Pythium sp., whereas the three Fusarium spp. were nonpathogens. Incidence and severity of root rot increased in Karaj field trials in treatments receiving N and P fertilizer and irrigation every 6 days. In greenhouse tests, incidence of root rot increased when naturally infested Karaj soils were amended with 1 or 10% cow manure before planting. Sources of resistance to the lentil root rot complex were found in germplasm screened in naturally infested soils at Karaj.

scholarly journals First Report of Nattrassia mangiferae Root and Stem Rot of Cassava in West Africa

Plant Disease ◽  
1997 ◽  
Vol 81 (11) ◽  
pp. 1332-1332 ◽  
Author(s):  
W. Msikita ◽  
J. S. Yaninek ◽  
M. Ahounou ◽  
H. Baimey ◽  
R. Fagbemissi
Keyword(s):  
West Africa ◽  
Plant Height ◽  
Hot Water ◽  
Day Length ◽  
Stem Rot ◽  
Fusarium Spp ◽  
First Report ◽  
Cassava Root ◽  
Nattrassia Mangiferae ◽  
Number Of Shoots

During part of the dry season in 1996 (November to December), surveys were made for incidence of root and stem rot in 99 fields of cassava (Manihot esculenta Crantz) randomly selected between latitudes 6°36′N and 7°49′N in Benin (79 fields) and Nigeria (20 fields). Root rot was observed in 65 fields in Benin and 15 fields in Nigeria. Disease incidence ranged from 0 to 54%. A total of 201 samples of wilted and/or dead plants were collected for laboratory analysis. Infected root and stem portions (0.5 to 1 cm) were cut out, surface disinfested (10 min) in 10% bleach (0.6% sodium hypochlorite), rinsed in sterilized distilled water, and cultured on potato dextrose agar acidified to pH 4.5 with 0.4% (vol/vol) lactic acid. Cultures were incubated at 25°C, under 12-h day length provided by cool-white fluorescent lamps. After 1 week, mycelia, conidiophores, and conidia were observed at ×30 to ×40 magnification under a compound microscope. Out of the 169 symptomatic samples collected from Benin, nine fungal genera were isolated: Aspergillus spp. (1% of fungi observed), Botryodiplodia theobromae Pat (7.7%), Fusarium spp. (11.8%), Macrophomina phaseolina (Tassi) Goidanich (14.2%), Nattrassia mangiferae (Syd. & P. Syd.) B. Sutton & Dyko (56.2%), Penicillium spp. (0.6%), Pythium spp. (2.9%), Rhizopus spp. (1.7%), and Trichoderma spp. (2.4%). One percent of the fungi isolated did not sporulate in culture and were not identified. Out of the 32 samples collected from Nigeria, four fungal genera were identified: N. mangiferae (40.6%), B. theobromae (28.1%), M. phaseolina (18.7%), and Fusarium spp. (12.5%). Since N. mangiferae was isolated with the highest frequency, its pathogenicity was tested on cassava (cultivars Agric, Ben 86052, Dessa 88, Tchukunochi, and TMS 30572). Two weeks prior to the experiment, inocula for pathogenicity tests were prepared by incubating 5-mm-diameter mycelial plugs of N. mangiferae with 500 ml of autoclaved rice seed for 10 days at 25°C, followed by air drying in a laminar flow hood for 2 days. Five 30-cm-long stem portions were cut from healthy plants of each cassava cultivar, surface disinfested in hot water (52°C, 5 min), and transplanted into sterilized (autoclaved, 1 h) sand in 1-liter pots to which 10 ml of the N. mangiferae-colonized rice inoculum had been added. There were five control stems for each cultivar, similarly treated, but not inoculated. Plants were maintained in a greenhouse under natural light at 28 to 30°C. Thirty days after planting, plant height, lesion length, and number of shoots and roots were recorded. For all five cultivars, N. mangiferae significantly (P < 0.05) reduced plant height and number of shoots and roots, compared with control plants. Lesions (3 to 15 cm long) formed on the lower stem portions of all inoculated plants, resulting in variable degrees of wilting of the infected plants. Two of the cultivars (Agric and Ben 86052) died 3 weeks after planting. Control plants remained asymptomatic. N. mangiferae was consistently reisolated from infected plants, and the identification was independently confirmed by the International Mycological Institute, Surrey, UK. Scytalidium sp., a synamorphic state of N. mangiferae (2), was reported to cause up to 85% cassava root yield loss in South America (1). This is the first report of N. mangiferae causing cassava root and stem rot in West Africa. References: (1) Anonymous. Annu. Rep. Cassava Prog., CIAT Working Doc. No. 116:97, 1992. (2) B. C. Sutton and B. J. Dyko. Mycol. Res. 93:466, 1989.

Screening of wild Solanum rootstock to manage dry root rot disease (Macrophomina phaseolina) in brinjal

1970 ◽  
pp. 34
Author(s):  
J. Sherly, R. Renuka
Keyword(s):  
Root Rot ◽  
Disease Incidence ◽  
Macrophomina Phaseolina ◽  
Solanum Species ◽  
Wild Solanum Species ◽  
Root Rot Disease ◽  
House Condition ◽  
Rot Disease ◽  
Cent Disease ◽  
Wild Solanum

Five wild Solanum species were screened against dry root rot disease in glass house condition with commonly cultivated brinjal as control. The disease was scored at different day’s interval on 30th, 45th and 60th days after planting (DAP). Among the wild species screened and evaluated the species S. torvum was observed without any disease incidence i.e (0). The least per cent of disease incidence was observed in S. incanum (38.60%) which was followed by S. xanthocarpum (42.80%), S. viarum (64.20%) and CO2 (78.50 %) susceptible check at 30 DAP. Secondary metabolites were analysed from both wild and control plants. Based on the per cent disease incidence values S. torvum was graded as ‘Resistant’ against M. phaseolina and can be recommended as a best rootstock for brinjal under varying climatic condition especially where the dry climate prevails.

Management of Dry Root Rot in Chickpea (Cicer arietinum L.) Caused By Macrophomina phaseolina by Utilizing Host Plant Resistance, Fungicides and Bioagents

2020 ◽  
Author(s):  
H. Manjunatha ◽  
M. Saifulla
Keyword(s):  
Host Plant ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Root Rot ◽  
Disease Incidence ◽  
Macrophomina Phaseolina ◽  
Resistant Varieties ◽  
Paper Technique ◽  
Blotter Paper ◽  
Cent Disease

Background: For the management of soil borne disease like dry root rot of chickpea caused by Macrophomina phaseolina, by using fungicides alone is not feasible due to environmental and health hazards. Hence integrated management of the disease by using resistant varieties, fungicides and bio-control agents is the best alternative. So the present study was aimed to identify resistant varieties, best fungicide and bioagent for management of dry root rot in chickpea. Methods: Two hundred and twelve genotypes were screened using blotter paper technique for identifying resistant genotypes for dry root rot. The experiment on management of dry root rot was conducted during Kharif and Rabi of 2013-14 using a susceptible chickpea variety JG-11 with 14 treatments including control with 3 replications. Result: Of two hundred and twelve chickpea genotypes screened for host plant resistance against Macrophomina phaseolina by blotter paper technique only one genotype ie. PBG-5 showed moderately resistant reaction. Among fourteen treatments including fungicides and bioagents imposed for the management of dry root rot, seed treatment with tebuconazole @ 2 g/kg recorded lowest per cent disease incidence of 9.43, with a highest yield of 722.81 kg/ha compared to untreated control which recorded the highest per cent disease incidence (40.10) with a lowest mean yield of 362.02 kg/ha.

scholarly journals Interaction of Fusarium solani, Macrophomina phaseolina and Rhizoctonia solani as root rot pathogens of Cucumis melo

2019 ◽  
Vol 45 (4) ◽  
pp. 355-360
Author(s):  
Maria Alice Formiga Porto ◽  
Márcia Michelle de Queiroz Ambrósio ◽  
Selma Rogéria de Carvalho Nascimento ◽  
Beatriz Letícia Silva da Cruz ◽  
Taffarel Melo Torres
Keyword(s):  
Rhizoctonia Solani ◽  
Fusarium Solani ◽  
Root Rot ◽  
Cucumis Melo ◽  
Yield Loss ◽  
Disease Incidence ◽  
Macrophomina Phaseolina ◽  
Fresh Weight ◽  
Root Diseases ◽  
Mixed Inoculum

ABSTRACT Root diseases represent one of the main reasons for yield loss in melon crops, especially root and stem rots caused by pathogens like the fungi Fusarium solani (Fs), Macrophomina phaseolina (Mp) and Rhizoctonia solani (Rs), frequently observed in muskmelon either alone or in combination. The objective of this study was to evaluate the effect of the interaction between the pathogens Fs, Mp and Rs on the incidence and severity of root rot and muskmelon development. Two greenhouse experiments were performed using plastic pots with substrate infested with each pathogenic agent alone or in combination. The second experiment was conducted in the same pots that were used in the first experiment. In the first experiment, the disease incidence was higher for the treatment with Fs alone. In the second experiment, the disease incidence and severity were greater for treatment Fs + Rs than for Fs alone. Macrophomina phaseolina was the most commonly isolated pathogen when applied to the plants in a paired mixed inoculum (Fs + Mp and Mp + Rs) in the first experiment. In the second experiment, Fs was more prevalent than the other studied pathogens. Soil infested with Fs had the lowest fresh weight of muskmelon. The pathogens Fs and Mp were more competitive than Rs.

EFFECTS OF WATER AVAILABILITY AND VINE HARVESTING FREQUENCY ON THE PRODUCTIVITY OF SWEET POTATO IN SOUTHERN MOZAMBIQUE. III. CROP YIELD/WATER-USE RESPONSE FUNCTIONS

2003 ◽  
Vol 39 (4) ◽  
pp. 409-421 ◽  
Author(s):  
F. GOMES ◽  
M. K. V. CARR
Keyword(s):  
Sweet Potato ◽  
Water Use ◽  
Crop Yield ◽  
Water Availability ◽  
Rainy Season ◽  
Dry Season ◽  
Yield Response ◽  
Root Production ◽  
Total Production ◽  
Storage Roots

In Mozambique the sweet potato (Ipomoea batatas) is grown as both a leafy vegetable, the terminal shoots or vines being progressively harvested during the season, and as a root crop. This paper reports the development of crop yield/water-use production functions using data from two irrigation experiments designed to evaluate the effects of water availability and vine harvesting practices on the productivity and water use (ETc) of sweet potato (cv. TIS 2534) during two contrasting seasons in the south of the country. As the frequency of vine harvesting increased, the water-use efficiency (WUE-ETc) for vine production (dry mass) increased from 1–2 to 4–5 kg ha−1 mm−1 during the rainy season, and from 1 to 9 kg ha−1 mm−1 during the dry season. By contrast, there was a corresponding reduction in the WUE-ETc for storage root production from 14 to 8–9 kg ha−1 mm−1 during the rainy season, and from 23 to 15–17 kg ha−1 mm−1 during the dry season. For the total yields (vines plus storage roots) the WUE-ETc during both seasons were independent of the vine harvesting treatment. Separate lines represented each season, the slopes of which were 13 kg ha−1 mm−1 in the rains, and 24 kg ha−1 mm−1 in the dry season. When, however, crop water-use was normalised using either the seasonal mean daily total of incoming solar radiation, or reference crop evapotranspiration (ETo), but not the saturation deficit of the air, a single common, linear relationship with yield resulted. Possible explanations for this are considered. Plotting relative yields against relative rates of water-use, also gave consistent results that could have general application for predicting the effects of water availability on productivity. Vine yields, when harvested frequently, were less sensitive to drought (yield response factor, Ky=0.7–0.9) than storage roots (Ky=1.2). For total production (vines plus roots), the sensitivity to water stress (Ky) increased, from 0.9–1.0 to 1.2, as the interval between vine harvests increased. Farmers in southern Mozambique trying to maximize total yield during the season, under conditions of water uncertainty, should harvest vines at intervals of not more than 14 days.

scholarly journals BIODIVERSIDADE DE BACTÉRIAS ANTAGÔNICAS A FUNGOS ASSOCIADOS À SINDROME DA MORTE DO CAPIM-MARANDU (Brachiaria brizantha)

Nativa ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 454-459
Author(s):  
Maira Laís Both Bourscheidt ◽  
Kellen Banhos do Carmo ◽  
Bruno Carneiro Pedreira ◽  
Gilcele de Campos Martin Berber ◽  
Anderson Ferreira
Keyword(s):  
Biological Control ◽  
Rainy Season ◽  
Production Systems ◽  
Dry Season ◽  
Native Forest ◽  
Bacterial Isolates ◽  
Fusarium Spp ◽  
Brachiaria Brizantha

A síndrome da morte do capim-marandu (Brachiaria brizantha) é um dos principais problemas na degradação das pastagens no bioma Amazônia. A morte das forrageiras ocorre durante a época chuvosa por suscetibilidade a fitopatógenos. Assim, objetivou-se estudar sistemas de produção e selecionar bactérias antagônicas a Fusarium spp., um dos agentes fitopatogênicos. Os isolados bacterianos foram obtidos de 10 sistemas de produção, mata nativa e pousio, na chuva e na seca. Realizou-se a caracterização molecular de isolados por sequenciamento. Dois isolados de Fusarium foram testados. Para o patógeno 1, na época da chuva, 7,5% dos isolados apresentaram antagonismo enquanto na seca foi 15%. Para o patógeno 2, nem todos os isolados positivos para o patógeno 1 foram eficientes no controle, demonstrando a ocorrência de interações entre isolados bacterianos e Fusarium spp. Na chuva, para o patógeno 1, a mata apresentou maior número de isolados positivos (20%). Na seca, os tratamentos mata, 1-Floresta e 8-integração lavoura floresta para o patógeno 1, foram os que apresentaram maior número de positivos (25%). Na identificação molecular, 8 foram os gêneros bacterianos encontrados: Burkholderia, Bacillus, Brevibacillus, Streptomyces, Pseudomonas, Escherichia, Paenibacillus e Pandoraea, em que a maioria é descrita como capaz de controlar Fusarium spp. in vitro. Palavras-chave: Burkholderia; controle biológico; integração lavoura-pecuária-floresta.   Biodiversity of bacteria antagonic to fungi associated with syndrome's death palisadegrass (Brachiaria brizantha)   ABSTRACT: The death syndrome of marandu grass (Brachiaria brizantha) is one of the main problems in the degradation of pastures in the Amazon biome. Plant death occurs during the rainy season due to susceptibility to phytopathogens. Thus, the objective was to study production systems and select bacteria antagonistic to Fusarium spp., one of the phytopathogenic agents. Bacterial isolates were obtained from 10 production systems, native forest and fallow, in rain and drought season. Molecular characterization of isolates was carried out by sequencing. Two Fusarium isolates were assessed. For pathogen 1, in the rainy season, 7.5% of the isolates showed antagonism, while in the dry season it was 15%. For pathogen 2, not all isolates positive for pathogen 1 were efficient in the control, showing correlations between bacterial isolates and Fusarium spp. In the rain, for pathogen 1, the forest showed the highest number of positive isolates (20%). In the dry season, the treatments forest, 1-Forest and 8-plant-forest integration for pathogen 1, were ones with the highest number of positives (25%). In the molecular identification, 8 bacterial genera were found: Burkholderia, Bacillus, Brevibacillus, Streptomyces, Pseudomonas, Escherichia, Paenibacillus and Pandoraea, most of which are described as able to controlling Fusarium spp. in vitro. Keywords: Burkholderia; biological control; integrated crop-livestock-forest.

scholarly journals First Report of Erwinia carotovora subsp. carotovora Causing Bacterial Root Rot of Sweetpotato (Ipomoea batatas) in Louisiana

Plant Disease ◽  
1998 ◽  
Vol 82 (1) ◽  
pp. 129-129 ◽  
Author(s):  
C. A. Clark ◽  
M. W. Hoy ◽  
J. P. Bond ◽  
C. Chen ◽  
Y.-K. Goh ◽  
...  
Keyword(s):  
Root Rot ◽  
Ipomoea Batatas ◽  
Disease Incidence ◽  
Erwinia Carotovora ◽  
Soft Rot ◽  
Stem Rot ◽  
Identification System ◽  
Natural Occurrence ◽  
Storage Roots ◽  
First Report

Bacterial root and stem rot of sweetpotato (Ipomoea batatas (L.) Lam.) was first fully characterized in the U.S. in 1977 (2). It was thought to be caused exclusively by Erwinia chrysanthemi. Although a previous report described sweetpotato as a host for E. carotovora subsp. carotovora, based on artificial inoculations, others have reported that neither E. carotovora subsp. carotovora nor E. carotovora subsp. atroseptica decay sweetpotato storage roots (1). In October 1995, storage roots of sweetpotato cv. Beauregard were received from St. Landry Parish, LA, that displayed typical bacterial root rot. Isolations from these roots yielded bacteria that showed a similarity of 0.945 to E. carotovora subsp. carotovora with the Biolog GN Bacterial Identification System (version 3.50). This isolate (Ecc-LH) also differed from isolates of E. chrysanthemi (Ech) from sweetpotato and other hosts in that it was insensitive to erythromycin, did not produce phosphatase or lecithinase, and did not produce gas from glucose. Ecc-LH differed from known strains of E. carotovora subsp. atroseptica in that it did not produce reducing substances from sucrose or acid from palatinose. When Beauregard storage roots were inoculated by inserting micropipette tips containing 50 μl of 1.0 × 108 CFU/ml, both Ecc-LH and Ech-48 produced typical bacterial root rot symptoms. However, when they were compared by infectivity titrations at 28 to 32°C, Ecc-LH was less virulent than Ech-48. Ecc-LH had an ED50 of approximately 1.0 × 106 CFU/ml and did not cause appreciable disease below inoculum concentrations of 1.0 × 105, whereas Ech-48 had an ED50 of approximately 1.0 × 108 and caused soft rot at the lowest concentration tested, 1.0 × 103. Similar disease incidence was observed in infectivity titrations at 22 to 24°C, but Ech-48 caused less severe soft rot. E. carotovora subsp. carotovora was reisolated from inoculated storage roots and its identity was reconfirmed by Biolog. When terminal vine cuttings of Beauregard were dipped in 1.0 × 108 CFU/ml and planted in a greenhouse, bacterial stem rot symptoms developed on plants inoculated with Ech-48 at about 4 weeks postinoculation, or when new growth began. However, no symptoms developed on plants inoculated with Ecc-LH. This is the first report of natural occurrence of E. carotovora subsp. carotovora causing bacterial root rot of sweetpotato in Louisiana. E. chrysanthemi remains the most important pathogen causing bacterial soft rot in sweetpotato since it is widely associated with sweetpotato, is more virulent on storage roots and also causes a stem rot. E. carotovora subsp. carotovora can cause root rot, but has been isolated in only one location to date, is less virulent on storage roots, and apparently does not cause stem rot on the predominant cultivar in U.S. sweetpotato production, Beauregard. References: (1) C. A. Clark and J. W. Moyer. 1988. Compendium of Sweet Potato Diseases. American Phytopathological Society, St. Paul, MN. (2) N. W. Schaad and D. Brenner. Phytopathology 67:302, 1977.

scholarly journals Effects of seasonal variation in temperature and cultivar on yield and yield determination of irrigated groundnut (Arachis hypogaea) during the dry season in the Sahel of West Africa

1998 ◽  
Vol 131 (4) ◽  
pp. 439-448 ◽  
Author(s):  
B. R. NTARE ◽  
J. H. WILLIAMS ◽  
B. J. NDUNGURU
Keyword(s):  
West Africa ◽  
Arachis Hypogaea ◽  
Growth Rates ◽  
Rainy Season ◽  
Sowing Date ◽  
Crop Growth ◽  
Dry Season ◽  
Pod Yield ◽  
Sowing Dates ◽  
Yield Determination

In the Sudano-Sahelian zone of West Africa there is potential for groundnut (Arachis hypogaea L.) to be grown as a dry-season crop where irrigation is available. However, there are substantial variations in the temperatures during the post-rainy season that can be expected to influence growth and yield. An experiment at the ICRISAT Sahelian Centre was done in order to study the effect of sowing date on phenology, yield and the processes of yield determination for four groundnut cultivars under irrigation in the dry seasons of 1990/91 and 1991/92. Starting on 15 November, eight sowing dates at 2-weekly intervals were tested. Sowing date significantly affected phenology (time to emergence, flowering and maturity) with groundnut sown in November/December taking the longest time to reach these phenological stages. November and December sowings gave the highest pod yield within each year, despite the lowest crop growth rates (B), and yield declined progressively as sowing occurred later (50% decrease by March) despite increasing B. The observed responses appear to have been due to the effect of temperature differences during the pod-filling phase on partitioning. Partitioning (p) to pods was optimized at c. 30 C, with some indication of cultivar differences in partitioning response to temperature. Across all the environments, cultivars displayed substantial differences in yield stability. When sown late, yields were low and lines with high partitioning were the best. When sown early in the post-rainy season, cultivars with a high B value were the better choices. Plant habit differences and B suggest that radiation interception was a limitation to yield, particularly when the crops were sown in the cool months of the year. However, haulm yield and crop growth rates were not consistently affected by sowing date across the years, and cultivars demonstrated different degrees of stability for B. It is concluded that where pod has a price advantage over fodder, irrigated groundnut for the dry season should be sown in November to allow the crop to develop under the relatively cool temperatures that maximize pod yield. Further agronomic research is suggested to maximize B for individual cultivars for given sowing dates.

scholarly journals Temporal variability of mineral dust concentrations over West Africa: analyses of a pluriannual monitoring from the AMMA Sahelian Dust Transect

2010 ◽  
Vol 10 (18) ◽  
pp. 8899-8915 ◽  
Author(s):  
B. Marticorena ◽  
B. Chatenet ◽  
J. L. Rajot ◽  
S. Traoré ◽  
M. Coulibaly ◽  
...  
Keyword(s):  
West Africa ◽  
Rainy Season ◽  
Seasonal Cycle ◽  
Mineral Dust ◽  
General Pattern ◽  
Regional Scale ◽  
Surface Wind ◽  
Dry Season ◽  
Dust Concentration ◽  
Saharan Dust

Abstract. The Sahelian belt is known to be a region where atmospheric levels of suspended mineral dust are among the highest observed on Earth. In the framework of the AMMA (African Monsoon Multidisciplinary Analysis) International Program, a transect of 3 ground based stations, the "Sahelian Dust Transect" (SDT), has been deployed in order to obtain quantitative information on the mineral dust content and its variability over the Sahel. The three stations, namely Banizoumbou (Niger), Cinzana (Mali) and M'Bour (Senegal) are aligned around 14° N along the east-westward main pathway of the Saharan and Sahelian dust towards the Atlantic Ocean. We discuss data collected between January 2006 and December 2008 to investigate the main characteristics of the mineral dust concentration over West Africa and their connection with the dominant meteorological situations. The succession of the dry season during which the Sahel is under the influence of the dry Harmattan wind and the wet season induced by the entrance of the monsoon flow is clearly identified from the basic meteorological parameters (air temperature and moisture, wind direction). Atmospheric dust concentrations at the three stations exhibit a similar seasonal cycle, with a monthly maximum during the dry season and a minimum occurring during the rainy season, indicating that the general pattern of dust concentration is similar at regional scale. This seasonal cycle of the dust concentrations is not phased with the seasonal cycle of surface wind velocity locally measured, suggesting that it is mainly controlled by Saharan dust transport. Local dust emissions induced by strong surface winds are responsible for the occurrence of extremely high daily concentrations observed at the beginning of the rainy season. A decrease in the dust concentration is observed when moving from Niger to Senegal.

Sign in / Sign up

Export Citation Format

Share Document