scholarly journals Occurrence and Distribution in Rwanda of Soilborne Fungi Pathogenic to the Common Bean

Plant Disease ◽  
1997 ◽  
Vol 81 (5) ◽  
pp. 445-449 ◽  
Author(s):  
Gerard Rusuku ◽  
Robin A. Buruchara ◽  
Martin Gatabazi ◽  
Marcial A. Pastor-Corrales

The occurrence and distribution of soilborne fungi pathogenic to the common bean were determined by surveys conducted in seven of Rwanda's 10 prefectures during four growing seasons from 1989 to 1990. The pathogens were identified on the basis of symptoms, colony characteristics, reproductive structures, and pathogenicity tests. Of the plants sampled during the March through June 1989 season from four prefectures, 97% exhibited symptoms associated with soilborne pathogens. Root and hypocotyl symptoms appeared in plants sampled during the September through December 1989 season from the prefectures of Kigali (19%), Butare (40%), Gikongoro (33%), and Cyangugu (33%) and during the March through June 1990 season from Gisenyi (60%) and Kibungo (53%). Pythium spp., Macrophomina phaseolina, Rhizoctonia solani, and Fusarium oxysporum f. sp. phaseoli were isolated from all seven prefectures during all four seasons. Sclerotium rolfsii was isolated only during the 1990 September through December season. The frequency of isolation varied by region and season. Pythium spp. were the most frequently isolated fungi from about 40% of the samples, suggesting their potential importance in the root rot complex in Rwanda. The relative importance of the soilborne pathogens and possible relationships with existing cropping systems are discussed. These results will help focus efforts in developing management strategies for common bean diseases caused by soilborne pathogens in Rwanda.

2003 ◽  
Vol 28 (2) ◽  
pp. 131-135 ◽  
Author(s):  
Álvaro M. R. Almeida ◽  
Lilian Amorim ◽  
Armando Bergamin Filho ◽  
Eleno Torres ◽  
José R. B. Farias ◽  
...  

The increase in incidence of charcoal rot caused by Macrophomina phaseolina on soybeans (Glycine max) was followed four seasons in conventional and no-till cropping systems. In the 1997/98 and 2000/01 seasons, total precipitation between sowing and harvest reached 876.3 and 846.9 mm, respectively. For these seasons, disease incidence did not differ significantly between the no-till and conventional systems. In 1998/99 and 1999/00 precipitation totaled 689.9 and 478.3 mm, respectively. In 1998/99, in the no-till system, the disease incidence was 43.7% and 53.1% in the conventional system. In 1999/00 the final incidence was 68.7% and 81.2% for the no-till and conventional systems, respectively. For these two seasons, precipitation was lower than that required for soybean crops (840 mm), and the averages of disease incidence were significantly higher in the conventional system. The concentration of microsclerotia in soil samples was higher in samples collected in conventional system at 0 - 10 cm depth. However, analysis of microsclerotia in roots showed that in years with adequate rain no difference was detected. In dry years, however, roots from plants developed under the conventional system had significantly more microsclerotia. Because of the wide host range of M. phaseolina and the long survival times of the microsclerotia, crop rotation would probably have little benefit in reducing charcoal rot. Under these study conditions it may be a better alternative to suppress charcoal rot by using the no-till cropping system to conserve soil moisture and reduce disease progress.


2020 ◽  
Vol 46 (4) ◽  
pp. 299-304
Author(s):  
Eduardo José Zanella ◽  
Juliano Berghetti ◽  
Bruno Tabarelli Scheidt ◽  
Ricardo Trezzi Casa ◽  
Amauri Bogo ◽  
...  

ABSTRACT Macrophomina phaseolina is a soilborne pathogen with a wide range of hosts and its control through agricultural practices is difficult. The aim of this study was to quantify the severity of root rot (SRR) caused by M. phaseolina in common bean cultivars and its impact on yield components. The experiments were carried out under greenhouse conditions with the common bean cultivars ‘ANFC-9 Agro Norte’, ‘BRS Esteio’, ‘BRS Estilo’, ‘BRS Pérola’, ‘FTS Soberano’, ‘IPR Campos Gerais’, ‘IPR Tangará’, ‘IPR Tuiuiú’, ‘IPR Uirapurú’ and ‘TAA Dama’. Three isolates of M. phaseolina obtained from infected plants of common bean, soybeans and maize were inoculated in the common bean cultivars. In the phenological stage R9 of grain harvest maturity, the SRR and the yield components of root dry mass (RDM), number of pods per plant (NPP), number of grains per plant (NGP) and grain mass per plant (GMP) were assessed. All common bean cultivars were susceptible to M. phaseolina, showing a reduction in NPP, NGP and GMP. SPR was greater than 75%, regardless of the origin of isolates. Considering the average of cultivars, there was a significant decrease of 54.3% in RDM, compared to control treatments. The cultivars ‘IPR Tangará’, ‘ANFC-9 Agro Norte’, ‘BRS Esteio’, ‘BRS Pérola’ and ‘FTS Soberano’ had a decrease in at least one yield component, while a reduction occurred in all components for cultivar ‘IPR Tangará’. There was an average decrease in NPP, NGP and GMP of 7.9%, 7.6% and 7.2%; 13.4%, 12.8% and 6.7%; and 14.2%, 12.9% and 10.1%, considering the isolates obtained from beans, soybeans and maize, respectively.


PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246281
Author(s):  
Ivan P. Novotny ◽  
Pablo Tittonell ◽  
Mariela H. Fuentes-Ponce ◽  
Santiago López-Ridaura ◽  
Walter A. H. Rossing

Around 30% of global food is produced by smallholder farmers, yet they constitute the most food-insecure group. In Mexico, food self-sufficiency is declining. Rural policies in the country have stimulated the production of cash crops to the detriment of the traditional intercropping system, the milpa. Such a decline may have negative consequences for the food security of subsistence farmers. This study aimed to assess changes in nutritional self-sufficiency over the last 30 years and the role of milpa systems in food security for two communities in the highlands of Oaxaca, Mexico. The study used satellite images, censuses, and field data to estimate food production. Three cropping systems, monoculture of maize, monoculture of common bean, and the milpa were compared in terms of nutrients and vitamins produced. Furthermore, a household typology was developed for each community to contrast nutritional self-sufficiency levels between the different household types. Results showed that the milpa produced more volume of food per area compared to the other systems. The milpa also produced all the nutrients and vitamins (except for B12) required to feed at least 2 persons ha-1. Monocultures of maize lacked vitamins A, B9, B12, and C, and the common bean lacked vitamins A, B12, and C. While farmers recognized the importance of the milpa, they preferred monocultures due to the reduced labor demands of this system. Households that obtained most of their income from off-farm activities had the lowest nutritional self-sufficiency. Enhancing nutritional self-sufficiency through crop diversification has the potential to not only improve the nutrition of subsistence farmers, but also to enhance ecosystem service provision, promote biodiversity conservation and restoration, and improve resilience to climate change.


2020 ◽  
Vol 50 ◽  
Author(s):  
Victor D'Amico-Damião ◽  
Arthur Arrobas Martins Barroso ◽  
Pedro Luis da Costa Aguiar Alves ◽  
Leandro Borges Lemos

ABSTRACT Crop rotation is critical in the management of herbicide-resistant weed species. This study aimed to evaluate the effect of intercropping systems of maize with brachiaria or crotalaria on qualitative and quantitative parameters of the weed seedbank, along the succession of pearl millet, maize and common bean. Moreover, the effect of these crop rotation systems on the selection of specific weed species of the seedbank was also evaluated. The experimental design was randomized blocks, with four replications. The treatments were represented by three cropping systems in succession: pearl millet, single maize, common bean; pearl millet, maize intercropped with brachiaria, common bean; pearl millet, maize intercropped with crotalaria, common bean. The following phytosociological indexes were calculated: density, frequency and relative importance, diversity and equitability. The grain yield of maize and common bean were also quantified. Twenty-three weed species were identified, divided into 12 families, highlighting the Poaceae one, with the most important being Alternanthera tenella, Commelina benghalensis, Eleusine indica and Phyllanthus tenellus. The cropping system with single maize presented a lower density and diversity of weeds, but with a high selection of E. indica. The intercropping systems in the previous crop, as a guarantee of a higher weed diversity, could be use as alternative tools, different from the herbicides, to control weeds and improve the common bean yield. Regarding the weed control in the common bean, Crotalaria spectabilis presented better results in the previous maize-intercropping system than Urochloa ruziziensis.


Plant Disease ◽  
2020 ◽  
Vol 104 (8) ◽  
pp. 2130-2137
Author(s):  
Pamela Paparu ◽  
Amos Acur ◽  
Fred Kato ◽  
Catherine Acam ◽  
Justine Nakibuule ◽  
...  

Over the last 5 years, Southern blight caused by Sclerotium rolfsii Sacc. has superseded root rots caused by pathogens such as Fusarium and Pythium spp. as a major constraint of common bean (Phaseolus vulgaris L.) production in Uganda. Although S. rolfsii is prevalent in all bean-growing regions of Uganda, there is a lack of information about its diversity and pathogenicity to guide the development of effective management strategies. In total, 348 S. rolfsii isolates were obtained from bean fields in seven agroecological zones of Uganda, with the following objectives: to characterize their morphology, based on mycelial growth rate, mycelium texture, and number of sclerotia; and to determine the pathogenicity of 75 selected isolates on five common bean varieties in artificially inoculated soils in a screenhouse. We found that mycelial growth rate and the number of sclerotia produced on artificial media varied among agroecological zones but not within a zone. The five bean varieties tested were found to be susceptible to S. rolfsii, including varieties MLB49-89A and RWR719 that are resistant to Fusarium and Pythium root rots, respectively. Preemergence damping-off ranged between 0 and 100%, and disease severity index ranged between 4.4 and 100%. The widespread and high levels of S. rolfsii virulence on varieties of common bean indicate that management intervention is urgently required to help reduce losses incurred by Ugandan smallholder farmers. [Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .


ISRN Agronomy ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Lindsey D. Thiessen ◽  
Jason E. Woodward

Peanut (Arachis hypogaea L.) is susceptible to diseases caused by numerous soilborne pathogens. In the southwestern United States pathogens including Botrytis cinerea Pers.: Fr., Pythium spp., Rhizoctonia solani Kühn AG-4, Sclerotinia minor Jagger and Sclerotinia sclerotiorum (Lib.) de Bary, Sclerotium rolfsii Sacc., and Verticillium dahliae Kleb. routinely affect peanut yield. This region has an arid climate and peanut development is generally later than in other peanut production areas, hence the time plants are exposed to pathogens is increased. These pathogens cause similar symptoms in the field; therefore, proper diagnosis is needed so that the appropriate management strategies can be implemented.


Author(s):  
Maria da C. S. Carvalho ◽  
Adriano S. Nascente ◽  
Gilvan B. Ferreira ◽  
Celso A. P. Mutadiua ◽  
José E. Denardin

ABSTRACT There is little information about common bean fertilization in African Savannas. The objectives of this study were as follows: i) to evaluate the common bean yield potential in the environmental conditions of Lichinga, Niassa, Mozambique, and ii) to determine the common bean response to phosphorus and potassium fertilization applied together in order to verify whether the interpretation of soil analysis for the Brazilian Cerrado could be adopted for Savanna soils in Mozambique. The experimental design was a randomized block design in a 5 x 4 x 2 factorial arrangement. Treatments consisted of a combination of phosphorus doses (0, 35, 70, 140 and 280 kg ha-1 of P2O5), potassium doses (0, 50 100 and 200 kg ha-1 of K2O), and different growing seasons (2012/2013 and 2013/2014). The field rainfed experiments were conducted in Lichinga city, province of Niassa. Common bean crops presented high productivity potential in rainfed systems in the environmental conditions of Lichinga, Niassa, Mozambique, reaching grain yields of up to 3,600 kg ha-1 depending on the rates of fertilization with phosphorus and potassium. Common beans responded to phosphorus and potassium fertilization despite high contents of these nutrients in the soil, according to the interpretation of soil analysis for the Brazilian Cerrado. Maximum grain yield in the average of two growing seasons was estimated to occur for 239 kg ha-1 of P2O5 and 141 kg ha-1 of K2O, indicating that further calibration studies for P and K are required for this specific region of Mozambique.


Author(s):  
Stefany Silva de Souza ◽  
Pedro Afonso Couto Júnior ◽  
Jordana de Araujo Flôres ◽  
Fábio Luiz Checchio Mingotte ◽  
Leandro Borges Lemos

ABSTRACT The common bean succession to intercropped crops in the no-tillage system is beneficial, especially in the search for sustainability. In addition to the straw production, the intercropping can supply nitrogen (N) to the common bean grown in succession, reducing the use of mineral fertilizer, which is pollutant and has a high cost. The present study aimed to evaluate the response to N fertilization of common bean in succession to maize cropping systems, as well as the viability of these systems in the no-tillage system. The experimental design was randomized blocks, in a split-plot arrangement, with four replicates. The plots consisted of the following systems: maize as a single crop, maize intercropped with brachiaria and maize intercropped with crotalaria. The subplots were five N doses (0 kg ha-1, 50 kg ha-1, 100 kg ha-1, 150 kg ha-1 and 200 kg ha-1), applied as topdressing fertilization in winter common bean, in succession to the maize cropping systems. For the maize cultivation systems, the grain yield and N amount and accumulation in the straw were evaluated. As for the common bean in succession, the grain yield and grain quality attributes were assessed. Although the three cropping systems were viable for maize grain yield, the intercropping of maize with crotalaria led to a higher N accumulation in the straw and a larger quantity of straw dry mass. The increase of the N doses promoted an increase in the grain yield of common bean grown in succession to intercropped maize. Maize intercropped with crotalaria resulted in grains with a higher size and, concerning the grain yield, an equivalent effect to that of a topdressing application of more than 200 kg ha-1 of N was observed for the common bean in succession.


Author(s):  
J.D. Duff ◽  
M.C. Firrell

Brassica biofumigant cover crops are being increasingly considered in vegetable crop rotations as part of an integrated disease management strategy and simply as a cover cropping choice. Nine biofumigant varieties were assessed to see if they could be grown year-round in the Lockyer Valley South East Queensland region, for yield, days to incorporation and glucosinolate concentrations, as well as efficacy against 3 soilborne pathogens; Sclerotinia sclerotiorum, Sclerotium rolfsii and Macrophomina phaseolina. The fastest growing brassica biofumigant was BQ Mulch which reached 25% flowering in 36 and 59 days from planting to incorporation with a summer and winter planting respectively. Nemcon and Nemclear took the longest to incorporation when planted in summer, 101 days and failed to flower, while Caliente, Tillage Radish and Biofum reached 25% flowering and incorporation in 98 days when planted in winter. BQ Mulch produced the least amount of biomass, 30.93 t/ha fresh weight and 2.92 t/ha dry weight with a summer planting. Biofum producing the greatest amount of biomass, 185.76 t/ha fresh weight and 17.34 t/ha dry weight with a summer and winter planting respectively. Most varieties produced more total glucosinolates during summer compared to winter. Caliente produced the highest levels of Total GSLs with 53.47 µmol/g DW in summer compared to 23.78 µmol/g DW in winter. This was reflected in their efficacy against the soilborne pathogens. Caliente and Mustclean were more efficacious at controlling Macrophomina and Sclerotinia in summer compared to winter while all varieties were more efficacious at controlling Sclerotinia with a summer planting compared to a winter planting.


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