PATHOGENICITY OF Macrophomina SPECIES COLLECTED FROM WEEDS IN COWPEA

Rui Sales Júnior,Andréia Mitsa Paiva Negreiros,Márcia Michelle De Queiroz Ambrósio,Alfredo Nogueira Da Silva Neto,Thomaz Rauan Rodrigues Gomes,Josep Armengol

doi:10.1590/1983-21252020v33n212rc

Rui Sales Júnior, Andréia Mitsa Paiva Negreiros + Show 4 more

Open Access

https://doi.org/10.1590/1983-21252020v33n212rc

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Abstract

ABSTRACT Charcoal rot caused by Macrophomina phaseolina is a major cowpea disease causing substantial losses to growers. In the semi-arid region of Brazil, cowpea is one of the most widely used alternatives for crop rotation during the off-season of melon. This favors Macrophomina multiplication because both crops are hosts of this pathogen. The objective of this study was to verify the pathogenicity of Macrophomina phaseolina and M. pseudophaseolina on cowpea. The Macrophomina spp. isolates used were obtained from the roots of Trianthema portulacastrum and Boerhavia diffusa, weed species prevalent in melon production areas in North-east Brazilian. The experiment was carried out in a greenhouse. Cowpea plants cv. ‘Paulistinha’ were inoculated with 30 M. phaseolina isolates, 30 M. pseudophaseolina isolates and a reference isolate of M. phaseolina obtained from cowpea roots. All Macrophomina isolates were able to cause disease on cowpea and there were no statistical differences between both Macrophomina species regarding disease incidence and severity. Moreover, 65.2 and 100.0% of the M. phaseolina isolates, and 56.2 and 92.8% of the M. pseudophaseolina isolates, obtained from T. portulacastrum and B. diffusa, respectively, were as severe to cowpea as the M. phaseolina reference isolate from cowpea. These results emphasize the need to establish management practices aiming to control T. portucalastrum and B. diffusa from cowpea production areas, as they can act as potential sources of inoculum and survival for Macrophomina spp.

Highlights

Cowpea (Vigna unguiculata [L.] Walp.) is one of the main legumes cultivated in semi-arid regions of African countries, with 95.9% of world production (7.1 million tons) (FAOSTAT, 2019)
World production is underestimated because countries such as Brazil and India do not have separate production data between cowpea and common bean (Phaseolus vulgaris L.) (DAMASCENO-SILVA; ROCHA; MENEZESJÚNIOR, 2016)
This study aims to verify the pathogenicity of M. phaseolina and M. pseudophaseolina isolates obtained from roots of the weed species T. portulacastrum and B. diffusa on cowpea

Summary

Introduction

Cowpea (Vigna unguiculata [L.] Walp.) is one of the main legumes cultivated in semi-arid regions of African countries, with 95.9% of world production (7.1 million tons) (FAOSTAT, 2019). In Brazil, cowpea production is concentrated mainly in the North- east and North Regions, with increasing progress in the Midwest region. This crop is considered one of the main protein sources of human food, and an important generator of employment and income in the growing regions (ROCHA et al, 2009; DAMASCENO-SILVA; ROCHA; MENEZES-JÚNIOR, 2016). The importance of cowpea is due to the possibility of being cultivated by small farmers in family farms under irrigated and rainfed conditions, due to its easy management and low production costs, playing an important socioeconomic role (RAMOS et al, 2012; DAMASCENO-SILVA; ROCHA; MENEZESJÚNIOR, 2016).

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