Biological Control of the Charcoal Rot Disease of Pepper Caused by Macrophomina phaseolina

(Safaa Neamat Hussein and Thekra Atta Ibrahim)

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Abstract

The charcoal rot disease, caused by Macrophomina phaseolina (Mp), is a harmful plant diseases that affect a wide range of the plant species. Recently, economic losses were observed in various growing area of pepper. This study aimed to isolate, identify the causing agent of the disease in various pepper fields in middle and south Iraq, and control it biologically. Result of isolation indicated the presence of number of the fungi dominated by Mp. The later appeared in all the samples with frequency of 53.23%. Isolates of the Mp showed varied in their pathogenicity on pepper seeds in vitro. Isolate Mbs-3reduced seed germination to 12% compared to 100% for the control. Evaluation of the antifungal treatments was conducted for the rhizobacteria isolates of Azotobacter chroococcur (Ac), Azospirillum brasilense (Ab), Enterobacter cloacae(Ec), Pseudomonas putida (Pp) and Serratia odorifera (So) against the pathogen in vitro. All bio-agents significantly reduced the growth of the pathogen on the potato dextrose agar (PDA). Treatment of the penta-inoculum of Ac+Ab+Ec+Pp+So was superior which exhibited 100% percentage of inhibition compared to the control after 7 days. Under greenhouse conditions, all the bio-agents significantly increased the percent of the seed germination, which ranged between 87.5-100.0% compared to the negative control, which was 60.0%. Treatment of the penta-inoculum was superior in controlling the disease as it exhibited 0% percentage of disease incidence and severity compared to negative control, which were 97.5%, 74.7% respectively. All bio-agents significantly increased growth criteria represented by dry weight of the plants. Keywords: Bio-agents, Charcoal rot, Green house infection, In vitro infection.
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