Greenhouse evaluation of Bacillus subtilis AP-01 and Trichoderma harzianum AP-001 in controlling tobacco diseases

Abstract

Two biological control agents, Bacillus subtilis AP-01 (Larminar TM ) and Trichoderma harzianum AP-001 (Trisan TM ) alone or/in combination were investigated in controlling three tobacco diseases, including bacterial wilt (Ralstonia solanacearum), damping-off (Pythium aphanidermatum), and frogeye leaf spot (Cercospora nicotiana). Tests were performed in greenhouse by soil sterilization prior to inoculation of the pathogens. Bacterial-wilt and damping off pathogens were drenched first and followed with the biological control agents and for comparison purposes, two chemical fungicides. But for frogeye leaf spot, which is an airborne fungus, a spraying procedure for every treatment including a chemical fungicide was applied instead of drenching. Results showed that neither B. subtilis AP-01 nor T. harzianum AP-001 alone could control the bacterial wilt, but when combined, their controlling capabilities were as effective as a chemical treatment. These results were also similar for damping-off disease when used in combination. In addition, the combined B. subtilis AP-01 and T. harzianum AP-001 resulted in a good frogeye leaf spot control, which was not significantly different from the chemical treatment.

Application of microorganisms, alone or in combination, to control postbloom fruit drop in citrus

“…On the other hand, Roberts et al (2005) studied different isolates of Trichoderma and bacteria such as Serratia marcescens, Burkholderia ambifaria, and Burkholderia cepacia for biocontrol of different fungal diseases caused by Rhizoctonia solani and Pythium ultimum in cucumber and found that the combinations of biocontrol agents were more effective when compared to applications of the agents alone. The same result was found by Maketon et al (2008), which showed that neither B. subtilis nor T. harzianum alone could control Ralstonia solanacearum, causal agent of bacterial wilt in tobacco, but when combined, they provided control levels similar to the chemical treatment.…”

Bacillus-Based Biological Control of Plant Diseases

“…(Sivakumar et al, 2007) Mango Oidium mangiferae (Nofal & Haggag, 2006) Mellon Podosphaera fusca (Romero et al, 2007b) Mustard Alternaria brassicae (Sharma & Sharma, 2008) Nectarine Monilinia laxa (Casals et al, 2010) Oilseed rape Sclerotinia sclerotiorum (Hu et (Salerno & Sagardoy, 2003) Tobacco R. solanacearum (Maketon et al, 2008) Tomato Xanthomonas euvesicatoria Xanthomonas perforans (Roberts et al, 2008) Nematodes Tomato Meloidogyne (Araújo & Marchesi, 2009) (Siddiqui & Futai, 2009) …”

Efficacy of the bioagents Bacillus isolates and Trichoderma spp. in the control of wilt/root-rot disease in chickpea

“…a Severity of root necrosis was assessed on a scale of 0-10 according to the following scale, 0 ¼ 0 per cent, 1 ¼ 1-10 per cent, and 10 ¼ 91-100 per cent; b Rf (the reproduction index) ¼ final population density divided by initial population density; c DII (the disease intensity index) ¼ incidence of foliar symptoms × severity data/4, after 90days of inoculation combination of the BCA was more effective than either used alone in reducing disease progress and/or promoting the plant growth. As reported by Duffy et al (1996), Larkin andFravel (1998), Howell (2003) and Maketon et al (2008) the use of combination of multiple antagonistic organisms may provide improved disease control over the use of single organism. They enhance the level and consistency of control by providing multiple mechanisms of action, more stable rhizosphere community, and are effective over a wider range of environmental conditions.…”

“…The findings of Maketon et al (2008) showed that neither B. subtilis AP-01 nor T. harzianum AP-001 alone could control the bacterial wilt, damping-off and frogeye leaf spot of tobacco diseases, but when combined, their controlling capabilities increased. Monte (2001) explained this finding as a result of augmentation of levels of inhibitory compounds, which was not seen when either antagonism was applied alone.…”