Biological control of Sclerotium rolfsii on tomato seedlings using Bacillus spp. consortium

Abstract

The Sclerotium rolfsii which widely distributed soil-borne plant pathogen, causes many economically important crops severely reduce their yield at worldwide extend, including tomato and are very difficult to control due to its sclerotia. The beneficial plant-microbe interactions play crucial roles in protection against large number of plant pathogens causing disease. Our previous research had screened 9 Bacillus spp. strains which had ability to control R. syzigii subsp. indonesiensis and promote growth and yield of solanaceous plants. Those strains were Bacillus cereus AGBE 1.2 TL, Bacillus toyonensis AGB E 2.1 TL, Bacillus cereus SLB E 1.1 SN, Bacillus cereus SLB E 1.1 AP, Bacillus pseudomycoides SLB E 3.1 AP, Bacillus cereus SLB E 1.1 BB, Bacillus cereus SLB E 2.1 BB, Bacillus thuringiensis SLB E 2.3 BB, and Bacillus cereus SLB E 3.1 BB. Our current study objective was to develop the best consortium to control S. rolfsii and promote growth of S. rolfsii seedlings. The research designed in experimental methods and was arranged in a completely randomized design with 7 treatments and triplications. The methods done were compatibility assay of the Bacillus strains, development of consortium based from the compatibility, and consortium assay to control S. rolfsii and promote growth of tomato seedlings. The result showed, out of the 6 compatible consortiums, consortium A4 consists of Bacillus strain AGBE 1.2 TL, SLBE 3.1 AP, SLBE 2.1 BB and SLBE 3.1 BB were shown to be the best to control S. rolfsii on tomato seedlings with 85.00% of the seedlings were shown no symptoms. The consortium also had the best ability to promote growth of tomato seedlings up to 25.00% compared with control.