Copyright © 2014, American-Eurasian Network for Scientific Information publisher American-Eurasian Journal of Sustainable Agriculture ISSN: 1995-0748 JOURNAL home page: http://www.aensiweb.com/aejsa.html 2014 Special ; 8(7): pages 1-7. Published Online 2014 February 30. Research Article Corresponding Author: Chong Khim Phin, Sustainable Palm Oil Research unit (SPOR), School of Science and Technology, Universiti Malaysia Sabah. Tel: 60-88320000 ext: 5571; Fax:+60-88435324; E-mail: chongkp@ums.edu.my Combination of Biological Agents in Suppressing Colonization of Ganoderma boninense of Basal Stem rot Arnnyitte Alexander and Chong Khim Phin Sustainable Palm Oil Research unit (SPOR), School of Science and Technology, Universiti Malaysia Sabah Received: 25 June 2014; Received: 8July 2014; Accepted: 10 August May 2014; Available online: 30 August 2014 © 2014 AENSI PUBLISHER All rights reserved ABSTRACT Basal Stem Rot (BSR) is the most destructive disease of oil palm caused by Ganoderma boninense. With no remedy to date, a study on the potential of microbes in suppressing colonization of G. boninense was designated. Three products contain combinations of Biological Control Agents (BCAs), (designated TR1, TR2 and TR3) to suppress the growth of Ganoderma boninense was investigated in this research. To understand the ability of the treatments in suppressing the BSR disease incidence, assessments in nursery and field trial were conducted. The results from both trials showed that TR 1, TR 2 and TR 3 were able to reduce the colonization of G. boninense based on the reduction of ergosterol content and Disease Incidence (DI) compared to untreated control. However, in nursery trial, treated seedlings showed an increment in DI after four months with lesser colonization based on the ergosterol quantities. Meanwhile, assessment in the field trial showed that TR 1 and TR 3 had significantly reduced the DI down to 12% and 24% and the amount of ergosterol to 0.663 μg g -1 and 1.817 μg g -1 of trunk tissues respectively. The use of BCAs could offer an alternative to control the Ganoderma infection in oil palm. Keywords: oil palm, Ganoderma boninense , Biological Control Agents, Ergosterol INTRODUCTION One of the major diseases contributes to huge losses in oil palm industry is the Basal Stem Rot (BSR) which caused by Ganoderma boninense. In earlier years, this disease was reported to affect only mature palms aged 30 years and above, however, infected palms as young as 12-24 months after planting was also detected later [20]. A number of different strategies has been employed to manage the disease but none has shown satisfactory effect. Some recent control measures to overcome this disease are now focused on the use of biological control agents (BCA). Several promising antagonist BCAs such as Trichoderma spp. [19,22], Penicillium spp. [8], Burkholderia spp. [18], Bacillus spp. [21] and Pseudomonas spp. [4] have shown high efficacy in controlling the growth and infection of Ganoderma boninense both in nursery and field. Several mechanisms have been suggested to be responsible for the effects of these BCAs, these include competition for space and nutrients, mycoparasitism, metabolite production, antibiosis and inducing plant systemic resistance [26]. However, effective suppression of plant disease by BCAs is largely affected by environment conditions [10]. Application of single bioagent can have limitation with regard to its consistency and efficacy in different environments. Therefore, more emphasis is laid on the combined use of biocontrol agents, for improved disease control and also to overcome the inconsistent performance of the BCA. Introduction of one or more BCAs to the soil, assuming that each has different ecological requirements, may facilitate disease control without affecting the efficacy of a single organism under diverse conditions, and may result in increased control consistency [10]. Cocktails of biocontrol agents may have advantages of broad spectrum activity, enhancing the efficacy and reliability of the biological control and they communicate with each other to maximize biocontrol efficacy. Therefore, in the present study, combination of several microbes in three microbial based products was evaluated for