Controlling Basal Stem Rot in Oil Palm Plantations by Applying Arbuscular Mycorrhizal Fungi and Trichoderma Spp.

Biological agents are critical in the management of major diseases in oil palm plantations. The potential of arbuscular mycorrhiza fungi (AMF) and Trichoderma spp. to control basal stem rot disease was investigated in this study. Three-month-old seedlings treated with AMF since the beginning of planting demonstrated AMF colonization of the roots. With a 25 gram AMF treatment in the main nursery, AMF colonization increased by 85.99% in TBM-1 (the 1-year immature plant). In TBM-2, AMF colonization increased by 86.00-97.33% (2-year immature plant). All of the treatments started with 30 grams of Trichoderma spp. applied at the start of pre-nursery planting. Root colonization and the number of spores in the root rhizosphere in TBM-2 had a strong relationship (2-year immature plant). AMF inoculation had a significant impact on root colonization and spore number response. According to this study, the application of 25 grams of AMF in the pre-nursery and main nursery, as well as repeated additions at planting, were found to be effective in controlling attacks of basal stem rot disease through early prevention strategies. Keywords: biological control agent, arbuscular mycorrhiza fungi (AMF), Trichoderma spp. oil pal

Biological Control of Postharvest Diseases by Microbial Antagonists

The postharvest phase has been considered a very suitable environment for successful application of biological control agents (BCAs), since the first work on the biological control of brown rot disease of stone fruit was reported by Pusey and Wilson [1]. Sure enough, the conditions of constant temperature and high humidity seem to offer more chances to BCAs, increasing their antifungal activity [2]. BCAs are living organisms and act following different antagonistic strategies depending on pathogens, host and environment. Knowledge of their modes of action is therefore essential to enhance their viability and increase their potentiality in disease control. In general, antagonists used for biocontrol of postharvest diseases are yeasts and bacteria, and to a lesser extent fungi, and they have been widely reviewed [3\u20137]. Antagonists can display a wide range of modes of action, at different stages of their activity, relating to different hosts, pathogens; sometimes-different modes act simultaneously, and it is therefore difficult to establish which individual mechanism has contributed to a specific antifungal action. Considerable information is available with respect to their efficacy, their application under storage conditions, and their mixture with safe substances or according to the formulation. However, the mechanisms by which BCAs exert their activity against pathogens have not yet been fully elucidated [5] and sometimes, in order to achieve maximum effectiveness in postharvest phase, were combined with physical and chemical methods including heat treatments, gamma or UV-C irradiation, and controlled atmosphere (CA). The bottleneck of the biocontrol matter remains the BCAs formulation often done in association with private companies, due to the high costs of production and the regulatory barriers to BCAs registration in different countries that often do not encourage their dissemination. Also, a formulation often could reduce the activity of antagonists with respect to the fresh cells [2]

Biological Control of Postharvest Diseases by Microbial Antagonists

The postharvest phase has been considered a very suitable environment for successful application of biological control agents (BCAs), since the first work on the biological control of brown rot disease of stone fruit was reported by Pusey and Wilson [1]. Sure enough, the conditions of constant temperature and high humidity seem to offer more chances to BCAs, increasing their antifungal activity [2]. BCAs are living organisms and act following different antagonistic strategies depending on pathogens, host and environment. Knowledge of their modes of action is therefore essential to enhance their viability and increase their potentiality in disease control. In general, antagonists used for biocontrol of postharvest diseases are yeasts and bacteria, and to a lesser extent fungi, and they have been widely reviewed [3–7]. Antagonists can display a wide range of modes of action, at different stages of their activity, relating to different hosts, pathogens; sometimes-different modes act simultaneously, and it is therefore difficult to establish which individual mechanism has contributed to a specific antifungal action. Considerable information is available with respect to their efficacy, their application under storage conditions, and their mixture with safe substances or according to the formulation. However, the mechanisms by which BCAs exert their activity against pathogens have not yet been fully elucidated [5] and sometimes, in order to achieve maximum effectiveness in postharvest phase, were combined with physical and chemical methods including heat treatments, gamma or UV-C irradiation, and controlled atmosphere (CA). The bottleneck of the biocontrol matter remains the BCAs formulation often done in association with private companies, due to the high costs of production and the regulatory barriers to BCAs registration in different countries that often do not encourage their dissemination. Also, a formulation often could reduce the activity of antagonists with respect to the fresh cells [2]