Basal stem rot due to a fungal pathogen, Ganoderma boninense, is one of the most devastating diseases in oil palm throughout the major palm oil producer countries. This study investigated the potential of polypore fungi as biological control agents against pathogenic G. boninense in oil palm. In vitro antagonistic screening of selected non-pathogenic polypore fungi was performed. Based on in planta fungi inoculation on oil palm seedlings, eight of the 21 fungi isolates tested (GL01, GL01, RDC06, RDC24, SRP11, SRP12, SRP17, and SRP18) were non-pathogenic. In vitro antagonistic assays against G. boninense revealed that the percentage inhibition of radial growth (PIRG) in dual culture assay for SRP11 (69.7%), SRP17 (67.3%), and SRP18 (72.7%) was relatively high. Percentage inhibition of diameter growth (PIDG) in volatile organic compounds (VOCs) in dual plate assay of SRP11, SRP17, and SRP18 isolates were 43.2%, 51.6%, and 52.1%, respectively. Molecular identification using the internal transcribed spacer gene sequences of SRP11, SRP17, and SRP18 isolates revealed that they were Fomes sp., Trametes elegans, and Trametes lactinea, respectively.

The oyster mushroom (Pleurotus species) is a popular and widely cultivated edible mushroom that can be found worldwide, including in Malaysia. However, its local production is unable to fulfil the market demand, partly due to the limited availability of rubber wood sawdust (RWS) as the conventional cultivation substrate. Furthermore, the palm oil industry in Malaysia generates large volumes of organic by-products that have caused environmental concerns. Therefore, the potential utilisation of oil palm waste-based substrates in order to develop a substitute RWS for Pleurotus ostreatus mushroom production is evaluated in this study, based on their agronomic performance and nutritional properties. Empty fruit bunches (EFBs), oil palm fronds (OPFs), and oil palm trunks (OPTs) were used to formulate the substrates. The control used was 100% RWS. Generally, 100% EFB showed a better agronomic performance, and mushroom growth was 1.9 times faster compared to the control, with a comparable mushroom yield. The crude protein and beta glucan content of mushrooms grown on oil palm by-product-formulated substrates were significantly higher than those grown using the control. Additionally, the number of fruiting bodies, crude protein, and beta glucan content of the mushrooms were positively correlated with potassium in the substrate. Therefore, 100% EFB could be used as a potential substitute for RWS for the cultivation and production of P. ostreatus.

| Sweet corn ( Zea mays L. var. saccharata ) is an important palatable grain grown for human consumption, for both fresh and processed foods. In this study, efficacy of Azolla pinnata aqueous extract on the growth and yield of sweet corn through foliar application was evaluated. Independent variables were application rates of urea (120, 110, 100, 90, 80, and 0 kg ha -1 ) and aqueous Azolla extract (AE i.e. 0, 10, 20, 30, 40, and 100%, v/v). Common variables were 60 kg/ha triple superphosphate (TSP), 90 kg/ha muriate of potash (MOP), and watering. The dependent variables were growth and yield parameters of sweet corn. One-way ANOVA was used for analysis, where significant differences between treatments were determined using the Least Significant Difference (LSD) Test (SAS 9.4 software). Results revealed significant differences (p <0.05) in sweet corn that received AE foliar spray in plant height (p = 0.0098), stem diameter (p = 0.0419), leaf area (p = 0.0364), cob length (p = 0.0077), and number of grains per cob (p = 0.0207) compared to the control plant received an optimal rate of 120 kg ha -1 urea without AE. No significant differences were recorded for chlorophyll content, cob fresh weight, and weight of 100 grains. It is found that sweet corn received high N with the lowest AE (110 kg ha -1 urea + 10% AE) enhanced vegetative growth in plant height, stem diameter, leaf area, cob length, and grain yield. In sum, AE of Azolla is a potential and environmentally friendly organic fertilizer that is easy to grow, prepare, and apply by growers, in compensation for the reduction of 10 kg ha -1 urea used in sweet corn cultivation.

Plant growth-promoting bacteria are gaining significant attention as promising biofertilizers. However, the inconsistency between in vitro plant growth-promoting traits and actual field performance remains a challenge, driven partly by a limited understanding of in situ colonization. This study characterized the colonization patterns of Citrobacter sedlakii CESi7, a novel plant growth-promoting bacterium, isolated from oil palm waste compost, during Brassica rapa cultivation. The in situ behavior of CESi7 was observed in both sterilized medium and non-sterilized soil using fluorescence in situ hybridization with a strain-targeting probe. The results revealed that CESi7 can establish both epiphytic and endophytic populations that transiently colonize roots. In a sterilized medium, CESi7 was widely distributed throughout the root tissues. Conversely, in non-sterilized soil, the bacterium formed dense aggregates specifically at the root tips. This study provides direct microscopic evidence of the colonization strategy of CESi7, offering crucial insights for its development as an effective biofertilizer.