Biostimulants such as silicate (SiO₃²⁻) compounds and antagonistic bacteria can alter soil microbial communities and enhance plant resistance to the pathogens and Fusarium oxysporum f. sp. cubense (FOC), the causal agent of Fusarium wilt disease in bananas. A study was conducted to investigate the biostimulating effects of SiO₃²⁻ compounds and antagonistic bacteria on plant growth and resistance of the banana to Fusarium wilt disease. Two separate experiments with a similar experimental setup were conducted at the University of Putra Malaysia (UPM), Selangor. Both experiments were arranged in a split-plot randomized complete block design (RCBD) with four replicates. SiO₃²⁻ compounds were prepared at a constant concentration of 1%. Potassium silicate (K₂SiO₃) was applied on soil uninoculated with FOC, and sodium silicate (Na₂SiO₃) was applied to FOC-contaminated soil before integrating with antagonistic bacteria; without Bacillus spp. ((0B)—control), Bacillus subtilis (BS), and Bacillus thuringiensis (BT). Four levels of application volume of SiO₃²⁻ compounds [0, 20, 40, 60 mL) were used. Results showed that the integration of SiO₃²⁻ compounds with BS (10⁸ CFU mL⁻¹) enhanced the physiological growth performance of bananas. Soil application of 28.86 mL of K₂SiO₃ with BS enhanced the height of the pseudo-stem by 27.91 cm. Application of Na₂SiO₃ and BS significantly reduced the Fusarium wilt incidence in bananas by 56.25%. However, it was recommended that infected roots of bananas should be treated with 17.36 mL of Na₂SiO₃ with BS to stimulate better growth performance.

A field investigation was conducted in a Fusarium-infected area to evaluate the effectiveness of silicate compounds with antagonist bacteria on morpho-physiological growth performance in bananas. The roots of banana plants were treated by drenching the soil with four different treatments: control (without any treatment), CBZ (Carbendazim fungicide alone), SS + BS (integration sodium silicate with Bacillus subtilis), and CBZ + SS + BS (integration CBZ, SS, and BS). All treatments were arranged in a randomized complete block design with four replications. The results confirm that plant height, pseudo-stem diameter, and canopy diameter markedly increased from weeks 2 to 10 after transplantation. Amendment with these elements induced a higher total chlorophyll content, which contributed to the increased rate of leaf gas exchange and biochemical changes for controlling Fusarium wilt disease infection. From these findings, the CBZ + SS + BS application in the farm had significantly reduced disease incidence by 16.07% and disease severity by 14.28%. The same treatment achieved the greatest disease reduction by 63.05%. Therefore, the integration between CBZ + SS + BS had good significant effects in controlling Fusarium wilt disease and enhanced the morpho-physiological growth performance with an average yield production of about 24.72 kg per fruit bunch.

The amendment of soils with silicate (Si) compounds is essential to promote growth performance and control Fusarium wilt disease in bananas. Two successive greenhouse trials were conducted at the experimental farm of the University of Putra Malaysia. The treatments were arranged in split plots using a randomized complete block design (RCBD) with four replicates to investigate the effects of Si compounds and application frequency on controlling FOC. Si compounds were used at a constant concentration of 0.1%: T0 (control), T1 (13% SiO₂:20% K₂O), T2 (26.6% SiO₂:13.4% K₂O) and T3 (36.2% SiO₂:17% Na₂O). There were three application frequencies by day intervals (DI): 0DI (without any application), 7DI (12× within 12 weeks after transplanting (WAT)), 15DI (6× within 12 WAT) and 30DI (3× within 12 WAT). From these findings, we observed that the photosynthesis rate started to increase from 10.6 to 19.4 µmol CO₂ m⁻²s⁻¹, when the total chlorophyll content started to increase from 3.85 to 7.61 mgcm⁻². The transpiration rate started to increase from a value of 1.94 to 4.31 mmol H₂O m⁻²s⁻¹, when the stomata conductance started to increase from 0.237 to 0.958 mmol m⁻²s⁻¹. The proline content started to increase from 22.89 to 55.07 µmg⁻¹, when the relative water content started to increase from 42.92 to 83.57%.