Maize ear rot, originally caused by Fusarium verticillioides, poses a serious risk to yield grain quality and food safety because of the associated mycotoxins. Field surveys in 2019, Fusarium spp., Aspergillus flavus, A. niger, and Penicillium spp. were the most prevalent pathogens as 98.2, 98.6, 98.6, and 76.0%. The Balady White cultivar was the most susceptible ones in disease incidence (DI); 89.9–91.8% and disease severity (DS); 51.3–70.9%, while SC10 White displayed the highest resistance (DI; 53.6–63.9% and DS; 40.6–50.7%). A total of 54 fungal isolates were confirmed by PCR as the dominant pathogens F. verticillioides and A. flavus via amplification of their internal transcribed spacer (ITS) regions. Ridomil (200 ppm) was the most effective for suppressing fungal growth and reducing DS in in vitro and greenhouse experiments. Bacillus subtilis (9 × 10⁸ CFU/mL) and clove oil (3% v/v) produced comparable levels of DS and DI that dropped from 41.8 to 5.3% and to 7.9%, respectively under artificial infection (AI). Also, B. subtilis and clove oil increased Polyphenol oxidase (PPO) 0.198 and 0.164 unit mg⁻¹ protein min⁻¹, and Catalase (CAT) 268.59 and 169.69 µmol H2O2 min⁻¹, and improved grain quality by preserving oil, protein, carbohydrate contents and increasing phenolic compound accumulation (378.51 mg) especially under AI. Importantly, both treatments significantly reduced fumonisin contamination and B. subtilis achieving the lowest level (123.56 ppb/kg) compared with 3833.8 ppb/kg for control. Overall, these findings position B. subtilis and clove oil as promising eco-friendly alternatives to chemical fungicides for managing maize ear rot, enhancing resistance, and improving grain safety and quality.
Hamden et al. (Tue,) studied this question.