Evaluating the Efficacy of Chitosan and Nanochitosan in Controlling the Fungal Causal Agent of Pink Ear Rot Disease in Maize Fusarium verticillioides

Zea mays (maize) is a crop of global importance with numerous applications, including livestock feed, human-grade food items, and industrial biofuels. Maize crop is susceptible to many fungal diseases that affect yield and quality and are caused by pathogens such as Fusarium and Aspergillus. Fusarium is one of the most economically significant maize fungal diseases due to its impact on yield and toxigenicity. Five fungal isolates responsible for pink ear rot in maize were collected from various regions in Egypt and identified as Fusarium verticillioides (FV) by the Mycology Research and Disease Survey Department at the Plant Pathology Institute, ARC, Giza, Egypt. The study employed ITS sequencing to compare these isolates with registered strains in GenBank, revealing sequence identities ranging from 95.16% to 96.15%. The FV-N isolate exhibited the highest similarity (96.15%) to a strain from China, while FV-K and FV-T showed 95.38% similarity. FV-M had a similarity of 95.67%, and FV-B exhibited 95.16% similarity to an Indian isolate. All isolates produced 500 bp DNA amplicons consistent with standard F. verticillioides. The pathogenicity of the five isolates was evaluated on maize (cv. Yellow single cross hybrid 168), with FV-N displaying the highest percentage disease incidence “PDI%” (88.9%) and disease severity percentage “PDS%” (47.6%). Additionally, a dynamic light scattering technique was used to assess the size distribution and stability of synthesized chitosan nanoparticles, revealing sizes predominantly between 67.2 to 150.1 nm.