Farm advice wanted: a fungus that keeps returning after treatment on a 3-hectare plot

I farm 3 hectares of maize in Victoria. This season I'm dealing with a fungus that keeps returning after treatment. I've tried what the local suppliers recommended, but results aren't improving. I'm looking for an agronomist or experienced grower who can look at photos, soil-test results and my planting plan, and advise on what to change. A 30-minute call or exchange of messages would be fantastic. I'm happy to share photos and a soil test. I'm using only what I can afford, so low-cost suggestions are best. I'll share how it goes - and what worked - to help others in the community. Please ask me anything in the questions section. I'll answer honestly and quickly.