ecmn | boatload - 8/9/2025 08:21
5 years ago, the universities were warning us this would happen if we overused fungicide.
I may say a lot of strange sounding things and go against the grain a little bit. But everything I say I have always backed up with research.
1. FRAC (Fungicide Resistance Action Committee) — central guidance on modes of action, resistance lists, and stewardship recommendations.
Takeaway: resistance is predictable; stewardship is necessary to extend product life.
2. University of Illinois Extension — “You don’t know what you have till it’s gone” (blog on frogeye leaf spot & QoI resistance).
Takeaway: QoI (strobilurin) resistance in soybean pathogens was found within a decade of wide use — resistance spreads fast.
3. Purdue Extension — Fungicide efficacy & timing for corn (BP-160) (extension factsheet).
Takeaway: Extension efficacy tables and timing guidance show where fungicides actually help — and where they don’t.
4. University of Wisconsin Extension — “Fungicide resistance management” (A3878 PDF).
Takeaway: UW extension has practical resistance management guidance — rotate chemistries, don’t rely on repeat applications.
5. Meta-analysis of foliar fungicide yield response (open access, PMC).
Takeaway: Yield responses to foliar fungicides are highly variable; many trials show little to no benefit when disease pressure is low.
6. APS/Phytopathology reviews on fungicide resistance mechanisms (recent reviews).
Takeaway: Molecular studies show multiple resistance mechanisms emerging — resistance isn’t hypothetical, it’s happening and evolving.
7. Research: QoI-resistant Cercospora sojina distribution (PDIS paper).
Takeaway: QoI-resistant frogeye leaf spot is widespread in some states and shows cross-resistance across QoI products.
8. Extension/meta commentary from UMN — long-term studies on “insurance” fungicide use (blog summary).
Takeaway: Long-term data show fungicides can pay in some environments, but blanket “insurance” sprays aren’t a universal solution.
9. Review on resistance management & integrated strategies (Plant Pathology/BSPP review).
Takeaway: Best practice is integrated disease management — fungicides are a tool, not the long-term cure; sound crop/soil management matters.
10. Meta-study on fungicide effects on soil microbes and respiration (recent meta-analysis).
Takeaway: Repeated fungicide use can change soil microbial activity — another reason broad reliance is risky for long-term field health. |
Southern rust
