Ask a Master Gardener: Using Fungicides Effectively (Use Less, Lose Fewer Plants)
- Jennifer McDonald
- 18 hours ago
- 3 min read
By: Jacob Kelley, Extension Agent (Commercial Horticulture), Alabama Cooperative Extension System Jacob.kelley@auburn.edu | www.mobilecountymastergardeners.org
When I moved to Mobile six years ago, I assumed it would be like the rest of the Southeast: hot, humid, buggy, and occasionally soggy. I was wrong. Mobile may be one of the toughest places in the country to grow plants, and not because we lack enthusiasm. We average nearly 70 inches of rain a year (in the top five wettest U.S. cities), and much of it arrives as wind-driven sheets that turn gardens into splash zones.
Days like today (I’m writing this in the middle of a storm), spread plant diseases and insects around like glitter: once it’s out there, you’ll find it everywhere. Even “tough” native plants feel the pressure. And stressed plants (from poor watering, nutrition, or soil conditions) are easier targets for pathogens and insects. It’s a dog-eat-dog world out there for us and our plants…at least we can move.
Rule #1 for preventing plant disease: keep plants as stress-free as possible. Start with the basics: consistent watering, appropriate fertilizer, and the right soil pH. Soil pH is a big deal because it affects how well plants can take up nutrients. The good news: finding your pH is easy. You can pick up a soil test kit at your county Extension office for free, and get the results for about $10, and we’ll help you sample correctly and make sense of the results. We’re a research-based resource in a world full of “my cousin said…” advice, and yes, our help is free.
Even with perfect care, our climate keeps disease pressure high, so we scout. About once a week, take a slow lap through your yard. Check older leaves, new growth, and especially the undersides. Peek into plant “armpits” (those little crotches where stems meet), plus any cracks and crevices where trouble likes to hide. If you never look for problems, they won’t exist…until they really, really do.
That brings us to fungicides, often a Mobile gardener’s best friend, if used correctly. The key idea: most fungicides are protectants, not cures. They work more like wax on a car than like antibiotics. You apply them before conditions favor disease (often before a rainy stretch), and they help prevent spores from getting established. They can slow an outbreak and reduce spread, but they rarely “erase” an infection after it’s taken hold. Even a basic copper fungicide on an appropriate schedule can be better than doing nothing, but timing and consistency matter.
Before you buy every fungicide on the shelf, figure out what you’re actually up against. Not all fungicides work on all diseases, and the “best” option depends on the plant and the problem, so read fungicide labels and learn a little about the usual suspects in your landscape.
Safe fungicide use starts with the label. Follow directions for mixing, use sites, re-entry intervals, and required PPE. Mix and apply outdoors, avoiding windy days to prevent drift, and keep children, pets, and bystanders away until sprays dry (or for the full re-entry period). Store products in original, labeled containers, tightly closed and locked in a cool, dry place away from food, feed, or seed. Dispose of leftovers and containers as directed on the label.
Our web site (aces.edu) has plenty of research-based info (use the search bar), and your local Extension office can help you match the right tool to the job and take the guesswork out of it. We’re here to help you save time, money, and a few gray hairs. To find the helpers, call Mobile County Extension at 251-574-8445 or Baldwin County Extension at 251-937-7176 or the Master Gardener Helpline at 877-252-4769.
Extension Agent Jacob Kelley helps local growers solve disease issues and produce a healthy crop
