Fungal disease on fruit trees is common because a tree stays in the same spot for decades, accumulating the same pruning wounds, bark injuries, and soil-borne spores year after year. Its flowers, leaves, and ripening fruit all give fungi something to feed on. Most infections follow the same pattern: spores already living in the yard take hold once the tree is stressed or the weather stays wet through bloom.
Diseases to Watch For
- Apple Scab — Caused by the fungus Venturia inaequalis. Olive-green spots on leaves in spring; a bad case browns and drops the foliage and leaves raised black spots on the fruit. Scab-resistant varieties (Liberty, Freedom, Enterprise) sidestep the problem almost entirely.
- Pear Scab — The pear-tree version: velvety olive-green spots that distort the fruit and cause early drop.
- Powdery Mildew — A white, powdery coating across the leaf surface, usually starting on new growth. Shows up on apple, plum, and peach trees.
- Brown Rot — Small brown spots on fruit that spread fast, especially on stone fruit like plum, peach, and cherry.Peach
- Leaf Curl — Leaves emerge reddish and puckered a couple weeks after budbreak, then curl, yellow, and drop early. Repeated years of it will weaken the tree.
- Rust — Orange or rust-colored pustules on the underside of leaves.
- Oak Root Fungus (Armillaria) — A white, fan-shaped mat between bark and wood at the root/crown line. Kills slowly, thinning the canopy before a sudden collapse.
- Verticillium Wilt — Yellowing and dropping leaves working up from the bottom of the tree; most visible on young peach trees.
Fire blight is often lumped in with these but isn't a fungus — it's bacterial, so fungicides don't touch it.
A Season-by-Season Prevention Program
- Late winter, before buds break — coat the bark across the entire tree with a dormant oil treatment once air temps climb above 40°F.
- The week before bloom — apply Actinovate, then keep up a bi-weekly treatment through harvest if the tree had disease the year before. For peach leaf curl or brown rot specifically, a copper fungicide (Bordeaux mixture or Liqui-Cop) is the standard alternative.
- Early spring — a trunk-area drench of Actinovate and Thrive protects the roots; a foliar spray of Azamax, Spinosad, kelp extract, and Actinovate covers new leaf growth on both sides.
- All year — clear fallen leaves and fruit; that's where scab and brown rot overwinter.
Skip the spray program entirely if the tree had no disease last season — healthy soil, a 3–4 inch mulch ring, and reduced stress are usually enough.
Frequently Asked Questions
How do I get rid of fungus on my fruit trees?
You can't cure fungal disease once it's infected a leaf or fruit, but you can stop it spreading and prevent it next year. Remove infected leaves and fruit, apply dormant oil in late winter, then follow with Actinovate or a copper fungicide at bloom.
Can a tree recover from fungal disease?
Yes, even though already-damaged tissue can't be reversed. Prune out infected wood, clean up debris, reduce stress with proper watering and mulch, and start prevention the following year.
What is the best fungicide for fruit trees?
Actinovate, used as both a soil drench and foliar spray around bloom, plus dormant oil in late winter. For stone fruit, a copper fungicide (Bordeaux mixture/Liqui-Cop) also handles leaf curl and brown rot.
What does fungal disease look like on a fruit tree?
Olive-green or black spots (scab), white powder on new growth (powdery mildew), fast-spreading brown spots on fruit (brown rot), reddish puckered leaves in spring (peach leaf curl), or orange pustules under leaves (rust).
Can you eat fruit from a tree with fungus?
Usually, once you cut away the affected part — scab mostly disfigures skin. Brown rot is the exception: discard the whole fruit rather than trimming, since it spreads through the flesh fast.
When should I spray my fruit trees with fungicide?
Late winter (dormant oil), the week before bloom (Actinovate or copper fungicide), then bi-weekly through harvest only if there was disease the previous year.
Prevention Beats Cure for Fungal Disease on Fruit Trees
There's no product that reverses damage a fungus has already done to a fruit tree's leaves or fruit. The trees that stay healthy and productive year after year are the ones kept on a consistent dormant-season and early-spring prevention program, not the ones treated only after spots show up.
