What's Eating My Zucchini?
Zucchini's most devastating pest never touches a leaf — it works inside the stem, and by the time the plant wilts, the damage is done. Check the base of the plant first.
The usual suspects
Squash vine borer
The signs: A vigorous plant that suddenly wilts despite moist soil. At the base of the stem: a hole oozing wet, sawdust-like frass.
What it looks like: The culprit inside is a fat white caterpillar; the adult is a daytime-flying orange-and-black moth that resembles a wasp, laying eggs at the stem base in early summer.
What to do: Wrap stem bases in foil at planting, or cover plants until bloom. If a vine wilts, slit the stem lengthwise, remove the borer, and bury the wounded section — squash often re-roots at the nodes.
Squash bugs
The signs: Speckled yellowing leaves collapsing into brown crisps; bronze egg clusters ranked on leaf undersides.
What it looks like: Gray-brown shield-shaped bugs congregating at the crown and under leaves.
What to do: Crush eggs weekly, trap adults under a board overnight and collect at dawn, clean up debris in fall so they have nowhere to overwinter.
Cucumber beetles
The signs: Pitted leaves and scarred young fruit early in the season.
What it looks like: Small yellow beetles with black stripes or spots.
What to do: Row cover until flowering; sticky traps for stragglers.
Aphids
The signs: Curled sticky leaves and, later, mottled leaves from the viruses they carry.
What it looks like: Soft green or dark clusters under leaves.
What to do: Water blast, insecticidal soap, and reflective mulch to confuse arrivals.
When it's not a pest at all
Baby zucchini that yellow and rot from the blossom end were never pollinated — plant flowers, not a pest problem. White dusty coating on older leaves is powdery mildew, and the pale gray-green mottling along leaf veins on many varieties is just natural variegation.
Or just point your phone at it
Snap a photo of the leaf, the bug, or the droppings, and Harold — the advisor built into Homestead Paradise — names what he sees, tells you friend or foe, and what he'd do next. Honest when he's unsure, and careful where it counts.
Put Harold's Eyes on it — free 14-day trial