Broad mite

The youngest leaves at the growing tip curl downward, go stiff and brittle, and the underside turns a shiny bronze or copper colour, as if lightly scorched or oiled. The growing tip bunches up tight and stops growing — like a little witches' broom of stunted, deformed leaves.

peppers, chillies and tomatoes get a rough, corky, grey-brown skin (russeting), often silvery cracks on the shoulders — the fruit looks scarred and won't sell.

— about 0.2 mm, far smaller than a grain of sugar, clear to pale amber and shiny. Even with a strong hand lens you'll struggle; you are hunting the damage, not the animal. It hides on the underside of the very youngest leaves and deep in the growing tip, where it's shaded and humid.

Unlike red spider mite, broad mite makes no webbing and the leaves bronze rather than show pale speckles. Unlike leaf-curl virus (spread by whitefly), broad-mite curling is on the newest growth with that oily bronze underside and hard, brittle feel — virus curl is usually yellower, blotchy and puckered. It can also look like hormone weedkiller drift or boron shortage; the giveaway for broad mite is the shiny bronzed underside on the youngest leaves plus corky, russeted fruit.

from the fast-growing (development) stage through the fruiting (mid-season) stage — whenever the plant is pushing lush new tips. Warm, sticky weather (about 21–30°C with humid, still air) and shaded, sheltered or greenhouse corners are where it explodes, so check those spots first.

so you cover all four corners and the middle — not just the row nearest the path, where you always end up looking.

At about 10 stops, bend down and inspect the youngest 2–3 leaves and the growing tip of each plant. Turn the young leaves over and tilt them to the light: you're checking for a shiny bronze underside, downward-curled brittle edges, and bunched, distorted tips.

Because the mite is too small to see and the damage shows up before it becomes obvious, treat as soon as you find even a few plants with curled, bronzed young leaves or twisted growing tips — don't wait for a big count. If you see it on 1 plant, check the neighbours; a cluster of affected tips means it's spreading and you should treat now.

Watch whiteflies at the same time — they ferry broad mite between plants, so lots of whitefly means the mite will travel fast.

Plant only clean, healthy transplants (inspect the growing tips before you buy or move seedlings) — this is the single most important step, since most outbreaks arrive on infested seedlings. Keep your hands and tools clean when moving between plants, and control whiteflies, which carry the mite from plant to plant.

As soon as you spot badly curled, bronzed, witches-broomed plants, pull them out and destroy them (burn or bury away from the field) so they stop feeding the outbreak — don't just drop them between the rows.

Tiny predatory mites (such as Amblyseius / Neoseiulus types) hunt and eat broad mite and can hold it down on their own. Protect them by not blanket-spraying broad, harsh insecticides — those poisons kill the good mites faster than the pest and make the problem far worse.

Broad mite lives only on the newest growth, so any spray must soak the undersides of the young leaves and the growing tips — that's where the mites are. Spray thoroughly and repeat as the plant keeps pushing new growth, because fresh shoots are unprotected.

If it keeps spreading despite the steps above, use a targeted miticide of the abamectin class (or sulphur), directed straight at the young leaf undersides and growing tips. Abamectin is a contact/translaminar miticide — it kills mites it touches or that feed on the sprayed leaf, so thorough coverage is everything. Safety: cover your skin, eyes, nose and mouth, spray in the cool of the day with the wind at your back, keep it off food, water, children and bees, wash yourself and your clothes afterwards, and respect the pre-harvest interval (the minimum days you must wait between spraying and picking — read the label). To stop the mite building resistance (surviving the poison), rotate to a different chemical group each time rather than using abamectin over and over.

Re-treat the young growth every few days and keep roguing the worst plants. If new tips keep coming out curled and bronzed after repeated treatment, switch to a different chemical group and lean harder on clean material and whitefly control. When a plant is fully stunted with a dead, broomed growing tip and russeted fruit, it will not recover — pull it, destroy it, and protect the healthy plants around it instead of spending more spray on a lost one.