Tarsonemid mites (family Tarsonemidae, the thread-footed mites) are tiny, about 0.1-0.3 mm, with four pairs of legs; the hind legs of females are thread-like. The broad mite Polyphagotarsonemus latus and cyclamen mite Phytonemus pallidus are the main plant pests. UF/IFAS describes broad mite feeding on young growth and the twisted, bronzed tissue that follows.
In practice
Tarsonemid damage looks like a nutrient or herbicide problem: glossy, twisted, stunted new growth. Confirm at 40-60x on the youngest leaves. Males carry quiescent females to new leaves, and broad mites can ride on whiteflies and aphids, so control of those insects also limits spread.
Don't confuse with
- Eriophyid mites: two pairs of legs, carrot-shaped.
- Spider mites: larger, webbing, visible at 10x.
Polyphagotarsonemus latus, a microscopic tarsonemid mite whose toxic feeding twists, glazes and stunts new growth; often mistaken for calcium deficiency or heat stress.Phytonemus pallidus, a tarsonemid mite related to the broad mite that distorts new growth on many ornamentals; rarely reported on cannabis and often confused with broad mite.Bag appeal is how good flower looks in the bag or jar, frost, colour, density and trim, which sells cannabis but does not measure its quality.Small white-winged sap-sucking insects of the family Aleyrodidae, mainly Trialeurodes vaporariorum and Bemisia tabaci, that fly up when disturbed and coat leaves in honeydew.Small soft-bodied sap-sucking insects of the family Aphididae that cluster on stems and leaf undersides, excrete sticky honeydew and multiply rapidly by live birth.A family of microscopic, carrot-shaped mites with only two pairs of legs; includes the hemp russet mite, invisible without about 40-60x magnification.Tetranychus urticae, the commonest cannabis mite indoors: a 0.5 mm sap-feeder that stipples leaves pale and spins webbing, breeding fastest in hot, dry rooms.
