two-spotted spider mite

Symptoms

Yellow stippling on upper leaf surface, fine webbing.

Easily confused with

• cotton aphid

  How to tell them apart: Aphis gossypii (cotton/melon aphid): look for visible soft-bodied, pear-shaped insects 1-2 mm long, clustered densely on shoot tips, flower buds and the youngest leaf undersides; colour ranges from yellow-green to dark mottled green or near-black. They leave sticky shiny honeydew that turns into black sooty mould, and you can often see cast white skins and a pair of small tube-like cornicles at the rear of the body. Tetranychus urticae (two-spotted spider mite): you will NOT see obvious insects — look instead for extremely fine, dust-like specks (0.5 mm) that need a hand lens, each pale green-yellow with two dark spots, scattered on the leaf underside. Its signature is the dense pale stippling/bronzing of the upper leaf surface and very fine silken webbing strung between leaf edges and shoot tips, worst in hot dry conditions; there is no honeydew and no sooty mould.

• tomato spotted wilt virus

  How to tell them apart: Tetranychus urticae (two-spotted spider mite): look on the leaf UNDERSIDE for very fine, even pale-yellow to whitish stippling (countless tiny dots) that follows no defined pattern, plus delicate silk webbing in leaf axils and tip dieback; hold a leaf to the light and you see translucent flecks, and tiny moving mites and shed skins under a 10x lens. Damage spreads gradually from older lower leaves upward and worsens in hot, dry, dusty conditions. Tomato spotted wilt virus (TSWV) instead produces organised patterns: concentric chlorotic and bronze-to-purple RING SPOTS, line patterns and oak-leaf figures, often with one-sided (asymmetric) leaf distortion and brown-to-black necrotic streaks running along stems and petioles. TSWV shows NO webbing and NO mites; growing tips may collapse and wilt one-sidedly, and symptoms appear on young as well as old leaves at the same time.

• iron-deficiency chlorosis

  How to tell them apart: Two-spotted spider mite (Tetranychus urticae): look on the UNDERSIDE of leaves for very fine pale stippling — a sandblasted, finely dotted pattern of tiny chlorotic specks evenly scattered across the whole blade, including over the veins. Affected leaves turn dull, bronzed and dusty-grey, and you will find fine silken webbing in leaf axils and tip clusters plus moving pinhead-sized mites (often with two dark body spots). Damage is worst in hot, dry, dusty conditions and on older, sun-exposed leaves. Iron-deficiency chlorosis (abiotic_chlorosis_iron) is completely different: it shows uniform interveinal yellowing on the YOUNGEST leaves while the veins stay sharply green (a green net on a yellow leaf), with no stippling, no bronzing, no webbing and no mites; it is symmetrical, linked to alkaline/waterlogged soil, and the leaf surface stays smooth.

• citrus greening (Huanglongbing, HLB)

  How to tell them apart: Candidatus Liberibacter asiaticus (Huanglongbing / citrus greening) shows ASYMMETRIC blotchy mottle — patchy yellow-green islands that do NOT mirror across the leaf midrib, often with corky, swollen, raised veins and overall yellow shoots; fruit stay small, lopsided and green at the stylar (bottom) end with aborted, dark, abortive seeds and a bitter taste. Tetranychus urticae (two-spotted spider mite) instead causes fine, evenly distributed pale stippling and silvery-bronze speckling, mainly on the UPPER leaf surface, with fine silk webbing and tiny moving mites plus shed white skins on the LEAF UNDERSIDE; damage is symmetric and worst in hot, dry, dusty conditions. Look for webbing and live mites under a hand lens (mites) versus midrib-crossing asymmetric mottle and corky veins (HLB). Huanglongbing is an EU quarantine organism — if you see asymmetric mottle with corky veins and lopsided green-bottomed fruit, do NOT treat it as a mite problem; report it to your national plant protection organisation (NPPO).

• powdery mildew (ornamentals)
• Cucumber mosaic virus (CMV)

  How to tell them apart: Tetranychus urticae (two-spotted spider mite) produces very fine, pale pinprick stippling that is densest along the midrib and leaf base of dahlia foliage; the whole leaf turns dull bronze-grey as damage builds, and fine silken webbing with tiny moving specks (the mites, often with two dark body spots) appears on the leaf undersides. Damage spreads fastest in hot, dry, dusty weather and from the lower, older leaves upward. Cucumber mosaic virus instead gives a true mosaic: irregular light-and-dark green blotches or yellow mottling with no stippling pattern, often with vein-clearing, leaf puckering, narrowing or distortion of new growth, and sometimes ring patterns. CMV symptoms are systemic (spread evenly through the plant, no mites or webbing) and do not wipe off or change with watering.

• edema (water blister)

  How to tell them apart: Edema (oedema) is an abiotic disorder: on Ficus lyrata you see raised, water-soaked blisters or corky brown bumps on the leaf undersides and along veins, evenly distributed, with NO webbing and NO living organisms. It appears after over-watering, cool nights or low light when roots take up more water than the leaves release. Tetranychus urticae (two-spotted spider mite) instead causes fine pale-yellow stippling on the UPPER leaf surface, fading to bronzing, plus tiny moving dots and delicate fine webbing on leaf undersides and between stem and petiole. The decisive tells: webbing + stippling + crawling mites = spider mite; raised corky water-blisters with no webbing and no movement = edema.

• silverleaf whitefly

  How to tell them apart: Bemisia tabaci (tobacco/silverleaf whitefly): look on the leaf underside for tiny (1.5 mm) moth-like flies that hold their wings tent-like over a yellowish body and rise in a small white cloud when the plant is shaken; along the veins you find oval, flat, scale-like translucent nymphs plus sticky honeydew and black sooty mould on lower leaves. Tetranychus urticae (two-spotted spider mite): there are no flying insects at all — only barely-visible 0.5 mm specks (pale green to orange with two dark spots) on the underside, fine pale stippling that becomes a bronze/silvery sandblasted look, and the diagnostic giveaway is fine silk webbing across leaf tips and between stems, worst in hot, dry conditions. Honeydew/sooty mould points to whitefly; webbing and a gritty bronze sheen point to mites.

• Japanese beetle

  How to tell them apart: Popillia japonica (Japanese beetle): look for shiny metallic-green adult beetles ~10 mm long with coppery wing covers and tufts of white hair along the body sides, feeding openly on the upper leaf surface in daylight. The damage is true skeletonisation — the soft tissue between the veins is chewed away, leaving a coarse, lace-like network of intact veins and irregular ragged holes; there is no webbing. Damage starts on sun-exposed upper foliage and you can often see the beetles or their droppings on the leaves. EU-QUARANTINE: Popillia japonica is a notifiable quarantine pest in the EU — if you see these beetles, photograph them and report immediately to your National Plant Protection Organisation (NPPO) before treating. Tetranychus urticae (two-spotted spider mite): damage is a fine, pale stippling of tiny dots on the leaf, especially on the underside, that merges into a dull bronze, grey or scorched look; the leaf tissue stays in place (no holes), and you will see fine silken webbing on the undersides and leaf tips in warm dry conditions. The mites themselves are minute (~0.5 mm) yellow-green specks with two dark spots, visible only with a hand lens. Mite outbreaks worsen in hot, dry, dusty weather, whereas beetle damage shows the insect itself.

• pepper mild mottle virus
• longtailed mealybug
• anthracnose

  How to tell them apart: Colletotrichum gloeosporioides (tea anthracnose) produces defined lesions that begin as small water-soaked or pale flecks and enlarge into brown-to-grey necrotic blotches, often with a darker margin and faint concentric zonation, typically starting at leaf tips or margins on mature leaves; in humid weather tiny black fruiting dots (acervuli) appear on the dead tissue and there is no webbing or movement. Tetranychus urticae (two-spotted spider mite) causes fine pale stippling and a dull bronze or silvery sheen spread diffusely across the upper leaf surface, never sharp brown blotches; turn the leaf over and you find live moving mites, cast skins and fine silk webbing along the midrib and undersides, especially in hot dry conditions. The key test: anthracnose damage is fixed, spotted and may bear black dots, while mite damage moves, has webbing and tiny mites underneath.

• brown soft scale

  How to tell them apart: Coccus hesperidum (brown soft scale) shows up as flat, oval, yellowish-brown waxy bumps about 3-4 mm long, clustered tightly along leaf midribs, stems and the undersides of leaves on Camellia sinensis; they do not move and feel firm if you press them. They secrete sticky honeydew that coats the foliage and turns black with sooty mould, and the leaf yellowing is general or in patches around the feeding sites. Tetranychus urticae (two-spotted spider mite) instead leaves no bumps at all: look for very fine pale stippling or speckling on the upper leaf surface that merges into a dull bronzed or silvered look, plus fine silk webbing on leaf undersides and at shoot tips. The mites are tiny moving dots (under 0.5 mm), often with two dark spots, most damaging in hot dry weather.

• carnation rust

  How to tell them apart: Tetranychus urticae (two-spotted spider mite) feeds on the LOWER leaf surface, producing very fine, evenly scattered pale-yellow to silvery stippling that coalesces into a dull bronze-grey mottle; in heavy infestations look for tiny moving mites and fine silk webbing along leaf margins, shoot tips and at the junction of leaf and stem. Damage is worst in hot, dry conditions and there are no raised spots — the surface stays smooth. Uromyces dianthi (carnation rust) starts as pale, slightly raised chlorotic flecks but quickly erupts into distinctly RAISED, powdery pustules that rupture to release cinnamon- to chocolate-brown spores, mostly on the lower leaf surface and along stems, often arranged in rings or elongated streaks. Rub the leaf: rust leaves a rust-brown powder on your finger and the spots are bumpy, whereas mite stippling is flat, dry and leaves no coloured powder.

• Fusarium leaf spot of Dracaena

  How to tell them apart: Tetranychus urticae (two-spotted spider mite) produces fine, even pinprick stippling that starts on the leaf undersides of Dracaena fragrans and spreads as a sandy, silvery-bronze speckled wash; look for tiny moving dots, two dark body spots, and—diagnostically—fine silk webbing in leaf axils and along margins when populations build. Fusarium proliferatum (Fusarium leaf spot) instead makes discrete tan-to-reddish-brown spots, often water-soaked at the edge with a yellow halo, concentrated on young and emerging central leaves; spots stay fixed in place, enlarge into irregular blotches, and never produce webbing. The single clearest field test: turn the leaf over and look for webbing and moving mites (mite) versus fixed, halo-ringed necrotic spots on new growth (Fusarium).

• citrus mealybug

  How to tell them apart: Planococcus citri (citrus mealybug) shows up as soft, oval, 2-4 mm insects coated in white mealy wax, clustered in leaf axils, along the petioles and where stems meet the Monstera's aerial roots; they leave white cottony tufts and sticky honeydew that often turns into black sooty mould. Tetranychus urticae (two-spotted spider mite) is barely visible (under 0.5 mm), pale green to amber with two dark dorsal spots, living on the undersides of leaves and producing fine silken webbing rather than waxy lumps, with damage seen as a fine pale stippling or speckling across the leaf surface. So: discrete cottony bodies you can pick off in axils plus sticky residue = mealybug; almost-invisible moving dots, dust-fine webbing and a stippled bronzing leaf = spider mite, worsening in hot dry air.

• strawberry red core

  How to tell them apart: Phytophthora fragariae (red core / red stele root rot) is a soilborne disease: above ground you see whole plants stunting, wilting and turning dull bluish-green to red, typically in cold, wet, poorly drained patches of the bed. The decisive sign is below ground — dig a plant and split a root lengthwise: rotted lateral roots give a 'rat-tail' look and the central core (stele) shows a distinctive red to red-brown discolouration. There is no webbing and no insects. It is a common, established soilborne disease that you manage normally with good drainage, resistant varieties and crop rotation — no official reporting is required. Tetranychus urticae (two-spotted spider mite) is a leaf-surface pest favoured by hot, dry, dusty weather: upper leaf surfaces show fine pale stippling and bronzing, and the tell-tale signs are fine silk webbing plus tiny moving mites and round eggs on the leaf underside, visible with a hand lens. Roots stay healthy and white with no red stele.

• Pythium damping-off + root rot (multi-host)

  How to tell them apart: Pythium ultimum is a soil-borne root rot, while Tetranychus urticae (two-spotted spider mite) is a sap-sucking leaf pest — the decisive check is roots versus leaf undersides. With Pythium, gently unpot the plant: roots are brown, soft, mushy and the outer skin slips off easily leaving bare strings, the stem base may darken, and yellowing-wilting strikes the whole plant from the bottom up despite moist medium. With Tetranychus you find no root damage; instead the upper leaf surface shows fine pale-yellow to silvery stippling (tiny dots), the underside carries minute moving mites and, in heavier attacks, fine silk webbing across leaf tips and between stems, with symptoms worst on the hottest, driest, most light-exposed leaves.

• clematis wilt (leaf & stem spot)

  How to tell them apart: Calophoma clematidina (clematis wilt fungus) kills by infection: look for discrete dark brown-to-black lesions and cankers on the stem, typically at a leaf node low on the vine, from which an entire shoot loses turgor and collapses suddenly — the wilted leaves and shoot tips blacken and flop within a day or two even while soil is moist, and the crown below the lesion often stays alive and re-sprouts. Tetranychus urticae (two-spotted spider mite) damages by feeding: the leaves show a fine pale stippling that merges into a dull bronze or scorched-tan cast spread evenly over the upper surface, with fine silken webbing across the leaf undersides and tips and tiny moving mites visible with a hand lens; damage builds gradually in hot dry weather rather than as an overnight collapse, and there is no discrete black stem lesion. In short: a single black stem canker plus sudden turgor loss points to the fungus, whereas even bronzing with webbing and visible mites and no stem lesion points to the mite.

• overwatering / waterlogging

  How to tell them apart: Overwatering yellows oregano uniformly and evenly: whole leaves fade to pale green-yellow from the lower/inner canopy outward, stems may feel soft and the soil stays wet, with leaves dropping while still limp and the undersides clean. Tetranychus urticae (two-spotted spider mite) instead produces fine pale pinprick stippling that gives a sandblasted, mottled look, often on the upper leaf surface, while the underside carries tiny moving specks (the mites, often with two dark body spots), pale eggs and — once advanced — fine silk webbing in the leaf axils and tips. Turn a leaf over and use a loupe: webbing plus crawling mites confirms spider mite; a clean wet root zone with even, soft yellowing and no stippling points to overwatering.