Broad mite
A thread-footed mite about 0.2 mm long, a quarter the size of a spider mite and invisible without a microscope or a strong lens. It feeds on the newest leaves, buds and small fruit and injects a toxic saliva. Shoot tips become twisted, hardened and bronzed, leaves turn down, and flowers abort. It is mainly a pest of greenhouse pepper, bedding plants and houseplants such as African violet, begonia, impatiens and ivy. The damage shows only as the tissue grows, so it often appears weeks after the mites arrived and continues after they are controlled. Predatory mites released early are the main biological tool. Oil, soap and sulfur sprays help, if they reach the mites.
Broad mite damage on a pepper shoot tip, with an inset of Polyphagotarsonemus latus under magnification. Photo: pending.
Identification
Adult females are about 0.2–0.25 mm (1/100 in) long, oval and swollen, translucent to light yellow, amber or green, with a faint pale stripe down the back. Males are about half the size and have no stripe. Sources differ on magnification: UF/IFAS says a 10× or stronger hand lens, UC IPM a microscope or at least a 20× lens, and OMAFRA finds spotting them with a hand lens near impossible.
The eggs are the easiest thing to recognise. They are clear ovals about 0.08 mm long with 29–37 white tufts on the upper surface, which look like rows of tiny pegs. OMAFRA's rule is that one egg plus the characteristic damage is usually enough to confirm broad mite. Males can also be seen carrying the pale, pointed resting female nymphs to new leaves.
The related cyclamen mite causes similar distortion. Its body has nearly parallel sides and its eggs are smooth, and it prefers cool conditions. Broad mite tapers towards the rear, has studded eggs and prefers warmth (UC IPM).
Easily confused with
- Cyclamen miteAlso a pestUnder a microscope, broad mite's body tapers, widest between the second pair of legs, and its eggs carry rows of pale pegs. Cyclamen mite has near-parallel sides and smooth eggs.
- Herbicide injuryHarmlessHerbicide drift also twists and bronzes new growth. Only mites or their pegged eggs on the growing points, seen under a microscope, confirm broad mite.
- Boron deficiency or cool-weather leaf curlHarmlessBoron (or zinc) deficiency and, on New Guinea impatiens, cool humid weather also curl new leaves. One broad mite egg on damaged tips is usually enough to confirm the mite.
Damage symptoms
The damage comes from the saliva rather than from sap loss, so a few mites can do a lot. The distortion shows only when the fed-on tissue expands. OMAFRA finds this often happens 20–30 days after the crop was infested, and new damage can keep appearing after the mites are dead. Other causes produce the same twisting: 2,4-D, glyphosate and other herbicides, boron or zinc deficiency, and, on New Guinea impatiens under cool, humid conditions, a physiological disorder. Confirm with a microscope before treating.
- Shoot tips twisted, hardened and stunted, with short internodes and a tufted look
- Young leaves cupped, curled downward, thickened and brittle
- A copper, bronze or purplish colour on growing points and the lower leaf surfaces
- Buds deformed, discoloured or dropped; flowers that never open properly
- Side buds breaking in a cluster on pepper, and fruit discoloured where the mites fed
Lifecycle & degree days
Development is fast in warmth. On azalea leaves, Luypaert et al. (2014) measured egg to adult in 4.2 days at 77 °F (25 °C) and 13.3 days at 59 °F (15 °C), with an optimum near 86 °F (30 °C); UC IPM gives 6–10 days in warm conditions. Broad mite does best when it is warm and humid. It spreads by walking, by males carrying female nymphs, on workers and on hanging baskets. It can also ride on whiteflies from plant to plant. It attacks greenhouse plants in temperate and subtropical regions, and has a wide outdoor host range in the tropics (UF/IFAS).
- Egg to adult
- 4 days at 77 °F (25 °C); 13 days at 59 °F (15 °C)
- Development range
- 50–97 °F (10–36 °C); optimum about 86 °F (30 °C)
- Eggs per female
- 30–76 (UF/IFAS); about 20 (UC IPM)
- Damage appears
- Often 20–30 days after infestation
- Favoured by
- Warm, humid conditions
Host crops
A wide host range, worldwide. UF/IFAS lists pepper and chilli, tomato, eggplant, beans, potato, cotton, citrus, mango and papaya among its crops, and it was recorded on US watermelon for the first time in 2006. Ornamental hosts include African violet, azalea, begonia, chrysanthemum, cyclamen, dahlia, gerbera, gloxinia, impatiens, ivy, lantana, peperomia, snapdragon, verbena and zinnia. In California it is mainly a greenhouse and nursery pest, plus coastal lemons from late July to early October (UC IPM).
Monitoring & action thresholds
No numeric threshold is published. Damage occurs at very low densities and lags the infestation (OMAFRA), so the practical trigger is confirmation: characteristic tip damage plus a mite or egg seen under the microscope. On crops that have had broad mite before, OMAFRA suggests a stricter routine of washing random growing tips in alcohol and checking the washings under a microscope.
Walk susceptible crops regularly and look at growing points, buds and the youngest leaves, not the older foliage. Suspect broad mite when new growth distorts and nothing is visible on it. Confirm under a microscope, or send samples to a diagnostic lab (UMass). Check small fruit too: UF/IFAS notes the mites are usually seen on the newest leaves and small fruit, and on fruit trees the damage is usually on the shaded side of the fruit. Scout infested areas last, because the mites travel on people.
Biological control
Predatory mites are the biological option, and early release is the key point. OMAFRA names the Swirski mite, Neoseiulus californicus and N. cucumeris as able to suppress broad mite. They should go in early in susceptible crops and at high rates for the life of the crop. The Swirski mite controlled broad mites on sweet pepper plants in greenhouse trials (van Maanen et al. 2010), but a Belgian trial on ivy found it needed at least 64 °F (18 °C) to work. UConn lists Amblyseius andersoni as a broad-mite predator, but no trial result for it against broad mite was found. Where the crop tolerates it, some consultants find biocontrol works better if they first knock the mites back with a mineral-oil spray. UC IPM adds that Argentine ants, dust, miticides and broad-spectrum persistent insecticides all disrupt these predators.
Cultural controls
Clean stock and hygiene come first, because broad mite travels on plants and people.
- Start with mite-free plants, and keep new plants of susceptible species away from infested ones
- Scout and work in infested areas last, and clean the greenhouse thoroughly after an outbreak
- Do not hang infested baskets above other plants
- Throw out houseplants whose new growth stays distorted rather than nursing them along
- Dip small plants in hot water at 109–120 °F (43–49 °C) for 15 minutes, which UF/IFAS reports kills the mites without injuring the plant
- Control ants and keep dust down, since both protect broad mites from their predators
Chemical, last resort
- Insecticidal soapREI 12 h
- Narrow-range oilREI 4 h
- Wettable sulfurREI 24 h
- Abamectin (professional use only)REI 12 h
Sources
UF/IFAS EDIS EENY-183 (IN340), Broad Mite, Polyphagotarsonemus latus (Fasulo and Rhodes)
UC IPM, Broad Mite and Cyclamen Mite (Home and Landscape)
UMass Extension, Broad Mite and Cyclamen Mite (greenhouse fact sheet)
Jandricic, Battling broad mite in spring crops, ONfloriculture (OMAFRA), 2022
Luypaert et al., Temperature-dependent development of the broad mite, Exp. Appl. Acarol. 2014
van Maanen et al., Biological control of broad mites with Amblyseius swirskii, Exp. Appl. Acarol. 2010
Cornell IPM, Amblyseius swirskii biocontrol fact sheet, 2022
UConn Extension, Biological Control of Two-Spotted Spider Mites (Pundt, updated 2019)
Audenaert et al., Acaricides and predatory mites against the begonia mite on Hedera helix, 2009
UC IPM, Relative Toxicities of Pesticides Used in Floriculture and Nurseries (updated 2022)
UC IPM Pest Management Guidelines: Cucurbits — Whiteflies, and Tomato — Tomato Russet Mite (REIs)
Page status
Drafted from the sources below, then checked claim by claim against those sources on 23 September 2026.
Suggest a correction →Broad mite by crop
The same pest behaves differently on different hosts. Each page below gives the host-specific control, rate and threshold.