Cotesia congregata and other Braconidae
Braconid wasps- Kind
- Wild — attract it
- Best for
- Wild larval parasitoids; avoid broad sprays
Pest
Tomato pinworm
Keiferia lycopersicella
The short answer
A small grey moth whose caterpillar mines and folds tomato leaves, then bores into the fruit under the calyx. The entry hole is pin-sized, hence the name, and brown frass collects at the edge of the cap. It belongs to warm regions: southern California, Texas, Mexico and south and central Florida, plus greenhouses further north. It does not overwinter outdoors in colder areas. Where it is established it can infest most of the fruit. Most of the control is sanitation: clean transplants, destroying old tomato plants and a break between crops.
hero macro · larva in a folded tomato leaf beside a blotch mine
Late-instar Keiferia lycopersicella in a folded tomato leaflet, next to an earlier blotch mine. Photo: pending.
Identification
The larva is small, about 3/8 inch (1 cm) long when mature. Young larvae are light-coloured and smooth, without obvious bristles, even under a hand lens. Later instars, usually found in the fruit, are grey or yellowish with an irregular red or purple band across each segment; UF/IFAS describes them as purplish-grey. The adult is a small light grey moth about 1/4 inch (6–8 mm) long, flecked with black, with a wingspan of about 1/2 inch.
Two things are easily confused with it. Leafminer flies (Liriomyza) make narrow, winding tunnels, while pinworm makes a blotch-shaped mine and then folds the leaf. Fruit damage can look like tomato fruitworm, but the fruitworm chews large, deep holes, while the pinworm leaves a small dry burrow under the calyx that does not go far into the fruit. The South American tomato pinworm, Tuta absoluta, is a different species, and much of the recent research under the name 'tomato pinworm' is about it.
Easily confused with
- Leafminer fliesAlso a pestMake narrow, winding (serpentine) mines with a string of black frass. Tomato pinworm makes blotch-shaped mines and then folds or ties the leaves.
- Tomato fruitwormAlso a pestChews large, deep holes into the fruit, especially at the stem end. Pinworm leaves a small, dry burrow under the calyx, with silk and frass.
Damage symptoms
Early damage is slight: a small blotch mine in the leaf. Later larvae fold and tie leaves, and heavy feeding can defoliate plants. The worst damage is to the fruit, which is entered under the calyx and contaminated with frass and silk, and can rot. UC IPM says that where it is abundant it can infest nearly 100% of the fruit.
- Blotch-shaped mines in the leaves, not narrow winding tunnels
- Leaflets folded or tied together with silk, a larva inside
- Pin-sized holes in the fruit under the calyx
- Brown, granular frass at the edge of the fruit cap
- Entered fruit contaminated with frass and silk, and sometimes rotting
Lifecycle & degree days
The whole cycle takes 21 to 67 days depending on temperature, and generations overlap, so numbers can build quickly through a long season. There are seven or eight generations a year in south Florida and in southern California. It does not overwinter outdoors in cold regions, and infestations there come from greenhouses or are carried in on seedlings, fruit or picking crates. In Florida it is a spring pest in the south and centre, and a summer to late-autumn pest in the north.
- Egg to adult
- 21–67 days, depending on temperature (UF/IFAS)
- Egg hatch
- 8.9 days on average, 4 at minimum (Elmore & Howland 1943, via UF/IFAS)
- Pupa
- 1–4 weeks (UF/IFAS ENY-461); 15 days minimum, 30 on average, in Elmore & Howland 1943
- Generations / yr
- 7–8, overlapping (south Florida, southern California)
- Overwinters
- Not outdoors in cold regions; carried on seedlings, fruit and crates, and in greenhouses
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Host crops
It feeds only on the nightshade family. Tomato is the crop it is named for; eggplant and potato are also hosts, and in Florida so are nightshade weeds such as horsenettle. UF/IFAS notes that pepper is not a host.
Monitoring & action thresholds
Action threshold
0.7 larva per plant (Florida, commercial)
UF/IFAS counts larvae on 20 plants up to the seventh true leaf and treats at an average of 0.7 per plant, then counts on one lower-canopy leaf per plant and treats at 0.7 per leaf. UC IPM treats at an average of 1–2 larvae per 6-foot row section. Both are commercial field figures. We found no garden threshold.
Look at the lower leaves for blotch mines and folded leaflets, and at the fruit for pinholes and frass under the calyx. Commercial growers use pheromone traps from planting. UC IPM sets one trap per 10 acres and at least two per field, and UF/IFAS starts mating disruption at 5 or more moths per trap per night. In a garden, inspect transplants before planting and reject any with mines.
Beneficial
Biological control
Parasitoids do a lot of the work where sprays do not get in their way. In Florida commercial tomato fields, UF/IFAS records 40–60% parasitism, rising later in the crop, and egg parasitism as high as 60–90%. The parasitoids it lists include braconid wasps (Apanteles species) and the egg parasitoid Trichogramma pretiosum. UC IPM says parasites can be important in unsprayed or lightly sprayed fields. Mating disruption with pheromone dispensers is not a beneficial insect, but UF/IFAS prefers it to insecticides because it spares these parasites. We found no trial of purchased Trichogramma releases against this pest, so the value of Trichogramma here is as a wild enemy to protect.
Trichogramma spp.
Trichogramma wasps- Rate
- 50k–100k /acre weekly (1–2 /ft² in gardens)
- Temp
- 18–29 °C best; weaker at 15 °C
- Best for
- Wild egg parasitoid; releases untested
Cultural controls
Pinworm infestations usually start from infested transplants or from old plants left standing. Breaking that chain is the most effective control.
- Check transplants for mines and larvae, and do not plant infested ones
- Pull and destroy tomato, eggplant and potato plants as soon as harvest ends
- Leave a break with no host crop before replanting — UC IPM calls a host-free period essential
- Keep new plantings away from old tomato, eggplant or potato crops
- Pick off folded leaflets and entered fruit and destroy them
Chemical, last resort
Once larvae are inside folded leaves or fruit, sprays reach few of them, and broad-spectrum products kill the parasitoids that do. Esfenvalerate is also highly toxic to bees: do not spray it on, or let it drift onto, flowering crops or weeds where bees are foraging.Check any product before it goes on. Open the compatibility matrix →
- MethoxyfenozideREI 4 h
- ChlorantraniliproleREI 4 h
- EsfenvalerateREI 12 h
Rating: the effect on this pest's natural enemies if a spray hits them or they feed on treated plants. REI is the re-entry interval on farm and greenhouse labels; home labels usually give none, so follow the label.
Sources
UC IPM Pest Management Guidelines: Tomato — Tomato Pinworm (Natwick et al., text 12/13, table 09/16)
UC IPM, Relative Toxicities of Insecticides Used in Tomatoes to Natural Enemies (09/16)
UF/IFAS EDIS EENY-074, Tomato Pinworm, Keiferia lycopersicella (Poe, rev. 12/2023)
UF/IFAS EDIS ENY-461, Arthropod Management for Tomato, Pepper, and Eggplant (rev. 05/2024)
UF/IFAS EDIS ENY-685, Scouting, Thresholds and Conservation of Beneficials on Tomatoes (rev. 12/2015)
Page status
Drafted from the sources below, then checked claim by claim against those sources on 23 September 2026.
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