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Intonsa thrips: what Australian growers need to know

Intonsa thrips: what Australian growers need to know

Intonsa thrips (Frankliniella intonsa) is the newest thrips in Australian horticulture, and it has already cost south-east Queensland berry growers dearly. This page covers what it is, how it differs from the thrips you already know, where it has been found, why it gets away from growers so quickly, and how a contact spray fits into an IPM program built around beneficials.

You will hear a few names for it: intonsa, intonsa flower thrips, Eurasian or European flower thrips, and on the Sunshine Coast, “New Zealand thrips”, because New Zealand growers have dealt with it since it was first recorded there in 2002. (In North America “eastern flower thrips” usually means a different species, F. tritici, so the scientific name is the safest one to use when you talk to an agronomist or a lab.)

Product: Py-Bo Natural Pyrethrum + Piperonyl Butoxide Insecticidal Concentrate (APVMA 53738). Always read the current label. The label is the law.

Why intonsa is a big deal

  • It’s new. Biosecurity Queensland confirmed the first Australian detection in early April 2026, after a berry farm at Elimbah reported unusually high thrips numbers and damaged raspberries. Further detections followed in blackberry and strawberry crops at Ningi and Wamuran.
  • It spread fast. By September it was being reported through strawberry, raspberry and blackberry blocks across the Moreton Bay and Sunshine Coast regions. Queensland Strawberry Growers told ABC Rural that most farms in the south-east were losing at least half their crop.
  • It hit at peak pick. One Sunshine Coast grower told FreshPlaza he binned roughly 85% of the fruit picked over a two-week stretch in August.
  • Common sprays struggled. In Biological Services’ field trials, six insecticides commonly used on thrips gave only 5–20% control, and numbers bounced straight back.
  • It’s not just a berry pest. Overseas it attacks beans, zucchini, cucumber, melons, capsicum, asparagus, lucerne, cotton, cut flowers and ornamentals, and it carries tomato spotted wilt virus and impatiens necrotic spot virus.

Intonsa is listed as an emergency plant pest. At the time of writing, the national committee (CCEPP) was still assessing whether eradication is technically feasible. We have not seen confirmed detections outside south-east Queensland, but Biological Services has flagged the risk to interstate berry areas.

Intonsa or the thrips you already have?

You can’t reliably tell intonsa from western flower thrips by eye. A lens shows you have thrips; a microscope tells you which.

Intonsa thrips (F. intonsa)Western flower thrips (F. occidentalis)Plague thrips (Thrips imaginis)
Status in AustraliaNew, first confirmed April 2026 (SEQ)Established since 1993, all statesNative
Adult sizeAbout 1.2–1.8 mmFemales 1.4–1.8 mmFemales 1.1–1.3 mm
LookFemales large and dark; males smaller and paler brown. Colour varies with diet and conditionsYellow to brown, colour variesLight brown to yellow
LarvaeBright yellow to orangeSimilar size to intonsa larvae; hard to tell apart in the fieldHard to tell apart in the field
Lab clueShort hairs (postocular setae) behind each eyeLong hairs behind each eyeDifferent genus; separated under the microscope
Field cluePre-pupal larvae often sheltering under the strawberry calyxFlowers and young fruitSwarms into blossom from weeds and native plants in spring

If you see unusually heavy or out-of-season thrips pressure, get a professional ID. Collect 20–30 flowers per area into labelled zip-lock bags, or tap flowers over white paper and put the thrips in a vial of 70% alcohol. If you think you have a new or unusual pest, call the Exotic Plant Pest Hotline on 1800 084 881.

What the damage looks like

Intonsa feeds and lays eggs in flowers and young fruit. Damage looks a lot like western flower thrips damage, only heavier:

  • Strawberries: bronzing and scarring on green fruit, often starting under the calyx. Damaged stigmas, styles and petals. Bronzed fruit goes hard and dull, and the scarred skin splits easily in rain.
  • Raspberries: silvering on ripening fruit.
  • Blackberries: at high numbers, flower abortion and uneven drupelet development.
  • Other crops and nursery stock: browning, scarring, distortion, poor fruit set and bud drop.

Why it gets away from you: the life cycle

Intonsa’s biology explains why growers in 2026 said “you can’t catch up”.

  • Fast generations. In good conditions it goes from egg to adult in about 8–13 days.
  • Lots of eggs. A female can lay up to 200 eggs over a life of roughly 18–35 days.
  • No male needed. Females can reproduce without mating, so a few arrivals can seed a block.
  • Active in the cool. It does best at about 20–25 °C but stays active from about 10 °C to 36 °C. That means it can build up in a crop earlier in the season than western flower thrips.
  • Protected stages. Eggs sit inside plant tissue, and the non-feeding stages hide under the calyx or drop to the soil. A contact spray, and many predators, don’t reach these stages.

The stage you can actually win against is the larva. Larvae feed openly on flowers and young fruit, and they are what predatory mites eat. Every larva that reaches adulthood can start the next round of egg laying. Our Break the life cycle page explains how timing a second spray catches the stages the first one missed.

Get ahead early: monitoring

  • Start before flowering builds. Intonsa’s tolerance of cool weather means it may be in the crop before you would normally look for thrips.
  • Blue or yellow sticky traps pick up flying adults. Traps tell you thrips are arriving, not which species, so back them up with flower checks.
  • Tap flowers over a white surface or check a set number of flowers per row each week. Lift the calyx on young fruit and look for yellow-orange larvae.
  • Record what you find so you can see numbers rising before the fruit shows bronzing.
  • Get an ID the first time you see heavy pressure, and whenever thrips turn up somewhere unusual.

IPM: beneficials first, and early

The growers and consultants dealing with intonsa all say the same thing: beneficials work, but only if they’re in place before numbers climb. In 2026 many releases started too late, when populations were already too high for predators to pull back.

  • Predatory mites (Neoseiulus cucumeris) eat young thrips larvae. In Biological Services’ trials, regular high-rate releases reduced larvae by 20–40% for up to four weeks. They needed repeat releases and good coverage across the whole crop, because the mites don’t spread far by themselves.
  • Pirate bugs (Orius) eat larvae and adults. Trial blocks with established Orius had the least damage, and the consultants expect early Orius establishment, backed by cucumeris, to be the key in future Queensland strawberry seasons.
  • Protect the predators. Broad-spectrum or long-residual sprays can knock out beneficials for weeks or months and leave intonsa with the crop to itself. Talk to your IPM consultant or beneficials supplier before you spray anything near a release.
  • Rotate modes of action and follow label directions for any chemical you use. Greenlife Industry Queensland lists resistance management as critical for intonsa.

Where Py-Bo fits

Thrips are named on the Py-Bo label for fruit and vegetable crops, cut flowers and ornamental plants, at 1 mL per litre of water (100 mL per 100 L), with a 1-day withholding period on edible crops. Py-Bo has not been trialled specifically against intonsa, so treat it as a contact knockdown tool within your IPM program, not as a cure.

Where it can help:

  • Knocking down a flare-up of larvae and adults on flowers and young fruit, when monitoring shows numbers climbing faster than the beneficials can handle.
  • Close to harvest, because the 1-day withholding period suits multi-pick crops like strawberries.
  • Spot-spraying hotspots rather than blanket spraying the whole block, which leaves more of your predators untouched.

Things to get right:

  • It has to hit the insect. Py-Bo is a contact spray. Aim into open flowers, under the calyx, onto young fruit and the undersides of new leaves. Water-sensitive paper in the flowers shows you whether the spray is getting there. See spray coverage for set-up tips.
  • Follow up. Eggs in the tissue and stages in the soil survive the first spray. Check again within a few days and re-spray if new larvae or adults appear. Timing is on the aphids and thrips spray timing page.
  • Beneficials. Like any insecticide, Py-Bo can kill beneficial insects it hits. Agree timing with your beneficials supplier, and spot-spray where you can.
  • Bees. Do not spray plants in flower while bees are foraging. Late evening, after bees have finished, is the usual choice in flowering berries.
  • Organic blocks. Py-Bo contains piperonyl butoxide (PBO). If you are certified organic, check with your certifier before using it.

On resistance: natural pyrethrins don’t have the resistance problems pyrethroids do. Py-Bo is a contact spray, so it has to hit the insect to kill it. If you’re not getting the kill rate you want, change the spray application, direction and droplet size. That’s what makes the difference.

For strawberry-specific spray set-up, see our New Zealand thrips on strawberries page.

Buy Py-Bo: 250 mL, 1 L, 5 L or 20 L, or ask at Nutrien Ag, E.E. Muir, Elders, Lindsay Rural or Fernland.

FAQ

What is intonsa thrips?

Frankliniella intonsa is a flower thrips found across Europe, Asia, New Zealand and North America. It was confirmed in Australia for the first time in April 2026 on a berry farm at Elimbah in south-east Queensland.

Is intonsa the same as “New Zealand thrips”?

“New Zealand thrips” is a nickname some Queensland growers use for intonsa, because it has been a pest in New Zealand since 2002. It is not the same as New Zealand flower thrips (Thrips obscuratus), which is a different species.

How do I know if I have intonsa or western flower thrips?

You can’t reliably tell by eye. The main difference is the length of the short hairs behind the eyes, which needs a microscope. Send flower samples to an entomologist, or call the Exotic Plant Pest Hotline on 1800 084 881 if you suspect a new pest.

What crops does intonsa attack?

In Queensland it has damaged strawberries, raspberries and blackberries. Overseas it attacks many vegetables, including beans, cucurbits and capsicum, plus cotton, lucerne, cut flowers and ornamentals.

Can I use Py-Bo on thrips?

Yes. Thrips are named on the Py-Bo label for fruit and vegetable crops, cut flowers and ornamental plants, at 1 mL per litre with a 1-day withholding period on edible crops. It is a contact spray, so coverage decides the result. Do not spray plants in flower while bees are foraging.

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