Spray coverage for whitefly and earwigs: how to hit Py-Bo contact pests

Contact spray only kills the insect a droplet hits. Whiteflies sit on the undersides of leaves. Earwigs hide in bunches, bark and litter. Thrips and aphids are on the label too — thrips tuck into new growth and flowers; aphids sit on the tips, but curled leaves still hide them. If those surfaces stay dry, live pests remain. That is a coverage problem, not a rate problem.

This page is for commercial Australian growers and anyone searching spray coverage, whitefly spray, earwig spray, underside coverage or pyrethrum bioassay. It keeps the coverage test from the old “How good are you at killing insects?” page and turns it into an on-label grower page. Product discussed: Py-Bo Natural Pyrethrum Insecticidal Concentrate (APVMA 53738; 80 g/L pyrethrins + 320 g/L piperonyl butoxide, EC). Always read the current APVMA-approved label. The label is the law.

Whiteflies and earwigs are named pests on the Py-Bo label (APVMA 53738) for fruit and vegetable crops, cut flowers and ornamental plants. So are aphids, thrips, leafhoppers, ants, and cabbage moth and other caterpillars. Use only the crops, pests and situations named on the current label. This page does not authorise off-label use.

Olive lace bug (OLB) and Monolepta (red-shouldered leaf beetle) are not named on the Py-Bo horticultural list. The old page used them as coverage examples. They are not labelled uses. If they are mentioned below, it is only to say they are not on the label.

Identification: where the spray has to land

Know the pest, then know the surface. Leaves and insects are often waxy. Droplets that look “wet enough” from the tractor can still miss the insect.

Whiteflies (on-label)

The label names whiteflies, not one species. In Australian horticulture the usual pests are greenhouse whitefly (Trialeurodes vaporariorum) and silverleaf whitefly (Bemisia tabaci, often called biotype B / MEAM1). Adults are tiny (about 1–1.5 mm), moth-like, white-waxed wings. Shake a leaf and you get a small white cloud. Eggs, crawlers and nymphs sit on the underside. After the first moult, nymphs settle, go scale-like and stop walking. Honeydew and sooty mould on leaves and fruit are often what you notice first.

Silverleaf whitefly holds its wings in a tent. Greenhouse whitefly wings sit flatter and overlap. Both are underside jobs. Adults and young nymphs are the stages a foliar contact spray can hit — if the underside is wet. Eggs and pupae are much harder. Disturbed adults fly off the leaf before the boom arrives.

Earwigs (on-label)

The label names earwigs. The horticultural pest in southern Australia is usually the European earwig (Forficula auricularia): dark brown, 12–24 mm, pincers at the rear (males curved, females straighter). Nocturnal. By day they hide in soil, rough bark, leaf litter, corrugated cardboard, and — once bunch fruit fills — inside the bunch.

On cherries, tomatoes and grapes they leave the soil or bark and live in the bunch: feeding without commuting. Damage is chewed stems (cherries can drop), shallow feeding on ripening fruit, and contamination at pick. A spray that only wets the outside of a tight bunch does not contact the earwig in the middle. Night or dusk is when they move; that is also when you can hit them outside the hide.

Thrips and aphids: undersides and hiding places (on-label)

The label names thrips and aphids. Coverage still decides the kill.

Aphids sit out on growing tips, flowers and young leaves. That is the easy surface — until the flush curls and the colony is inside the curl. Honeydew, ants and sooty mould follow. Live young; a generation can turn over in about a week in warmth.
Thrips are mostly on new growth. They also hide further inside flowers (western flower thrips did not get that name by sitting on the upper surface). Chilli thrips and others feed on undersides of young leaves, buds and fruit. Eggs are inserted in tissue: a contact spray does not kill those. Pupae are often off the crop.

Other labelled horticultural pests have the same geography. Leafhopper nymphs wander on tender shoots; adults fly. Surface caterpillars sit down in the foliage by day and are higher and more exposed after dark. Ants on honeydew are on the canopy if you hit them — not a nest treatment. None of that replaces wetting whitefly undersides or opening the earwig bunch.

Contact versus not

Py-Bo kills by contact. If the droplet does not hit the insect, the insect does not die. It is not systemic. It is not residual in the plant. UV breaks pyrethrins down in a few hours of sunlight — that is why the withholding period is one day, and why you re-treat on the next hatch, not on a six-week “protection” interval.

Pest / stage	On Py-Bo horticultural label?	Hit by a foliar contact spray?
Whitefly adults	Yes (whiteflies)	Yes, if undersides are wet. Disturbed adults often fly off
Whitefly young nymphs / crawlers	Yes	Yes, if the underside is actually wet
Whitefly eggs and pupae / settled late nymphs	Named as whiteflies, not as every stage	Eggs and pupae: much harder. Late nymphs are scale-like and easy to miss
Earwigs in bunches, bark, litter	Yes (earwigs)	Yes, if droplets reach into the bunch or hide. In soil or deep litter: no, unless that site is wet
Aphids on tips and young leaves	Yes	Yes, if contacted. Inside tightly curled flush: much harder
Thrips on new growth, flowers, undersides	Yes	Yes, if coverage reaches tips, flower insides and undersides. Eggs in tissue: no. Pupae off-crop: no
Leafhoppers (nymphs and adults)	Yes	Yes, if contacted. Adults hop or fly out of the spray
Exposed caterpillars	Yes (cabbage moth and other caterpillars)	Yes, if larvae are on the surface and hit. Inside heads, fruit or stems: no
Ants on the canopy	Yes	Yes, workers if hit — not a nest treatment
Olive lace bug (OLB)	No	Not a registered claim. An underside feeder — same physics as whitefly, not a labelled use
Monolepta / red-shouldered leaf beetle	No	Not named. Fly-in beetles after spring rain are not a Py-Bo pest claim
Scarabs, Christmas beetles, Rutherglen bug	No	Not named horticultural pests on this label
Scales, mealybugs, pests inside tissue	No	No — wax sheds water-based spray; contact cannot reach inside fruit, mines or galls

How to spray Py-Bo (1 mL/L, 1-day WHP)

Product: Py-Bo Natural Pyrethrum Insecticidal Concentrate (APVMA 53738)
Actives: 80 g/L pyrethrins + 320 g/L piperonyl butoxide (PBO), emulsifiable concentrate
Mode: contact only. Knockdown of insects the spray actually hits. Not systemic. Not residual in the plant. Pyrethrins break down rapidly in sunlight.
Labelled horticultural situation: fruit and vegetable crops, cut flowers and ornamental plants. Confirm your crop on the current pack.
Labelled horticultural pests: aphids, ants, cabbage moth and other caterpillars, earwigs, leafhoppers, thrips, whiteflies.
Rate on that labelled horticultural use: 1 mL Py-Bo per 1 L water, or 100 mL per 100 L water (1 L per 1,000 L). Do not invent another rate.
Withholding period: 1 day on labelled edible plants (do not harvest for 1 day after application). Spray today, pick tomorrow where the label allows. Confirm crop listing and WHP on the current label.
Re-entry: once the last droplet has settled, workers can re-enter. That is not a bee-safe claim.

Mix 1 mL/L (100 mL/100 L) in clean water only if that is the rate on the label for your situation.
Apply so droplets contact the pest: undersides for whiteflies (and for thrips/aphids that sit there); into bunches, bark and hiding places for earwigs; tips and flower insides for aphids and thrips. Thorough coverage of all foliage, including undersurfaces, is what the horticultural use requires.
Prefer dusk / after dark. Do not spray plants in flower while bees are foraging.
If live labelled pests remain after the spray has dried, they were not contacted — or they flew, hopped or dropped out of the way. Change volume, droplet size or nozzle angle on a test run (see the bioassay below).
Follow up when the next hatch is visible. Whitefly eggs and thrips eggs survive the first pass. Aphids can rebuild in about a week. Earwigs still in soil or the next bunch were not hit.

You can tank-mix a labelled Py-Bo spray with a fungicide or foliar fertiliser only if every product in the tank allows it. That does not change the 1 mL/L Py-Bo rate, and it does not replace coverage. Wetters and stickers are not required for Py-Bo. Change droplet size, angle and volume first. If you still want to compare a wetter on a test row, check compatibility of every product and do not treat a wetter as a substitute for hitting the underside or the bunch.

Py-Bo is APVMA-approved for listed uses. Use only on crops, pests and situations named on the label. This page does not authorise off-label use.

The coverage bioassay (keep this test)

Yellow water-sensitive papers tell you whether droplets landed. They do not tell you whether the insect died. Py-Bo knocks labelled contact pests in minutes, so you can read the result before you spray the rest of the block. That is the point of using it as the test: dead insects mean contact; live insects mean you missed.

Droplet size, angle and volume

Aerosol-fine droplets may never land. They are so small they float. A layer of air around the drop stops them “crashing” into a leaf, so they drift until they evaporate. Mist-sized droplets still float, but mostly downwards. On the way they can meander in air currents around and under leaves — which is how you wet a whitefly underside. Orchard air-blast can force that mist to impact further into the canopy as the air slows. Bigger, spray-sized droplets use more litres per tree and often give less contact per litre. There is always a mix of sizes; the setting you choose is the one you are testing.

You can tinker with droplet size, nozzle angle, air speed and litres per tree (or per row of veg). Mature canopy is not a young tree. Both sides of the row: some spray should get through — or not, which is the problem. Nozzles aimed only at the upper surface will miss whiteflies. A boom that never opens a cherry or tomato bunch will miss earwigs.

How to run the test

Find a patch where labelled pests are busy — the last two trees in a row, or a couple of infested plants at the end of a greenhouse bay. Do not start on the whole block.
Mix Py-Bo at the labelled horticultural rate: 1 mL per 1 L (1 L per 1,000 L of water).
Use the setting you have been using, or the one you think you should be using. Spray both sides. Stop.
Get off and look within about 15 minutes. You are scoring insects, not the shine on the leaf.
Death stages on insects that were hit: excitation, convulsion, paralysis, death. Small insects (aphids, thrips, whiteflies, small nymphs) can already be dead or twitching slowly. Caterpillars may have bailed out and hang on silk. Leafhoppers and whitefly adults that were excited may have left — check the ground for larger insects still in excitement or paralysis. You can pick a few into a cap or paper bag to confirm they finish dying.
Judgement: if they are all dead or affected, coverage is adequate (or overdone). If some labelled pests are unaffected, they were not contacted. Are they under the leaf? Down in the skirt? In the middle of the bunch? Inside the flower? Adjust droplet size, angle, velocity or volume, then do another couple of trees or plants. A third set if you need it.
If everything is dead, you cannot kill them any deader. You may be using more litres than you need. Try less volume or a finer mist and confirm on the next test pair. Once it is right, that cost and that coverage stay with the block.

Unaffected pests are a physical miss. Change something physical. Do not bump the mixing rate above the label to “make up” for dry undersides.

Dusk versus bees

Pyrethrins are dangerous to bees. The Py-Bo label says do not spray any plants in flower while bees are foraging. Apply after dark, when bees are in the hive. Residues continue to keep bees off treated surfaces into the next morning until UV degrades the pyrethrins (often around mid-morning). Do not treat Py-Bo as bee-safe in daylight on open flowers.

Dusk or last light also matches the pests. Earwigs come out of bunches, bark and litter after dark. Caterpillars sit higher once birds have gone. A late-arvo or night spray gives the pyrethrins the hours before sunlight breaks them down. Whiteflies and aphids are still on the leaf at night — you still have to wet the underside.

Contact spray will also knock beneficials it hits (ladybirds, lacewings, hoverfly larvae, Orius, parasitoids). Because residues degrade in a few hours of UV, you can re-introduce beneficials onto a lower pest population once the pyrethrins are gone. Use Py-Bo as a knockdown or harvest-close flush, not as a weekly cover spray over an IPM program.

FAQ

Are whiteflies and earwigs on the Py-Bo label?

Yes. The current public horticultural pest list on APVMA 53738 is aphids, ants, cabbage moth and other caterpillars, earwigs, leafhoppers, thrips and whiteflies, on fruit and vegetable crops, cut flowers and ornamental plants. Whiteflies and earwigs are named. Confirm the current pack. This page is about getting droplets onto those named pests. It is not a claim for every insect that ever sat on a leaf.

Is olive lace bug or Monolepta a labelled Py-Bo use?

No. Olive lace bug (OLB, Froggattia olivina) and Monolepta (red-shouldered leaf beetle, Monolepta australis) are not named on the Py-Bo horticultural list. The old coverage article used OLB as an underside example and Monolepta as a fly-in beetle after spring rain. Same physics — underside or a beetle on the leaf — is not a registration. Do not treat this page as an OLB or Monolepta claim. Named crops and named pests only.

Why do I still have live whiteflies after I sprayed?

They were not contacted, or you hit adults and left eggs and settled nymphs on a dry underside. Turn leaves. If the underside is dry, change nozzle angle, air, volume or droplet size and re-run the bioassay on a couple of plants. Adults that flew up as you arrived were not in the spray. Follow up when the next hatch is visible. Do not raise the rate above 1 mL/L to compensate.

How do I get earwigs in bunches?

Wet the inside of the bunch, not just the outside, and time the spray for dusk or night when they leave the hide. Daytime they are in soil, bark, litter or the tightest part of the bunch. Thinning to singles, opening the canopy and pulling prunings away from the trunk reduces harbour. Contact still has to reach the insect. Earwigs in soil are not a foliar kill.

Where do I aim for thrips and aphids?

Aphids: growing tips, flowers and young leaves — then the underside and the inside of any curled flush. Thrips: new growth, flower insides, undersides of young leaves, calyx and fruit-touch points. Eggs in tissue and thrips pupae off the crop survive the first pass. That is why a follow-up on hatch is normal.

What rate of Py-Bo, and what is the withholding period?

On the labelled horticultural use: 1 mL per 1 L of water (100 mL per 100 L, or 1 L per 1,000 L). The withholding period on labelled edible plants is 1 day. Always confirm the crop, pest and WHP on the current APVMA-approved label. Do not invent rates.

Do I need a wetting agent?

Not for Py-Bo. Wetters and stickers are not required; they add cost for no stated benefit. The old page suggested comparing a smidgen of wetter because leaves and insects are waxy. If you test one, keep it as a side-by-side on a couple of plants, check tank-mix labels, and still fix angle, droplet and volume first. A wetter will not crawl into a dry bunch or a missed underside for you.

Will one spray clean them up for the season?

No. Py-Bo is a contact knockdown with no residual. Whitefly eggs, thrips eggs in tissue, aphids in a missed curl, and earwigs still in soil or the next bunch keep the cycle going. Plan a follow-up when the next hatch or fresh insects are visible, and keep walking undersides and bunches.

When should I spray so I do not kill bees?

Do not spray any plants in flower while bees are foraging. Apply after dark when bees are in the hive. Residues keep bees off treated surfaces into the next morning until UV degrades the pyrethrins. Do not treat it as bee-safe in daylight on open flowers. Dusk also suits earwigs.

Quick reference

Hub pests (on-label): whiteflies; earwigs; coverage also for thrips and aphids (undersides, tips, flowers, bunches)
Also on the horticultural list: ants, cabbage moth and other caterpillars, leafhoppers
Whiteflies: greenhouse whitefly Trialeurodes vaporariorum; silverleaf whitefly Bemisia tabaci — undersides; honeydew and sooty mould; adults and young nymphs hittable if wet
Earwigs: European earwig Forficula auricularia — nocturnal; soil, bark, litter, then bunches (cherries, tomatoes, grapes); spray must enter the bunch
Aphids: tips and young leaves; curled flush hides them; live young; generation ~1 week
Thrips: new growth, flower insides, undersides; eggs in tissue not killed; pupae often off-crop
Not claimed: olive lace bug (OLB), Monolepta, scarabs / Christmas beetles, Rutherglen bug, scales, pests inside tissue
Bioassay: 1 mL/L on a couple of infested trees or plants, both sides; read knockdown in ~15 minutes; adjust droplet, angle, volume; do not raise the rate
Spray: Py-Bo 1 mL/L or 100 mL/100 L; contact; 1-day WHP; undersides and bunches; dusk vs bees; follow-up on hatch
Product: 80 g/L pyrethrins + 320 g/L PBO; APVMA 53738; fruit and vegetable crops, cut flowers and ornamental plants

Always read and follow the current APVMA-approved label. The label is the law. Named crops and named pests only. Py-Bo is available through Pestech Australia’s Ag resellers or direct.