Identify before you treat
A fungicide does nothing to a mite, and a broad-spectrum insecticide will make a mite problem dramatically worse by killing its predators. Guessing costs more than a hand lens.
Free diagnostic tool
Something is wrong
Something is wrong
with your plant.
Tell us which part is affected and what you can actually see. We narrow sixteen of the most common problems in this region down to the likely candidates — with the organic treatment first, the chemical option if it comes to that, the right booster for recovery, and how to stop it happening again.
1 · Where
Pick the affected part — leaves, stems, roots, trunk, fruit or the whole plant.
2 · What
Pick what you can see. Spots, webbing, wilting, holes, yellowing, sawdust, galls.
3 · Narrow it
Filter further by cause type, or search your plant by name to see what commonly attacks it.
4 · Treat it
Organic route first, chemical only if that fails, plus the booster that helps it recover.
Possible causes
Before you spray anything
Six rules that prevent most damage
Spray at dusk, never midday
Oils and neem burn leaves in strong sun, and midday spraying kills foraging bees. Evening application also gives the product all night to work.
Rotate modes of action
Using the same active ingredient repeatedly breeds resistance within two or three seasons. Alternate chemical groups, and lean on cultural control between rounds.
Cover the leaf undersides
Mites, aphids, scale and whitefly all live underneath. A spray that only wets the top of the leaf is money poured on the ground.
Respect the harvest interval
Every product has a pre-harvest interval printed on the label. On food crops it is not advisory. Write the spray date on a label tied to the plant.
Check watering first
A genuinely large share of "diseases" we are called out to are over-watering, compaction or a buried root flare. Rule those out before you buy anything.
Recovery
Boosters, and what each one is actually for
Treatment stops the damage. Recovery needs the right input — not a general-purpose fertiliser applied hopefully.
| Booster | Use it when | How it helps | Rate & frequency |
|---|---|---|---|
| Seaweed extract | After any pest damage, transplant shock or heat stress | Cytokinins and trace elements push new leaf and root growth; measurably improves heat tolerance | 3–5 ml/L foliar, fortnightly |
| Mycorrhizal inoculant | At planting, and during root-rot recovery once new white tips appear | Extends the effective root system many times over for water and phosphorus uptake | Once, into the planting hole |
| Humic & fulvic acid | Compacted, tired or over-fertilised soils | Improves structure and unlocks nutrients already present but bound up in the soil | 2 ml/L drench, monthly |
| Chelated iron (EDDHA) | Yellow new leaves with green veins on blueberry, citrus, camellia | Delivers iron that stays available even above pH 7, where ordinary iron locks up | Label rate, repeat at 6 weeks |
| Calcium nitrate | Blossom end rot on tomato, pepper, aubergine | Supplies calcium directly to fruit while you fix the underlying watering inconsistency | 2 g/L foliar, weekly |
| Potassium silicate | Recurring mildew, sap-sucking pests, heat stress | Silicon stiffens cell walls, making leaves physically harder to penetrate or feed on | 1–2 ml/L, weekly in season |
| Sulphate of potash (0-0-50) | Fruiting and flowering stages; soft, disease-prone growth | Hardens tissue, improves fruit quality and drought tolerance without pushing soft new leaf | 2 g/L, fortnightly |
| Compost tea | Ongoing, as prevention on any bed | Introduces competitive microbes that occupy leaf and root surfaces before pathogens can | Monthly drench + foliar |
| Trichoderma harzianum | Damping off, early root rot, replanting into a sick bed | A beneficial fungus that parasitises soil pathogens and colonises the root zone first | Drench at sowing, repeat at 4 weeks |
| Elemental sulphur | Soil pH too high for blueberry, camellia or azalea | Gradually acidifies soil so iron and manganese become available again | Per soil test, autumn application |
Do not feed a plant that is collapsing. Fertiliser applied to a root-rotted or
badly wilting plant burns what roots remain. Fix the water, the drainage or the pest first — then feed,
starting at quarter strength once new growth appears.
Safety
If you do reach for a chemical
We list chemical options here because sometimes an organic programme genuinely fails and a crop is worth saving. That does not make them casual purchases.
- Read the whole label before you buy, not after you open it
- Wear gloves, long sleeves and eye protection — every time
- Mix outdoors, only what you will use in one session
- Never spray in wind, or within two days of expected rain
- Keep people, pets and beehives off the area until it has dried
- Observe the pre-harvest interval to the day on anything edible
- Never decant into a drink bottle. This is how children get poisoned
- Dispose of surplus and containers through municipal chemical waste, never down a drain
Product availability and legal approval vary by country and change over time.
Active ingredients named on this page are listed for identification. Always confirm the product is
currently approved in Japan for your specific crop, and follow the label — the label is the law.
🐝 Protect pollinators
Never spray open flowers. If a plant is in bloom and must be treated, do it after dusk when bees have stopped foraging, and choose a product with a short residual.
🐟 Protect waterways
Beppu drains to the bay. Never spray near an open drain, never rinse equipment where the washings can reach a gutter, and leave an unsprayed buffer beside any watercourse.
🐛 Protect the good insects
Ladybirds, lacewings, hoverflies and predatory mites do a lot of unpaid work. Broad-spectrum sprays remove them first and the pest rebounds harder — this is the classic mite explosion.
📝 Keep a spray log
Product, rate, date, target and weather. Five minutes of writing tells you next season what worked, and stops you accidentally repeating the same chemical group.
Not sure?
Send it to us
Describe what you are seeing and we will tell you what it most likely is — and whether it needs a visit. There is no charge for an initial opinion.
Some things need eyes on them
Mature trees, bacterial wilt, borers and anything affecting a whole crop should be inspected in person. Our pest and disease visits start at ¥9,500 including a written treatment log.