Nurseries in demarcated zones: how the Popillia duties work

The framework, and why it's all recent

Popillia japonica is a Union quarantine pest (Implementing Reg. (EU) 2019/2072) and sits on the list of priority quarantine pests (Reg. (EU) 2019/1702) — the strictest category the Union has.

The specific measures, though, are young: Implementing Regulation (EU) 2023/1584 dates from 1 August 2023, and Italy's national emergency plan was adopted by ministerial decree of 3 April 2024, no. 154311. Below that sit the regional action plans and the annual decrees that update zones and prescriptions.

Demarcated areas today cover Piedmont, Lombardy, Valle d'Aosta, Emilia-Romagna, Liguria, Friuli-Venezia Giulia and Veneto: they have grown out of a first 2014 outbreak in the Parco del Ticino, and they keep moving — in 2025 new outbreaks were found in Veneto and Liguria.

Why you won't find a checklist here

A list of duties valid for everyone doesn't exist, and anyone offering you one is doing you harm. The reason is structural: zone boundaries and operative prescriptions live in regional decrees, reissued every year.

A concrete example, and it comes from an official source. The document in which Piedmont's plant protection service explains the mandatory measures to nurseries refers, for the demarcated area, to directorial decree no. 853 of 11 November 2024. But Piedmont's demarcated area has since been updated by D.D. no. 965 of 4 November 2025. In other words: even the official guidance for nurseries is a cycle behind on the fact that matters most — whether you're in or out.

So take what follows as a conceptual map, with Piedmont's numbers as an example. Your region may set different windows and prescriptions, and the only valid reference is this year's decree where you are.

The key to all of it: the risk is the soil, not the plant

If you take one thing away, take this. The whole architecture of duties rests on a single fact: Popillia spends most of its life as a grub, in the soil. The adult chews leaves and is visible; the grub sits in the ground and isn't.

Everything follows. If a plant travels with soil, it can carry eggs and grubs with it unnoticed, over long distances. If it travels without soil, it can't. Which is exactly why plants moved bare root require no phytosanitary measure at all, and the same goes for plants grown under total physical protection — greenhouses closed to the ground, tunnels with intact netting.

Every other prescription serves one purpose: stopping females laying eggs in your growing medium. Read that way, the table of duties stops being bureaucracy and becomes obvious.

Four ways to grow, four regimes

The duties don't depend on what you produce, but on how you produce it. In Piedmont's scheme there are four families:

• Bare root — no phytosanitary measure. No soil, no risk.
• Total physical protection — no measures, provided the greenhouse is closed to the ground during the flight period and tears in the netting are repaired. A torn net is not a net.
• Pots outdoors — here they stack up: growing medium of commercial soil only (never field soil), mulch over the pot surface, isolation of the pot from the ground beneath, and, with adults about, a foliar treatment before movement.
• Field-grown with a root ball — the heaviest case: mulching or hilling up or repeated soil working, weeding the inter-row to discourage egg laying, and treatments tracking the flight.

Over all of it sits the calendar, and it isn't negotiable because it's the insect's: adults fly from late May to September, peaking in June-July; grubs sit in the soil from June until April-May of the following year. In Piedmont the mandatory measures run from 15 May to 30 September.

Three things almost everyone gets wrong

Piedmont's document holds three counter-intuitive points worth pulling out, because they're the ones where common sense leads you astray.

• Pheromone traps must NOT be used on the holding. It sounds absurd, and it is the official advice: the trap also draws in adults from outside and fails to catch them all, so it increases damage and egg laying inside the nursery. Put out a lure and you bring the problem home.
• The measures apply even if you sell inside the infested zone. If you hand plants to a business authorised to issue plant passports, that business can resell them outside: the chain doesn't stop at your gate, and the rule knows it.
• The perimeter doesn't end at your fence. Self-checks extend to the spontaneous plants around the holding, for a radius of at least 10 metres — and in some cases treatment covers a perimeter strip just as wide.

What you must be able to prove

The paperwork is what decides an inspection, and in Piedmont's scheme moving plants out of the infested zone rests on four pillars: at least one official annual inspection by the phytosanitary inspectors; at least two self-check inspections during the flight, recorded on a checklist; treatments logged in the field register; and purchase invoices for plant protection products kept on file.

And then there's the point that concerns us directly. After hilling up or working the soil, moving plants requires an official soil core sampling confirming the insect's absence from the growing medium, to be done by April. The useful window for finding grubs, by unpotting or coring, runs from autumn to the end of April.

On a finding, movement out of the zone is banned. One way out remains, and it's consistent with all the logic above: blocked plants can still be sold once reduced to bare root, or repotted with commercial soil. Remove the soil, remove the problem.

Where a nose actually helps

Read that last duty again: you have to prove absence of grubs in the soil, and you do it with cores. Coring is sampling: it looks in some spots, not all. If the outbreak is small and localised, the odds of hitting it with a handful of cores are what they are — and a lot blocked in autumn, after a whole season of measures, is a loss that follows you all year.

That is exactly the problem our work exists for: the dog covers the area and points out where to look, so the cores go to the right places instead of at random. It doesn't replace the official check — it carries no legal weight, and that should be said plainly — but it tells you what to expect before the inspector arrives, in a window (autumn to April) that matches the one when grubs can be found at all.

On how detection works, see our pages on Popillia japonica and on the method.

The most useful advice in this article

Don't trust this page. Not because it's badly written, but because legal content and web pages age at different speeds: the rule changes every year, the page stays. We've just seen that even an official regional document can point at a superseded delimitation.

The right party is your region's plant protection service, and the right document is this year's decree. What you'll find here is meant to get you to that phone call already knowing which questions to ask.