Liriomyza sativae: first record in Greece, life cycle, hosts and management

The life cycle of Liriomyza sativae, from the egg inside the leaf to the puparium in the soil — Figure 1The cycle closes in fifteen days at 30 degrees and in twenty five at 15. The decisive place is not the leaf but the soil, where the third instar drops and pupates a few centimetres below the surface.

Savvas Pastopoulos, Agronomist MSc, Pastopoulos Agronomics, Neos Mylotopos, Pella, Greece

On 20 October 2026 the first record of Liriomyza sativae in Greece was announced, on a leaf sample of Gypsophila from a cut flower holding in the Attica Islands regional unit, identified by the Benaki Phytopathological Institute [1]. It is a Union quarantine pest, and the fourth leafminer of the genus to reach the country. This text describes the life cycle, the hosts and the symptoms, explains why spraying on its own has failed wherever it has been tried, and records what the earlier Greek experience with a related species showed.

15 daysthe full cycle at 30 degrees, against 25 days at 15

18 familiesof plants, with more than 60 hosts

200 to 700eggs per female, at 30 to 40 a day

1992the year another leafminer entered Crete and covered the island within one year

Contents

What was found, where, and what quarantine status means
The life cycle
Hosts and symptoms
The causes of insecticide spray failure
Management in practice
Sources

1. What was found, where, and what quarantine status means

The record was made on Gypsophila, that is on a cut flower crop and not on a vegetable, and that is not a detail. In the interceptions recorded by the European Food Safety Authority, across 624 cases from 1996 to November 2019, 39 per cent concerned cut flowers and branches with foliage and 56 per cent fruit and vegetables [2]. Ornamental trade is an established entry route, not a rare one.

The species is listed as a Union quarantine pest in Annex II, Part A of Implementing Regulation (EU) 2019/2072 [2]. That status has a consequence unlike any other pest: management is not the grower's choice but a matter for the competent authority, and the announcement asks explicitly for the service to be informed of any suspect or unusually heavy infestation, and of any failure of control with the usual products [1].

Until now, within the EPPO region L. sativae had been recorded in a few countries, among them Turkey, Israel, Jordan, Armenia and Malta [3]. Greece now joins that list.

The precedent of the Liriomyza huidobrensis invasion, 1992 It is not the first leafminer of the genus to enter the country. Liriomyza huidobrensis was first recorded in the middle of autumn 1992 in Crete, on greenhouse cucumbers, melons and beans, at sites in the Messara valley, at Filissia, at Platanias and at Kokkini Hani. Within 1993 it had spread across the whole island, and it was also found at Pyrgos and at Chalkida [4]. The same work recorded that the native parasitoids Diglyphus isaea and Dacnusa sibirica were already attacking the new leafminer.

The Greek experience therefore gives two things at once, and both are useful. That the spread of such an insect within a greenhouse zone is measured in months rather than years, and that the local parasitoid complex recognises the newcomer almost at once.

Sources: 1 2 3 4

2. The life cycle

The female pierces the leaf epidermis with the ovipositor and places the egg inside the leaf tissue. The egg is about 0.25 mm long and hatches in two to eight days depending on temperature [2][3].

Three larval instars follow, all feeding inside the leaf between the two epidermes, and lasting four to seven days in total. The larva grows from half a millimetre to three. At the end of the third instar it leaves the leaf and drops to the soil, where it pupates a few centimetres below the surface. The pupal stage lasts seven to fourteen days at 20 to 30 degrees [2][3].

Stage	Where it sits	Duration	What it means for management
Egg	Inside the leaf tissue	2 to 8 days	Protected from a contact spray
Larva, three instars	Inside the leaf mine	4 to 7 days	Only what crosses the lamina reaches it
Puparium	In the soil, a few centimetres deep	7 to 14 days at 20 to 30 degrees	Out of reach of any foliar spray
Adult	On the foliage	Up to a month	The only stage that traps can monitor

The full cycle closes in about 25 days at 15 degrees and about 15 at 30 [2]. The lower development threshold lies between 4.6 and 7.9 degrees depending on the stage [2]. The adult is sexually active one day after emergence and lives up to a month. Each female lays 200 to 700 eggs, at 30 to 40 a day, declining with age [2].

Adult Liriomyza sativae in lateral view — Figure 2Adult *Liriomyza sativae*, as identified in the source of the photograph. The yellow frons, the dark thorax with the yellowish scutellum and the hyaline wings are visible. These features are common to the whole genus and are not sufficient for separating the species, which is done in the laboratory only. Image: Forest and Kim Starr, licence CC BY 3.0 US, via Wikimedia Commons.

Why the generations overlap With a fifteen day cycle, an adult that lives a month and egg laying that continues through almost all of its life, every stage is present at the same time in a warm climate [2]. There is therefore no window in which the whole population sits in one vulnerable stage, and that is the core of the difficulty.

Cold tolerance decides what happens in winter. The puparium is the overwintering stage, and for four day old puparia the time to 50 per cent mortality is about nine days at 0 degrees, two days at minus 5 and less than one hour at minus 10 [2]. In a greenhouse and in a coastal zone those values are almost never reached in the soil.

Sources: 2 3

3. Hosts and symptoms

The host list covers more than 60 species in 18 botanical families, among them Solanaceae, Cucurbitaceae, Fabaceae, Asteraceae, Brassicaceae, Apiaceae, Amaranthaceae, Caryophyllaceae, Malvaceae, Liliaceae and Poaceae [2]. The Greek announcement names as main hosts tomato, pepper, aubergine, potato, cucumber, melon, watermelon, squash, bean, pea, lettuce, cabbage, cauliflower, cotton, Allium species, gypsophila, chrysanthemum and gerbera [1]. In the United States and in South America it is regarded as the most damaging agromyzid, with recorded yield losses of up to 80 per cent on celery in Florida and on lucerne in Argentina [3].

The symptoms are of three kinds and appear in this order. First the feeding and oviposition punctures of the adult female, round white specks on the leaf surface, the oviposition punctures being smaller and rounder. Then the larval mines, irregular and serpentine, whitish yellow, with dark frass along their edges. Finally the loss of photosynthetic area, which under heavy infestation reaches premature leaf fall and the death of young plants [1][3].

The mine does not identify the species The symptoms of L. sativae cannot be separated by eye from those of L. trifolii, L. huidobrensis and L. bryoniae, which are already present in the country, and identification requires laboratory examination [1]. The adult is one to three millimetres long and the separation rests on colour characters of the head and the thorax. In practice this means that nobody can state the species from a photograph of a mine, and that the sample goes to the service.

The three species already present in Greece are covered in the article on cucumber pests and diseases, together with the greenhouse monitoring data.

Sources: 1 2 3

4. The causes of insecticide spray failure

The dominant strategy against the species internationally has been the extensive use of insecticides, and the outcome is on record: L. sativae develops resistance readily, unlike its parasitoids [3]. The assessment by the European Food Safety Authority notes that many insecticides are no longer effective and that they damage the natural enemies at the same time [2].

The reason is structural and follows from the cycle itself. Of the four stages, three are out of reach of a foliar spray: the egg inside the tissue, the larva inside the mine, the puparium inside the soil. Only the adult is exposed. That is why international practice rests on products with translaminar activity, which reach the larva by crossing the lamina [3].

The second part is that spraying hits the regulator disproportionately. More than 140 parasitoid species are known for the genus Liriomyza, and they are the main means of control [3]. When their population collapses, the leafminer is released from its natural pressure and reaches levels it would not reach without intervention. That mechanism is how a secondary insect becomes a primary one.

Sources: 2 3

5. Management in practice

Monitoring. The only exposed stage is the adult, and it is monitored with yellow sticky traps. The second measurement is a count of active mines per leaf at fixed positions, which shows the rate and not only the presence. A mine that has emptied does not count.

The soil. Because pupation happens a few centimetres below the surface, the soil under an infested crop is the store of the next wave. Removal of crop residues, avoidance of successive susceptible crops in the same greenhouse and management of volunteer hosts along the margins are measures that act where no spray reaches.

The parasitoids. In greenhouses the commercially available species of the genus Diglyphus control infestations effectively [3]. Diglyphus isaea and Dacnusa sibirica are already present in the Greek fauna and were attacking the previous leafminer from its first season [4]. The two species are described in the article on beneficial organisms, with their target stages and temperatures.

Planting material and cut flowers. Entry occurred through an ornamental holding, and the pathways recorded by the European Food Safety Authority are plants for planting, cut flowers and branches with foliage, fruit and vegetables, and soil or growing medium carrying puparia [2]. Inspection of incoming material is the measure with the highest return per unit of effort.

Notification. As a quarantine pest, every suspect finding is reported to the competent service. The announcement asks for notification also where control with the usual products fails, because that is precisely the first signal of a difference from the species already present [1].

Authorisations for leafminers by crop are held in the register of the Greek Ministry of Rural Development and Food, at fyto.plantprotect.gr, and are valid in Greece only. Choice of product, rotation of modes of action and compatibility with the parasitoids are judged case by case by the agronomist who sees the crop.

Sources: 1 2 3 4

6. Sources

The numbers in the text refer to the list below.

[1] Region of Crete, Directorate of Rural Development of the Heraklion regional unit (2026). Notice on the first record in Greece of the quarantine pest Liriomyza sativae, 20 October 2026, in Greek. Source for the place and the crop of the first record, for the identification by the Benaki Phytopathological Institute, for the list of main hosts, for the description of the symptoms, for the need for laboratory identification and for the request to notify the service.
[2] EFSA Panel on Plant Health (2020). Pest categorisation of Liriomyza sativae. EFSA Journal 18(3):6037. Full text. Source for the listing in Annex II Part A of Regulation (EU) 2019/2072, for the duration of the stages and of the full cycle, for the development thresholds, for fecundity, for the cold tolerance of the puparia, for the hosts in 18 families, for the pathways and the interception percentages, and for the loss of insecticide effectiveness.
[3] EPPO Global Database. Liriomyza sativae (LIRISA), datasheet. Source for the distribution within the EPPO region, for the dimensions and the duration of the stages, for the symptoms of the punctures and the mines, for the losses in Florida and in Argentina, for the more than 140 parasitoids of the genus, for the role of Diglyphus in the greenhouse, for translaminar activity and for the development of resistance.
[4] Roditakis N.E. (1998). First record of the South American leafminer Liriomyza huidobrensis in Greece. Entomologia Hellenica 12: 81-83. Full text. Source for the first record of L. huidobrensis in the middle of autumn 1992 in Crete on greenhouse cucumbers, melons and beans, for the sites in the Messara valley, at Filissia, at Platanias and at Kokkini Hani, for the spread across the whole island within 1993, for the findings at Pyrgos and at Chalkida, and for the presence of the native parasitoids Diglyphus isaea and Dacnusa sibirica.

Disclaimer This text is informative and does not replace an on site assessment. It recommends no product and no active substance. Liriomyza sativae is a Union quarantine pest, so every suspect finding is reported to the competent plant health service and management follows its instructions. Identification of the species is carried out only in the laboratory, by the competent authority. Any use of plant protection products follows solely the authorisations of the Greek Ministry of Rural Development and Food and the label, and those authorisations are valid in Greece only and do not concern other countries. Foliar sprays on crops carrying fruit can cause spotting on the fruit and scorching of the foliage, so a test on a limited area with the same product and the same rate precedes the application, with five to seven days of waiting, and the spray is applied in the evening or early in the morning, never in a heatwave and never on foliage under water stress. Every intervention is carried out under the responsibility of the user, following an on site assessment by a licensed agronomist. Pastopoulos Agronomics accepts no liability for the use of this information.