Problems and Solutions

The Citrus Whitefly Problem in the Regional Unit of Ilia

The citrus whitefly (Dialeurodes citri) has posed a severe threat to citrus cultivation in the Regional Unit of Ilia, leading to a substantial decline in production quality and, in many cases, total loss of income for local growers.

To address the issue, two operational action plans were submitted in 2019 and 2022 under the Rural Development Programme (RDP – Measures 16.1 and 16.2), with the aim of developing effective control methods for Dialeurodes citri.

These plans proposed improvements to Integrated Pest Management (IPM) through the adoption of advanced technologies, such as artificial intelligence (e.g., machine learning), big data analytics, real-time monitoring networks (RTM), and the development of diagnostic methodologies for in-field sample analysis. These topics are core areas of research at the Virology Laboratory of the Plant Protection Department in Patras, with several related studies published in reputable scientific journals (e.g., DOI:
10.3389/fmicb.2021.562199,
10.1089/omi.2018.0012,
10.1016/j.bsheal.2020.06.001,
10.1089/omi.2021.0090).
Notably, the AI-based diagnostic methodology has been awarded a national patent by the Hellenic Industrial Property Organization (OBI).

Επιστημονική έρευνα

Κατά την διάρκεια των επισκοπήσεων που ακολούθησαν, εκτιμήθηκαν η συχνότητα και το μέγεθος των προβλημάτων φυτοπροστασίας των εσπεριδοειδών της περιοχής, όπου ανάμεσα σε άλλα διαπιστώθηκε, εκτός του διαλευρώδους, και η συνεχής παρουσία του εριώδους αλευρώδους (Aleurothrixus floccosus) που προκαλεί διαφορετικού είδους προβλήματα.
Παράλληλα εξετάστηκαν με αρχικές προσεγγιστικές εκτιμήσεις τα ποσοστά παρασιτισμού διαφόρων βιολογικών σταδίων του διαλευρώδους από ωφέλιμα έντομα και εντομοπαθογόνους μύκητες. Με τα δεδομένα που συλλέχτηκαν αναπτύχθηκε στατιστικό μοντέλο βάσει του οποίου προγραμματίστηκαν τα απαραίτητα μέτρα φυτοπροστασίας, τα οποία εφαρμόστηκαν απαρέγκλιτα, μέσω συντονισμένων δράσεων, από τους παραγωγούς κατά το έτος της μελέτης αλλά και τις χρονιές που ακολούθησαν.

Τα αποτελέσματα κατά την εφαρμογή των δράσεων του προγράμματος ήταν θεαματικά, καθότι το πρόβλημα ελαττώθηκε κατά τα πρώτα στάδια εφαρμογής και έως σήμερα ελέγχεται πλήρως, με δραστική μείωση των ψεκασμών και άριστη παραγωγή προϊόντων

Ακολουθούν μερικά από τα αποτελέσματα της εργασίας.

Sampling Regions and Geographic Mapping

From the start of the program, annual sample collection was carried out across several locations in Ilia (Table 1), which are illustrated on the geographic heatmap (Figure 1). The color and size of the circles indicate the density of whitefly eggs detected during sampling.

Table 1: Sampling locations and coordinates

location	Location	lon	lat	n
Tραγανό	Tragano	21.3284	37.88479	20
Αλποχώρι	Alpochori	21.35669	37.7265	20
Αλποχώρι - Μεσσολογγακι	Alpochori - Messolongaki	21.35669	37.7265	40
Βούναργο	Bounargo	21.40066	37.72147	259
Κάτω Σαμικό	Kato Samiko	21.59151	37.5429	60
Καλυβάκια	Kalybakia	21.67685	37.63768	60
Λευκοχώρι	Leukochori	21.27637	37.86709	80
Λευκοχώρι Γαστούνης	Leukochori Gastounes	21.27633	37.86706	81
Ξυλοκέρα	Xylokera	21.39779	37.72589	61
Σαλμώνη	Salmone	21.51371	37.64789	58
Σαλμώνη Βίγκλα	Salmone Binkla	21.52288	37.64896	60
Σαλμώνη Γέφυρα	Salmone Gephyra	21.50628	37.64636	80
Σαλμώνη βολαντζέικα	Salmone bolantzeika	21.51179	37.64792	74
Τραγανό	Tragano	21.32531	37.88811	175

(Locations include Tragano, Alpochori, Bounargo, Kato Samiko, Leukochori, Salmone, and others.)

Figure 1

Geo-referenced map of whitefly sampling points.
The visual indicates infestation intensity based on egg counts.

Following the biological stage analysis of the insect populations across different areas, a synchronized spraying operation was planned. The intervention targeted regions based on the frequency of susceptible developmental stages (eggs, nymphs), as identified in the pre-treatment phase (Figure 2).

Figure 2

Sample map before the first coordinated spraying intervention.
Legend indicates total number and percentage breakdown of developmental stages (eggs and nymphs)

Figure 3

Before the first intervention, active stages of the pest were detected across nearly all sampling points. In the following years, field inspections, sample analyses, and targeted guidance for or against spraying continued systematically.

As of today, Dialeurodes citri is fully under control in the implementation areas of the Regional Unit of Ilia. Systematic monitoring, precision-guided actions, and farmer cooperation have rendered the pest a non-issue. Spraying has been minimized, and the quality of citrus products has returned to exceptional levels.