Whiteflies
Whiteflies pose a serious threat to crops, causing direct damage and acting as vectors for viruses. Their control requires integrated strategies and modern technologies to ensure timely prevention and effective management.
Introduction
Whiteflies are insects belonging to the order Hemiptera and cause significant damage to a wide range of cultivated plants.
They possess piercing-sucking mouthparts capable of penetrating plant epidermal tissue and feeding on the phloem sap the conduits through which photosynthetic products circulate.
The whitefly life cycle includes six biological stages: egg, four larval instars, and the adult stage.
The immature stages are largely immobile and progress through successive molts as they grow, shedding their exoskeleton in a process known as ecdysis.
The adult stage is winged and capable of reproduction, with a lifespan ranging from a few days to a month, depending on the species.
Environmental conditions, particularly temperature, greatly influence their life cycle, which typically spans one to two months.
A key characteristic of whiteflies is the production of honeydew, particularly by the larvae a sugary excretion that promotes the growth of sooty mold fungi (Capnodium spp., Cladosporium spp., Antennariella spp.).
These fungi form a black coating on leaves and fruit surfaces, commonly referred to as sooty mold complexes.
The damage caused by whiteflies varies depending on the species and the host crop. The most common impacts include:
Weakening of plants due to the extraction of organic compounds produced during photosynthesis.
Reduction in photosynthetic capacity caused by the growth of sooty mold on leaf surfaces.
In addition, several whitefly species are important vectors of plant viruses, spreading diseases that further reduce crop yields and quality.
Why Whitefly Problems Are Escalating
Several key factors contribute to the increasing prevalence of whitefly infestations:
- Excessive use of broad-spectrum pesticides, which promotes insect resistance and disrupts natural biological control mechanisms (e.g., beneficial insects, entomopathogenic fungi).
- Climate change, with rising average temperatures and milder winters, creating favorable conditions for whitefly reproduction and survival.
- Introduction of invasive species facilitated by global trade and movement of plant material.
Whiteflies Affecting Citrus Crops in Greece
In Greece, three whitefly species have caused significant economic damage to citrus crops over the past decades:
- Aleurothrixus floccosus (Woolly whitefly): This species caused severe outbreaks in nearly all citrus-growing regions during the early 1990s. The issue was brought under control through the gradual and systematic release of the parasitoid Cales noacki, under the guidance of the Benaki Phytopathological Institute. A related species, A. trachoides, which affects solanaceous crops, is a known vector of Duranta leaf curl virus (DLCV) impacting tomatoes, peppers, and potatoes.
- Aleurocanthus spiniferus (Asian spiny whitefly): This invasive species was first detected in Epirus in the mid-2010s, causing serious yield losses due to heavy sooty mold coverage on fruit surfaces. It has since spread to Aetolia-Acarnania and, more recently, to Achaia and Argolida, with a consistent expansion rate.
- Dialeurodes citri (Citrus whitefly): This species was identified in the early 2010s in the Iardanos region of the Elis Prefecture, affecting over 1,000 hectares of citrus groves. It weakens trees and drastically reduces fruit quality and market value due to the formation of sooty mold on the fruit. In many cases, the affected produce is either discarded or diverted to low-priced juice production. More recently, this species has been identified as a vector of Citrus yellow vein clearing virus, an emerging disease of global concern with severe impacts on citrus production.
To address this critical challenge, the Virology Laboratory of the Plant Protection Department in Patras (Hellenic Agricultural Organization – ELGO-DIMITRA) initiated targeted actions in collaboration with regional authorities in Western Greece.
These efforts led to the submission and approval of a technical project proposal under the Rural Development Programme (RDP, Submeasures 16.1 and 16.2), which enabled the implementation of effective control strategies.
The upcoming updates will provide a summary of the issue and outline the core strategies being implemented under the project to manage whitefly infestations in citrus crops.
News & Publications
Stay informed with articles and updates covering a wide range of topics from citrus cultivation practices to current pest management challenges.
Επιχειρησιακή Ομάδα
The operational group responsible for the project implementation includes:
- The Virology Laboratory of the Plant Protection Department – Patras, ELGO–DIMITRA
- Citrus Growers’ Cooperative of Iardanos
- A network of independent citrus growers
