Pre HLB

Mail to:

Mail to:

info@prehlb-blog.eu
Teléfono:

Teléfono:

+34 676 67 67 67
A THREAT FOR ALL CITRUS FRUITS

What is HLB?

Candidatus Liberibacter

What is it?

Citrus greening, also known as Huanglongbing (HLB) or yellow dragon disease, is a disease of citrus fruit caused by bacteria (Candidatus Liberibacter spp.) that live and multiply in the phloem of the tree. These bacteria are transmitted to other healthy trees by two psyllids, Diaphorina citri and Trioza erytreae, as well as by grafting with infected plant material.

The HLB disease is a major threat to citrus growing worldwide. This disease, described as the most devastating citrus disease, and for which there is currently no cure, reduces the yield and quality of the fruit, causing the death of the tree within 3-5 years. The economic and social impact of an eventual introduction of HLB in our citriculture would be of alarming dimensions, as attested by the cases of other producing regions in the world affected by this disease. For example, in Florida, the main citrus-producing region in the United States, the presence of HLB in just five years led to a 23% drop in productivity, economic losses estimated at more than 1.7 billion dollars and the destruction of more than 8,000 jobs directly and indirectly associated with this sector.

Although the HLB disease has not been detected in Europe to date, the situation in this region is now seriously threatened following the recent detection of Trioza erytreae in the Iberian Peninsula (northern Spain and Portugal).

There is currently no cure for the HLB disease, the best control strategy being the prevention of the disease. In this sense, information and awareness of farmers is of vital importance in the early detection of the vectors and/or the disease.

Two Vectors

How can we differentiate them?

CHARACTERISTICS OF

Trioza erytreae

The African citrus psylla, Trioza erytreae, has spread to the Iberian Peninsula and the archipelagos surrounding the African continent: Réunion, Mauritius, Madeira and the Canary Islands. Its presence in the Iberian Peninsula was confirmed in August 2014. In particular, this vector finds optimal conditions for its development in humid and temperate climates.

adults

Body length about 4 mm, initial colour light green, turning dark at maturity. Transparent wings, without spots, with very marked venation. Head and antennae black, except for the first segment which is whitish in appearance. When feeding, they adopt a very characteristic position, raising the body at an angle of 35º with respect to the food substrate.
NYMPHS

Yellowish in colour, flattened or oval in shape and surrounded by a band of waxy filaments.
eggs

They are yellowish and elongated, and are attached vertically to the leaf by a small stalk at one end.
CHARACTERISTICS OF

Diaphorina citri

The Asian citrus psylla, Diaphorina citri, is widely encountered in Asia, and in recent decades has spread throughout the Americas, the African islands of Réunion and Mauritius, and several archipelagos in Oceania. It is favoured by warm, coastal-influenced climates and is tolerant of high temperatures.            

adults

Body length about 3-4 mm, dark yellow colour. Light-coloured opaque wings with a characteristic broad brown longitudinal band. Like the African psylla, they adopt a very particular shape while feeding, raising the abdomen at a 45° angle to the plant substrate.
NYMPHS

Initially light yellow in colour, later evolving towards darker shades. Characteristically, they have highly developed wing primordia.
eggs

Yellow-orange, deposited on newly formed shoots, often on leaves at spearhead stage.
CHARACTERISTICS OF

Trioza erytreae

The African citrus psylla, Trioza erytreae, has spread to the Iberian Peninsula and the archipelagos surrounding the African continent: Réunion, Mauritius, Madeira and the Canary Islands. Its presence in the Iberian Peninsula was confirmed in August 2014. In particular, this vector finds optimal conditions for its development in humid and temperate climates.

adults

Body length about 4 mm, initial colour light green, turning dark at maturity. Transparent wings, without spots, with very marked venation. Head and antennae black, except for the first segment which is whitish in appearance. When feeding, they adopt a very characteristic position, raising the body at an angle of 35º with respect to the food substrate.
NYMPHS

Yellowish in colour, flattened or oval in shape and surrounded by a band of waxy filaments.
eggs

They are yellowish and elongated, and are attached vertically to the leaf by a small stalk at one end.
CHARACTERISTICS OF

Diaphorina citri

The Asian citrus psylla, Diaphorina citri, is widely encountered in Asia, and in recent decades has spread throughout the Americas, the African islands of Réunion and Mauritius, and several archipelagos in Oceania. It is favoured by warm, coastal-influenced climates and is tolerant of high temperatures.

adults

Body length about 3-4 mm, dark yellow colour. Light-coloured opaque wings with a characteristic broad brown longitudinal band. Like the African psylla, they adopt a very particular shape while feeding, raising the abdomen at a 45° angle to the plant substrate.
NYMPHS

Initially light yellow in colour, later evolving towards darker shades. Characteristically, they have highly developed wing primordia.
eggs

Yellow-orange, deposited on newly formed shoots, often on leaves at spearhead stage.
Gallery of images of

Trioza erytreae

Gallery of images of

Diaphorina citri