Citrus blackfly: how to manage

Approximately 30 species of whiteflies and black flies (Hemiptera, Aleyrodidae) are reported on citrus plants around the world, widely distributed geographically, surviving on a large number of wild and ornamental plants.

The citrus black fly Aleurocanthus woglumi Ashby (Aleyrodidae) originates from tropical and subtropical regions of Asia, spreading to Africa, North, Central and South America, the Caribbean and Oceania. It was first discovered in the Western Hemisphere in Jamaica (1913), then in Cuba (1916), Mexico (1935), Venezuela (1965) and French Guiana (1995).

The citrus black fly was found for the first time in Brazil, in July 2001, in Belém (PA) and has already been recorded in the states of Maranhão (2003), Amazonas (2004), Amapá (2006), Tocantins, Goiás and São Paulo (2008), Roraima (2009), Paraíba, Rio Grande do Norte, Pernambuco, Piauí, Bahia, Ceará, Minas Gerais (2010), Paraná, Rio de Janeiro and Espírito Santo (2011). Aleurocanthus woglumi was detected for the first time in the state of São Paulo, in March 2008, severely infesting orange, tangerine and lemon trees in the Artur Nogueira region, it spread to the north and northwest of São Paulo, reaching severe levels of attack and damage.

The pest infests more than 300 species of plants around the world, with citrus species being those most affected by the pest, including orange, tangerine and lemon trees, being indicators of its introduction into recently infested regions. In some regions of Brazil, jackfruit and mango trees (mainly Palmer) are severely infested by blackfly. Adults from A. woglumi they can be found in a large number of botanical species, in or around infested citrus orchards, such as in spontaneous or cassava plants, but without presenting postures or nymphs.

Direct damage is caused by the continuous suction of nutrients from the leaves and the consequent decline in plant vigor. Indirect damage comes from the appearance of sooty mold on leaves, branches and fruits. Sooty mold is formed by the growth of fungi on the sugary excretion of the citrus blackfly, which affects respiration and photosynthesis. The incidence of sooty mold also affects the quality of fruits for sale in natura, which require intensive washing during processing in the packinghouse.

Classified as a quarantine pest present (A2) in Brazil, the incidence of citrus blackfly also causes restrictions on the commercialization of host plants and their parts, originating from infested states and destined for states with no record of this species yet, requiring certification from the production area and declaration of pest-free departure.

The adults of A. woglumi They are dark gray in color and measure from 0,99mm to 1,24mm, with females being larger than males. The citrus blackfly lays in a spiral fashion on the lower surface of the developed leaves, with an average of 28 eggs per clutch (8-50 eggs), with an initial yellow-orange color. The cycle from egg to adult is 45 to 133 days (Figure 1). Females and males are winged and feed on shoots.

Natural enemies

Natural enemies are important components of the Integrated Management of citrus blackfly. As of 2002, the Federal Rural University of the Amazon (Ufra), Campus Belém-PA, began survey studies on the entomofauna of natural enemies.

Figure 1 - Duration of the citrus blackfly biological cycle

(Photos: V.A. Costa)

In the Pará municipalities of Belém, Santo Antônio do Tauá, Santa Isabel, Ourém, Capitão Poço and Irituia, with greater species richness, 11 predator species known as lacewings (Neuroptera) were recorded: Ceraeochrysa acmon, Ceraeochrysa caligata, Ceraeochrysa cincta, Ceraeochrysa claveri, Cuban Ceraeochrysa, Ceraeochrysa dislepis, Ceraeochrysa dolichosvela e Ceraeochrysa everes, Leucochrysa amazonica, Leucochrysa camposi, and Chrysopodes sp. Ceraeochrysa caligata, C. everes e L. amazonica were the most efficient predators of A. woglumi. Predators were also recorded Ocyptamus gastrostactus (Syrphidae) and the ladybug Delphastus pusillus (Coccinelidae).

3rd instar larva Ceraeochrysa caligata (A) preying on nymphs Aleurocanthus woglumi. 2nd instar larva Ceraeochrysa everes (B) preying on eggs Aleurocanthus woglumi. Santo Antônio do Tauá (PA), 2011 (Photos: Wilson Maia)

postures of Ceraeochrysa caligata in leaves of Citrus sp. Santo Antônio do Tauá (PA), 2010 (Photo: Wilson Maia)

Around 15 thousand eggs/day C. everes are being produced at the Pernambuco Agronomic Institute, IPA, in Recife-PE, and second instar larvae of this predator are released in several municipalities in the state. However, with the occurrence of predation on these eggs by ants, spiders and other arthropods, inundative releases of second instar larvae began. C. everes.

Larva of 3rd (5A) and 2nd (5B) instars

preying on nymphs

in the Sairé field (PE), 2012 (Photos: Wilson Maia)

ladybug adults D. pusillus, in turn, prey on average 14,6 eggs A. woglumi per day, reaching a maximum of 18 eggs. The larvae of D. pusillus, like adults, are also excellent predators of A. woglumi, mainly from their eggs, in addition to being more specific than lacewings. 3rd instar larvae D. pusillus they prey on 22 eggs per day and more than 473 eggs throughout the larval period. The agility of its larvae also allows it to reach and prey on citrus blackfly adults.

adults of Delphastus pusillus preying on eggs and nymphs I, of Aleurocanthus woglumi (Photos: Wilson Maia)

adults of Delphastus pusillus preying on eggs and nymphs I, of Aleurocanthus woglumi (Photos: Wilson Maia)

Larvae of Delphastus pusillus preying on eggs (A) and adults (B) of Aleurocanthus woglumi. 2010 (Photos: Wilson Maia)

Larvae of Delphastus pusillus preying on eggs (A) and adults (B) of Aleurocanthus woglumi. 2010 (Photos: Wilson Maia)

The parasitoids Cales noacki e encarsia sp. were detected parasitizing nymphs of A. woglumi, in Belém, Capitão Poço and Irituia. Cales noacki is more efficient at high citrus blackfly density and citrus parasitism rate. encarsia sp. regardless of pest density.

Found in several Brazilian states, the entomopathogenic fungus Aschersonia aleyrodis It attacks citrus blackfly nymphs and has an orange appearance. In Sao Paulo, A. aleyrodis is a key natural enemy, widely found in citrus orchards with reduced application of fungicides, it has been recorded in every month of the year. Another fungus found on nymphs of A. woglumi in the innermost and lower part of the crown of citrus plants is the reddish-brown fungus Aegerita webberi, which appears to be more sensitive to the application of fungicides.

Click here to read the article in Cultivar Vegetables and Fruits 82.