Presence of Aleurocanthus woglumi in French Guiana and success of biological control
In French Guiana, the presence of Aleurocanthus woglumi (EPPO A1 quarantine pest) has been reported in citrus orchards since July 1995*. As chemical treatments did not give satisfactory results, trials were set up to assess the efficacy of biological control. Encarsia opulenta, Eretmocerus serius and Amitus hesperidum have been identified as useful biological control agents, and according to the experience gained in Jamaica, Barbados and Puerto Rico, it appeared that E. opulenta is the most effective agent in controlling A. woglumi populations. The introduction of E. opulenta into French Guiana was decided and trials were carried out in 1999 and 2000 to assess its efficacy in 2 citrus orchards (near St Laurent-du-Maroni and Cacao). At the beginning the trial, the percentage of attacked leaves was 25-30 % (in the two orchards, respectively). After 2 months, a significant decrease in pest populations was observed. After 12 months, a parasitism rate of 70-90% was reached, and the percentage of attacked leaves was only 7-10 % (below economic threshold). It was concluded that the use of E. opulenta had been successful in controlling populations of A. woglumi in citrus orchards. However, it is noted that in French Guiana, citrus orchards are isolated and separated by large spaces occupied by Amazonian forest, which represents an obstacle to the natural spread of E. opulenta.
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* ; ; ; ;The EPPO Secretariat had previously no data on the occurrence of A. woglumi in French Guiana.
Sources
Janelle, J.; Séguret, J.;; Etienne, J.;; Vaillant, D.;; Didelot, D. (2000) L’aleurode noir des citrus. Succès de la lutte biologique en Guyane française.
Phytoma – La Défense des Végétaux, no. 532, 60-63.