Insetos Sugadores (Sternorrhyncha) em Cultivo Orgânico de Tangerina cv. Poncã (Citrus reticulata Blanco): Diversidade, Constância, Freqüência e Flutuação Populacional

O objetivo do trabalho foi estudar a diversidade, constância, frequencia e a flutuacao populacional de insetos sugadores da subordem Sternorrhyncha associados a tangerina cv. Ponca sob o sistema de cultivo orgânico. Os levantamentos foram realizados entre outubro de 2002 e outubro de 2003. Dentre os aleirodideos, Aleurothrixus floccosus Maskell destacou-se dos demais, com media populacional igual a 74,06%. Aleurotrachelus cruzi Cassino obteve media de 52,6%. Entre as cochonilhas destacaram-se Selenaspidus articulatus (Morgan) (23,96%) e Pinnaspis aspidistrae (Signoret) (19,38%). O psilideo Diaphorina citri Kuwayama obteve media de 52,6%, sendo a segunda especie com maior media. Os pulgoes Toxoptera citricida (Kirkaldy) e Toxoptera aurantii (Boyer), somente ocorreram em periodo de brotacao e floracao, com media populacional de 7,6% e 6,25%, respectivamente. Quanto a diversidade das especies o periodo com maior diversidade, ocorreu na 1a quinzena de setembro de 2003 (H’= 0,964), coincidindo com a menor dominância (D= 0,200), e menor diversidade na 1o quinzena de maio de 2003 (H’= 0,657) e maior dominância (D= 0,522). As especies constantes foram: A. floccosus (100%), A. cruzi (96%), Coccus viridis (Green) (100%), P. aspidistrae (100%) e D. citri (100%). As especies mais frequentes foram: A. floccosu s (30,79%) e D. citri (21,87%). Os resultados sugerem que as especies verificadas possuem a dinâmica populacional em parte influenciada pela competicao interespecifica, pois quando ha um aumento populacional dos aleirodideos, ha um decrescimo da populacao das cochonilhas e vice-versa, alem dos fatores ambientais, a predacao e o parasitismo. Sucker Insects (Sternorrhyncha) in Organic Cropping of Tangerine cv. Ponkan (Citrus reticulata Blanco): Diversity, Constancy, Frequency and Populational Fluctuation Abstract. The aim of this work was to study the diversity, constancy, frequency and the population fluctuation of the sucker insects of the suborder Sternorrhyncha associated with the tangerine cv. Ponkan cultivated under the organic. The study was conducted from October 2002 to October 2003. Among the whiteflies, Aleurothrixus floccosus Maskell had a population average equivalent to 74.06%. Aleurotrachelus cruzi Cassino reached 52.6%. Among the scale, Selenapidus articulatus Morgan reached 23.96% and Pinnaspis aspidistrae (Signoret) 19.38%. The Diaphorina citri Kuwayama average was 52.6%, the second bigger average. The aphids Toxoptera citricida (Kirkaldy) and Toxoptera aurantii (Boyer) took place only during the budding and blooming, presenting a population average of 7.6% and 6.25%, respectively. The period in which occurred the largest diversity was the first fifteen days of September 2003 (H’= 0.964), simultaneously to the least dominance (D = 0.200), and in the first fifteen days of May 2003 occurred the least diversity (H’= 0.657) and the largest dominance (D = 0.522). The constant species that were more prominent were: A. floccosus (100%), A. cruzi (96%), Coccus viridis (Green) (100%), P. aspidistrae (100%) and D. citr i (100%). The most frequent species were A. floccosus (30.79%) and D. citri (21.87%). To sum up, the results show that all the species studied have a population dynamics in part influenced by the interspecific competition, as there is a population increasing of whiteflies, there is a population decrease of scale and vice-versa, as well as the environmental and predatory factors and the parasitism.