No abstract

Resumo. O pulgão Toxoptera citricida (Kyrkaldy) (Sternorrhyncha) é um potencial transmissor do vírus da tristeza cítrica sendo considerada uma praga importante para a cultura. Foi realizado monitoramento quinzenais no período entre outubro de 2002 a outrubro de 2003, com o objetivo de estudar a dinâmica populacional deste afídeo, incluindo predadores e a interação com formigas. Este levantamento foi realizado em cultivo orgânico de tangerina cv. Poncã, Fazendinha Agroecológica, Seropédica, RJ. A análise faunística dos formicídeos atendentes e dos predadores, foi através dos índices de diversidade . Ant-tending was considered medium to H' value (0.6585) and high to D value (0.9012). The equitability was considered medium too (e = 0.69). T. citricida populational dynamic is influenced to foliar shoot following predation and ant-tending. These two end factors are antagonist due to protection offer to ants at BCA.

O objetivo do trabalho foi estudar a diversidade, constância, freqüência e a flutuação populacional de insetos sugadores da subordem Sternorrhyncha associados à tangerina cv. Poncã sob o sistema de cultivo orgânico. Os levantamentos foram realizados entre outubro de 2002 e outubro de 2003. Dentre os aleirodídeos, Aleurothrixus floccosus Maskell destacou-se dos demais, com média populacional igual a 74,06%. Aleurotrachelus cruzi Cassino obteve média de 52,6%. Entre as cochonilhas destacaram-se Selenaspidus articulatus (Morgan) (23,96%) e Pinnaspis aspidistrae (Signoret) (19,38%). O psilídeo Diaphorina citri Kuwayama obteve média de 52,6%, sendo a segunda espécie com maior média. Os pulgões Toxoptera citricida (Kirkaldy) e Toxoptera aurantii (Boyer), somente ocorreram em período de brotação e floração, com média populacional de 7,6% e 6,25%, respectivamente. Quanto à diversidade das espécies o período 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 espécies constantes foram: A. floccosus (100%), A. cruzi (96%), Coccus viridis (Green) (100%), P. aspidistrae (100%) e D. citri (100%). As espécies mais freqüentes foram: A. floccosus (30,79%) e D. citri (21,87%). Os resultados sugerem que as espécies verificadas possuem a dinâmica populacional em parte influenciada pela competição interespecífica, pois quando há um aumento populacional dos aleirodídeos, há um decréscimo da população das cochonilhas e vice-versa, além dos fatores ambientais, a predação 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. citri (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.

This paper deals with a survey and identification of soil ant species (Hymenoptera, Formicidae) occurring in organic coffee (Coffea arabica) crop in order to determine species richness and diversity, as well as the ant species to be used as bioindicators of habitat disturbance in the coffee agroecosystem. Two experiments were set in an organic coffee (Coffea arabica) plantation in Dois Corregos, State of São Paulo, Brazil, one in rainy season (experiment I, February/2008) and other in the dry season (experiment II, July/2008). The ants were collected by using Pitfall trap and Winkler trap and the material was brought to the laboratory were the ant species were identified. There were two coffee areas: sun exposed crop and shadowed crop. One collected 7.101 specimens distributed in 38 species. Few species were constant and frequent ones along the research: Collect I-sun exposed and Collect II-shadowed crop, according to Shanon-Wiener and Simpson indices. The only point to present high dominance was observed in Collect I-sun exposed. One conclude that Linepthema humile is the ant species to be used as bioindicator of habitat disturbance in the organic coffee.