RESUMO
Phytoseiid mites have been frequently found in association with the lychee erinose mite, Aceria litchii, on lychee plants in Brazil, suggesting that they are promising candidates as biological control agents against this pest. Here, we investigated whether phytoseiids would suppress A. litchii infestation, i.e. formation of erinea, on lychee plants under field conditions. Four groups of A. litchii-infested plants were randomly distributed in the field, with each group receiving either Phytoseius intermedius, Amblyseius herbicolus, A. herbicolus supplemented with cattail pollen or no predator. During a three-month period, the released predators, along with others present in the surrounding environment, were allowed to freely walk among all plants. In each plant, we evaluated the occurrence of phytoseiid species, their abundance, and the dynamics of erinea formation. A total of 2,097 mites, including 13 other phytoseiid species were identified. The most abundant species were Iphiseiodes zuluagai and Euseius ho, rather than the two predator species that were released. A. herbicolus and P. intermedius failed to establish populations in the majority of the plants, regardless of the presence of pollen, suggesting their ineffectiveness in controlling A. litchii infestations. While there was a significant difference in the proportion of erinea among the four treatments, this contrast was not associated with the presence of phytoseiids, suggesting that other factors might have hindered erinea formation on lychee plants. The reasons behind this outcome are further explored and discussed.
Assuntos
Ácaros , Controle Biológico de Vetores , Animais , Ácaros/fisiologia , Brasil , Litchi , Comportamento PredatórioRESUMO
Lychee fruit production (Litchi chinensis) has been threatened in many regions of the world where the presence has been reported of the litchii erinose mite, Aceria litchii (Keifer). This study aims to identify the arthropod community associated with A. litchii on lychee plants in Minas Gerais, Brazil, and to seek for potential natural enemies associated with this mite pest in this region. We sampled lychee leaves infested with A. litchii in commercial and non-commercial lychee orchards during seven consecutive months, covering the dry and wet seasons of the year. Arthropods found in association with A. litchii on lychee leaves were collected and identified. The results indicate that a great diversity and abundance of mites and hexapods are associated with A. litchii. A total of 985 and 1872 specimens of mites were identified in commercial and non-commercial areas, respectively, belonging to the families Cheyletidae, Cunaxidae, Eupodidae, Iolinidae, Stigmaeidae, Phytoseiidae, Tarsonemidae, Tenuipalpidae, Tetranychidae, Tryophtydeidae, Tuckerellidae, Tydeidae, Winterschmidtiidae and Xenocaligonellidae and the suborder Oribatida. Among them, Phytoseiidae was the most abundant and diverse family with a total of 11 species identified, in which Phytoseius intermedius was the most abundant predatory mite species collected. Minor specimens of hexapods were also been, belonging to the orders Collembola, Blattodea, Coleoptera, Diptera, Hemiptera, Hymenoptera, Psocoptera and Thysanoptera. The presence of a high community of predatory mites in association with A. litchii deserves attention and our results indicate that studies to test the potential of these species and the adoption of management practices that enhance this ecological service must be carried out to achieve satisfactory control of the lychee erinose mite in lychee plants.
Assuntos
Artrópodes , Litchi , Ácaros , Animais , Árvores , FrutasRESUMO
Composting is a process recommended as a way to recycle the organic part of the solid waste in which several micro and macroorganisms act as decomposers of the organic matter, in a process that takes around 120 days and faces roughly three different phases. Because we do not know the community of arthropods associated with the compost produced in one of the biggest landfills placed in Brazil, here we collected and identified the community of arthropods present in each phase of the organic compost. Our hypothesis is that the abundance and diversity of arthropods are different within each phase of the compost and we hope to find particular groups of arthropods that can be used as indicator of specific phases. In total, we identified the taxa of 1204 arthropods (insects, arachnidan and diplopods). We found that diversity and abundancy of arthropods were indeed different for each maturation phase of the compost, but we did not find families that are good indicators of each phase. In addition, to be certain about the safety of the compost produced, we investigated the presence of microorganisms in the final product and we found considerable levels of Escherichia coli and Enterococcus faecalis in some samples. Finally, we argue that the presence of these macro and microorganisms during the process may be beneficial or harmful. Since their presence decreased greatly by the end of the process, we acknowledge that composting works efficiently as a way to recycle the organic part of the waste generated in Brazil.