Mites Associated with Soybean Crop in Rio Grande do Sul State, BrazilABSTRACT -During the last growing seasons, high infestations of phytophagous mites were observed in the State of Rio Grande do Sul, Brazil, becoming necessary to apply pesticides for their control. The objective of this study was to identify phytophagous and predatory mite species associated with soybean Mononychellus planki Polyphagotarsonemus latus Tetranychus desertorum Tetranychus gigas Phytoseiulus fragariaeTyphlodromalus aripo De Leon) were found. T. desertorum Phytoseiulus fragariae and T. aripo biological control agents in soybean crop was discussed. Among the hypotheses to explain the increasing the dry spells observed in the last few years in the growing season, changes in soybean cropping system that led to increased use of pesticides and utilization of new soybean cultivars with morphological or biochemicals characteristics that favour the development of these mite populations.KEY WORDS: Glycine max L., Tetranychoidea, Tarsonemidae, Phytoseiidae diversos municípios do Rio Grande do Sul, demandando a utilização de pesticidas para seu controle. à soja em dez municípios daquele estado, nas safras de 2002/03 e 2003/04, em cinco cultivares de Mononychellus planki Polyphagotarsonemus latus Tetranychus desertorum Tetranychus gigasPhytoseiulus fragariae & Schicha e Typhlodromalus aripo De Leon). Tetranychus desertorum foi registrada pela primeira vez, associada à soja, no país. P. fragariae e T. aripo foram registradas pela primeira vez em soja. O a expansão progressiva da área cultivada, os veranicos observados nos últimos anos durante a estação desenvolvimento de populações desses ácaros. PALAVRAS-CHAVE:Glycine max L., Tetranychoidea, Tarsonemidae, Phytoseiidae A soja, Glycine max mais importante no Brasil, ocupando mais de 20 milhões de ha, sendo cultivada em mais de 20 estados de todas as regiões e o maior exportador mundial de grãos de soja. A produção, plantas daninhas e ataque de pragas e doenças. Os insetos têm 2005). Entretanto, recentemente, a ocorrência de ácaros tem ganhado importância, tanto pelos danos à cultura quanto pela necessidade de uso do controle químico.

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ABSTRACT. This study aimed to evaluate the fluctuation of S. frugiperda eggs and natural parasitism by Trichogramma and identify and quantify parasitoid species in maize fields in the state of Rio Grande do Sul, Brazil. Surveys were carried out in two growing seasons: in 2006/2007 we assessed one growing season (late sowing) in Santa Maria, and in 2007/2008 we assessed two growing seasons (early and late sowing) in Santa Bárbara do Sul. Daily air temperature and rainfall were recorded at both locations. In each evaluation, entire plants were examined for the presence or absence of S. frugiperda egg masses, which were analyzed for larvae hatching or parasitoid emergence. The number of S. frugiperda eggs is higher between 8 and 30 days after plant emergence, decreasing in the later stages of maize growth; the occurrence of parasitoids begins about two days after pest egg occurrence; S. frugiperda egg parasitism is low; and eggs are parasitized by Trichogramma pretiosum and Trichogramma atopovirilia, with marked predominance of the first and possible occurrence of both parasitoid species in the same egg mass.

Euplectrus furnius parasitando Spodoptera frugiperda em milho no Brasil ISSN 0103-8478Ciência Rural, Santa Maria, v.43, n.11, p.1958-1960, nov, 2013