Tripes (Thysanoptera: Thripidae) em roseira: primeiro relato de scirtothrips dorsalis, distribuição de Frankliniella Occidentalis e seu controle com agentes biológicos

Abstract

Thrips (Thysanoptera: Thripidae) are pests in several crops of economic importance and are distributed throughout the world. The presence of thrips on rose bushes has a significant impact on the quality of flower buds sold. Considering that the brazilian thrips fauna is one of the most diverse on the planet, several species are constantly reported for the first time in Brazil and also in different cultures. Thus, we recorded the first occurrence of Scirtothrips dorsalis in rose bushes, in the south of the state of Minas Gerais, Brazil, and illustrated the injuries caused to the different organs of this plant. Immatures and adults of S. dorsalis were collected from different parts of rose bushes cultivar Avalanche. Furthermore, we evaluated the distribution of Frankliniella occidentalis in cutting rose bushes and determined the best sampling unit to compose a sampling plan for this thrips on this plant. This study elucidated the distribution of immature and adult F. occidentalis in reproductive structures and vegetative parts, and also determined the ideal sampling unit for sampling these organs in cutting rose plants. Finally, the impact of biological agents applied alone or in combination to control F. occidentalis in rose bushes was evaluated. We observed that releases of the predator Orius insidiosus proved to be efficient in reducing the population of F. occidentalis. We found that the predatory mite Stratiolaelaps scimitus, the entomopathogenic fungus Beauveria bassiana, and the combined use of S. scimitus + B. bassiana, compared with the control (non-control) and the farm treatment (control routinely adopted on the farm), did not present significant difference throughout the entire experimental period, not preventing the thrips population increase when comparing the initial and final population density. Our observations and results show that: a) S. dorsalis has the potential to become a pest in commercial rose areas; b) the distribution of F. occidentalis in rose bushes indicates the ideal location for targeting control measures; and c) the biological agents studied can be part of F. occidentalis control strategies in areas cultivated with rose bushes.