Integrative Techniques Confirms the Presence of Bemisia tabaci Parasitoids: Encarsia formosa, Encarsia porteri and Eretmocerus mundus (Hymenoptera: Aphelinidae) on Soybean and Tomatoes in South Brazil.

Parasitoid wasps from the Aphelinidae family (Hymenoptera) are important control agents of Bemisia tabaci (Gennadius, 1889) cryptic species, both through reproduction and feeding processes. Identifying native parasitoid species within agricultural systems affected by Bemisia whitefly species is the first step to developing guidelines for the creation and release of biological control agents aiming at this highly damaging pest species complex. Taxonomic and phylogenetic analyses based on morphological and molecular characters, respectively, confirmed the occurrence of Encarsia formosa (Gahan, 1924) in greenhouse tomatoes from Santa Maria, Encarsia porteri (Mercet, 1928) in open-field soybean from Santa Maria, and Eretmocerus mundus Mercet, 1931 in greenhouse tomatoes from São José do Hortêncio, all within Rio Grande do Sul state (South Brazil). This is the first report of En. formosa, En. porteri and Er. mundus parasitising B. tabaci in South Brazil, and the first En. porteri partial mtCOI gene sequence being reported and characterised. The high temperature inside the tomato greenhouses can be a possible cause for the predominance of Er. mundus in São José do Hortêncio, and sex ratios in the surveyed populations point to female and male prevalence within Encarsia and Eretmocerus genera, respectively. The combined use of taxonomic and molecular characterisation highlights the importance of combining both morphological and molecular approaches in the assessment of previously unidentified whitefly parasitoids.

Arthropod Invasions Versus Soybean Production in Brazil: A Review.

Soybean production in Brazil has been markedly affected by invasions of non-native arthropod species that feed on the crop, severely impacting biodiversity, food security, health, and economic development. Data on soybean production losses and increase in insecticide usage over the last two decades have not been explored in association with past invasion events, and the dynamics underlying the recent blitz of invasive species into Brazil remain largely unclear. We provide a review of arthropod invasions in the Brazilian soybean agroecosystem since 1990, indicating that the introductions of Bemisia tabaci (Gennadius) MEAM1 (Hemiptera: Aleyrodidae), Tetranychus urticae (Koch) (Acari: Tetranychidae), and Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) are likely correlated with periods of increase in insecticide usage for soybean production. Using these three cases as examples, we review factors that could lead to increased likelihood of future invasions by particular pests, outlining four possible criteria to evaluate potential invasiveness of non-native arthropods: likelihood of entry, likelihood of establishment, biological features of the species, and availability of control measures. Spodoptera litura (F.) (Lepidoptera: Noctuidae) and Aphis glycines (Matsumura) (Hemiptera: Sternorrhynca) are examples of highly damaging soybean pests, related to one or more of these factors, that could be introduced into Brazil over the next years and which could lead to problematic scenarios. Melanagromyza sojae (Zehnter) (Diptera: Agromyzidae) also meets these criteria and has successfully invaded and colonized Brazilian soybean fields in recent years. Our review identifies current issues within soybean pest management in Brazil and highlights the need to adopt management measures to offset future costs and minimize lost revenue.