Tripes (Thysanoptera: Thripidae): identificação de espécies e vírus associado à cultura da melancia

Abstract

The Watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] is originally from Central Africa, and cultivated worldwide. In 2012, the world production of this fruit was 105.372.341 million tons, while Brazil produced 2.079.547 million tons. The watermelon cropping is of paramount economic importance to the state of Tocantins, with revenues of 98.5 million, in 2013. Watermelon is susceptible to the action of microorganisms, and viral diseases presents most relevance. The Tospovirus genus, transmitted exclusively by thrips vectors in diverse crops, have caused losses of billions of dollars in cost control. Thrips are found in all regions of Brazil, with high infestations in watermelon crops, and may cause direct and/or indirect damages. In this work, it was collected thrips specimens from watermelon producers of municipalities in the state of Tocantins: Gurupi, Formoso do Araguaia, Lagoa da Confusão and Porto Nacional. The thrips identification of morphological characters was performed using appropriate taxonomic key with changes to species identification. In part of the collected insects, the total RNA extraction was performed. The extracted was subsequently sequenced with next-generation sequencing technology (NGS). Three species of thrips were identified in the four producing municipalities, F. schultzei, F. tritici, and F. insularis, with predominance of F. schultzei. Among the identified species, only F. schultzei is considered a vector of Tospovirus. In thrips samples it was identified the virus Groundnut ringspot virus (GRSV), which is efficiently transmitted by F. schultzei. Among the species of thrips identified, F. tritici and F. insularis, are registered for the first time in watermelon commercial crops in Brazil. F. schultzei is the only one with reports of direct and indirect damage to watermelon plants and may be considered as a potential plague due the high population level found and difficulties in controlling it.