Ocorrência e controle de Sogatella furcifera em arroz no Brasil

Abstract

The study aimed to confirm the presence of S. furcifera in rice fields in Brazil and to evaluate the efficiency of insecticides available to control this pest. The dissertation It is divided into two chapters. Chapter 1 is the first record of S. furcifera in Brazil. In the study, specimens of the white-backed leafhopper were collected from crops in four Brazilian states, Roraima, Rondônia, São Paulo and Santa Catarina, and later submitted to molecular techniques of extraction, purification, amplification and DNA sequencing. The comparison of the COI region of the mitochondrial DNA, of the collected samples, with the sequence of S. furcifera deposited in the Gene Bank, confirmed the occurrence of the species in the samples of the four states. Thia is the first record of S. furcifera in Brazil, indicating to important risks, given the relevance and distribuition of this invasive pest. Chapter 2 consists of the evaluation of the effectiveness of insecticides for the management of S. furcifera, divided into two experiments, applied in different moments of infestation. The beginning of applications in experiment 1 occurred with a population density of 30 adult leafhoppers and 11 nymphs per 10 sweeps (low population) and in experiment 2, the first spray occurred with a population density of 63 adult leafhoppers and 4 nymphs per 10 sweeps (high population). The insecticides Perito® (acefato na dose de 1164 g i.a ha-¹), Actara® (tiametoxam na dose de 75 g i.a. ha-¹), Zeus® (λ-cialotrina + dinotefuran nas doses de 28,8 + 50,4 g i.a. ha-¹) e Klorpan® (clorpirifós na dose de 720 g i.a ha-¹) are efficient to control S. furcifera with one spray when started at low pest population levels, and with a second spray, when sprayed with higher population levels. The insecticides Engeo Pleno S® (λ-cialotrina + thiamethoxam at rate of 31.8 + 42.3 g a.i. ha-¹), Zeus® (λ-cyhalothrin + dinotefuran at rate of 28.8 + 50.4 g a.i. ha-¹) and Expedition® (λ-cialotrina + sulfoxaflor at rate of 45 + 30 g i.a. ha-¹) are efficient for the control of S. furcifera with two sprays, when started at high pest population levels. The general average of insecticides was superior in the population of nymphs compared to the efficiency in the adult population of S. furcifera. Insecticides are efficient and are important for the management of S. furcifera.