Efeito de produtos fitossanitários alternativos sobre Thaumastocoris peregrinus (Carpintero & Dellapé) (Hemiptera: Thaumastocoridae)

Abstract

Eucalyptus has more than 730 species and only in Brazil, occupying more than 6,664,812 hectares of planted area. Due to this fact and the intense monoculture, eucalyptus has an increasingly common insect pest, the eucalyptus bronze bug Thaumastocoris peregrinus. This insect has caused loss of photosynthetic area of the plants, leaves falling from trees, and even death of this culture. Because of this various methods of control, among these, the alternative control with the use of phytossanitary products. Thus, the aim of this study was to evaluate the insecticidal effect of alternative phytossanitary products on T. peregrinus. The experiments to be performed were the Confinement Test, which analyzes the insecticide effect of five phytossanitary alternative products (Azamax [marca registrada], Nim Base [marca registrada], Fortneem [marca registrada], Orobor N1 [marca registrada] and Piretro [marca registrada]) on insects of T. peregrinus in 3rd instar and adult. These products were applied in the concentrations specified by the manufacturer in the test. Eucalyptus camaldulensis leaves were collected and immersed in the solutions of alternative pesticides. To compose the witness, the leaves were immersed in sterile distilled water. After drying, the leaves were cut into 2.4 cm circles subsequently arranged inside glass tubes. In each tube was allocated an adult insect of T. peregrinus. The experiment was conducted in climatic chambers BOD (26 ± 2 ° C, RH 60 ± 10%, photophase of 12 h) and mortality was evaluated every twelve hours until 144 hours. Then, the product that submit have greater potential insecticide in Confinement Test, shall be submitted to the Medial Lethal Concentration Test at concentrations of 0,5%, 1%, 1,5% and 2%. It was used the same method as previously used. All alternative pesticides reduced the longevity of T. peregrinus differing from the control (4.6 days). The Piretro [marca registrada] product caused a reduction in the longevity of T. peregrinus who survived on average 0.5 days, followed by product Base Nim [marca registrada] (1.7 days), Orobor [marca registrada] (1.8 days), Azamax [marca registrada] (2.1 days ) and Fortneem [marca registrada] (2.3 days). In Lethal Concentration Average Test performed with Piretro [marca registrada] all concentrations tested reduced longevity of T. peregrinus, differing from the control (48 hours), whereas the concentration of 1,5% reduced longevity to 0.2 days (4.8 hours). The alternative product Piretro [marca registrada] stood out in reducing the longevity of T. peregrinus requiring additional tests, but it shows the potential to be used for controlling this insect.