Associação de Beauveria bassiana (Bals.) Vuill. e Piretro [marca registrada] para o controle de Thaumastocoris peregrinus (Carpintero & Dellapé)

Abstract

With the increase of planted forests of eucalyptus in Brazil, the population of insect pests is increasing and causing numerous injuries. Thaumastocoris peregrinus presents fast forward on that culture causing fall of attacked leaves, chlorosis and even tree death. In light of this problem, many attempts to control possible are being carried out, highlighting the biological control with the use of entomopathogenic fungi and the alternate control with the use of plant protection products of natural origin. Based on this, the objective of this study was to evaluate the longevity of adults of T. peregrinus when subjected to the combination of Beauveria bassiana and Piretro [marca registrada]. For this the following treatments were carried out: 1) sterilized distilled water (control); 2) Distilled water containing Tween 80 (0.01%); 3) Piretro [marca registrada]; 4) Commercial B. bassiana, the standardized concentration of 1,0x108 conídios.mL-1 and 5) Piretro [marca registrada] Association + B. bassiana. The leaves of Eucalyptus benthammi were bathed in corresponding solutions and after evaporation of water were cut and fed to the insects and maintained in glass vials sealed with cheesecloth and stored in a climatized chamber (26 ± 2 ° C, 12 hr photoperiod and RH 70 ± 10%). They were performed 20 repetitions per treatment, each vial being a repeat containing an insect. The dead insects were placed in a moist chamber for about ten days for observation and confirmation of mortality with B. bassiana. Treatments 2 (Tween [marca registrada]) and 4 (B. bassiana) does not differ from the control containing sterilized distilled water. Adult T. peregrinus who came into contact with the product Piretro [marca registrada] had their average longevity of 2.6 days or 62 hours. The association fungus B. bassiana + Piretro [marca registrada] decrease the longevity of T. peregrinus compared with the control containing sterilized distilled water, where survival of the insects was 1.5 days (36 hours). When subjected to a humid chamber, treatments 4 (B. bassiana) and 5 (fungus B. bassiana + Piretro [marca registrada]) there was fungus growth on the insect and can prove that this would also act for insect mortality if not Piretro [marca registrada] to take effect. It can be concluded that the fungus association B. bassiana and alternative product Piretro [marca registrada] had positive effects for the control of T. peregrinus.