The use of baculovirus Spodoptera SfMNPV alone and combined with herbicides and adjuvant to control Spodoptera frugiperda (Smith, 1797) (Lepidoptera: Noctuidae)

Abstract

Four independent experiments were carried out to evaluate the use of Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) alone and mixed in different combinations with herbicides (atrazine and tembotrione) and adjuvant (soybean oil) to control Spodoptera frugiperda in maize. Experiments evaluated S. frugiperda mortality (%) under controlled conditions (26 ± 2 °C, relative humidity of 70 % ± 10 %, and 14:10 h L:D photoperiod) after feeding using a treated artificial diet (experiment 1) and maize leaves (experiment 2), both immediately and four hours after spraying the studied treatments (experiment 3). An additional experiment evaluated plant damage caused by S. frugiperda in the field (visual observation) on various days after spraying the tested treatments (experiment 4). The addition of the herbicide atrazine did not reduce the efficiency of SfMNPV in S. frugiperda control in any of the experiments. Thus, SfMNPV could be used in a tank mix with this herbicide, which would be economically attractive to farmers, facilitating SfMNPV adoption in the field. In contrast to atrazine, the herbicide tembotrione and the adjuvant (soybean oil) had an antagonistic interaction with SfMNPV, but only when sprayed four hours after preparation. Thus, the combination of SfMNPV with tembotrione and soybean oil can also be used by farmers if sprayed immediately after mixing with the baculovirus.