Role of baculoviruses in insect pest resistance management programs

Use of Baculoviruses (IRAC Mode of Action Group 31) in Brazil has increased significantly in the last 5 years. At least 10 commercial products (single virus or pre-mixtures of two or more viruses) have recently been registered, representing three Baculovirus groups: (1) Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) for control of Fall Armyworm, (2) Chrysodeixis includens nucleopolyhedrovirus (ChinNPV) for control of Soybean Looper, and (3) Helicoverpa armigera nucleopolyhedrovirus (HearNPV) for control of H. armigera, H. zea, and C. virescens. Our laboratory characterized the baseline susceptibility of FAW, SBL, and H. armigera field populations collected in different states of Brazil to these baculovirus-based insecticides. We also evaluated these Baculovirus-based insecticides against well-characterized laboratory resistant strains to understand the potential for cross-resistance to synthetic insecticides and/or Bt proteins expressed in Bt crops cultivated in Brazil. Our results showed low interpopulation variation in the susceptibility of these field populations to the corresponding baculovirus-based insecticides. In addition, no cross-resistance was detected between the baculovirus-based insecticides and Bt proteins or selected synthetic insecticides with different modes of action. The low variation in susceptibility suggests low risk for resistance development. The lack of cross-resistance suggests that these baculoviruses will be effective against host insect pest populations that have developed resistance to insecticides and/ or traits. The combined results from these studies indicate that baculovirus-based insecticides can be valuable tools in Integrated Pest Management (IPM) and Insect Resistance Management (IRM) programs. We will discuss how baculovirus-based insecticides may be incorporated in IRM programs in various agriculture production systems.