Production of Insecticidal Baculoviruses in Insect Cell Cultures: Potential and Limitations

The potential of baculoviruses to be employed as insecticides is known since more than 75 years ago (Benz, 1986). To date, over 30 different baculoviruses are used to control several insect plagues in agriculture, horticulture and forestry (Moscardi, 1999). The use of baculovirus as insecticides is based on a set of useful properties, such as pathogenicity, specificity, narrow host range, environmental persistence, ability to act synergistically with other natural enemies of the pest and ability to induce artificial epizootics. Despite these advantages, very few baculoviruses have become widely used as insecticides, standing out as some successful examples the use of the Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) to control the velvetbean caterpillar in soybean crops in Latin America, Cidia pommonella granulovirus (CpGV) to fight the codling moth attacks in fruit orchards, and Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) to control the armyworm in vegetable crops under cover in Europe (Moscardi, 1999). The causes of the limited acceptance of baculoviruses as insecticides are diverse, including slow speed of action, problems to register and market these biological insecticides and difficulties to produce them at an appropriate scale. The technologies currently used to produce insecticidal baculoviruses are based on the infection of susceptible insect larvae (Black et al., 1997). However, the implementation of processes to produce baculovirus in insect larvae is hampered by several limitations: high labour requirements, lack of expertise in standardization and validation of such processes, difficulties in scaling production to levels consistent with the profitability of the process and difficulties to properly control both the process production and product quality. While several improvements in production systems in insect larvae have been described in the last years which could help overcome some of the problems described above (van Beek & Davis, 2007), it has been also proposed that the adoption of an alternative technology based on the viral propagation in insect cell cultures could enable the development of well standardized, controlled and scalable production processes for insecticidal baculoviruses (Szewczyk et al., 2006).