PPOX and infection: However, apart from the oxidative stress response in the defensive reaction of insects to B. bassiana, the detoxifying enzymes and polyphenol oxidase (PPO) in their bodies also resist the infection of B. bassiana in different ways, for example, the carboxylesterase (CarE) in insects can participate in the detoxification of exogenous substances by hydrolyzing the carboxylester bond [14].