Bacillus thuringiensis resistance of diamondback moth in a broccoli crop

The diamondback moth is one of the world's most destructive pests. Targeting plants such as broccoli and cabbage, they have few natural predators, reproduce effectively, and have been known to establish pesticide resistance over time. In this paper we investigate management of diamondback moth via a bacterial pesticide at a harvesting company. Recognizing evidence of pesticide resistance in the observed data, we quantify this phenomenon mathematically within an age-structured ordinary differential equation model. Significant improvement in the predicted larval population is seen using our model in comparison to an existing model of the same outbreak, in particular in fitting larval growth via incorporation of pesticide resistance. Model predictions of egg and pupal populations are also compared to observed data to gain insight into model accuracy across the life cycle of the diamondback moth.