When and how to fallow: first steps towards banana crop yield improvement through optimal and sustainable control of a soilborne pest

Abstract : The main hindrance to banana crop yields is the burrowing nematode Radopholus similis, a microscopic worm that feeds and develops in plant roots. R. similis is an obligatory parasite that fortunately resists badly in the absence of its host. Hence, the deployment of fallows is an efficient way to keep its populations low enough in the soil to have good economic returns on banana bunches. The banana plant is a perennial plant which reproduces itself by budding from its roots, but after a fallow period, a nematode-free sucker needs to be planted to provide for the next cropping season. Fallow is a recommended cropping practice to reduce nematode infestation, but it comes at the cost of nematode-free suckers. Moreover, fallows reduce the time devoted to growing bananas on a given time horizon and may reduce the total yield. A trade-off should then be found between fallow deployment to reduce pest infestation and economic returns. The questions that emerge are when to leave room for the natural reproduction of the banana plant, and when to deploy the fallow? How long to deploy the fallow if applicable? On the basis of mathematical models this paper attempts to answer the questions.