The octoPus: An open-source software for supporting farmers in the control of grapevine downy mildew

• The octoPus is an open-source digital tool to predict grapevine downy mildew infections. • It combines an ensemble of disease models with machine learning and large language models. • The software allows users to run the models and parameterize them for different environments. • The primary aim is allowing farmers and extension services to use it to preserve grapevine health. • The octoPus promotes integrated pest management through an open and collaborative approach. Achieving the European Green Deal objectives necessitates adopting Integrated Pest Management practices as the standard. The limited availability of open-source software for predicting crop fungal diseases hinders European farmers and extension services from tailoring crop protection strategies based on weather conditions favorable for infections. Here, we introduce the octoPus, a free digital tool featuring an ensemble of models predicting grapevine downy mildew outbreaks, enhanced by a machine learning algorithm and a large language model, aimed at providing science-based and easy-to-interpret decision support. The octoPus can be adapted to different scenarios and extended with additional models by third parties. With a focus on open access and code sharing, the octoPus promotes a transparent and informed approach to designing sustainable crop protection strategies.