My research focuses on assessing the impact of planting date and the environment on sunflower development, Sclerotinia head rot, and yield. Sunflower is the third major grain crop grown in South Africa and is used to manufacture sunflower oil and oilcake for animal feed. Recently high incidences of Sclerotinia head rot were reported in the northern Free State and North West provinces of South Africa. Climatic conditions and planting dates have been reported to have an impact on the disease, yield, and development of the crop. However, very little information is available on Sclerotinia head rot and how the climate and planting date impact on it. This research will, therefore, endeavour to answer the question of how planting date and environment impact on sunflower development, Sclerotinia head rot and yield. The focus areas will be Gauteng and North West province. One of the objectives is to start developing a model that can be used to predict the impact of planting date on sunflower physiological development, Sclerotinia head rot, and yield. A long term goal is to assess the feasibility of incorporating climate change scenarios into such a model for a long term view of sunflower crop production and disease management under climate change conditions.