Planting date impacts disease progression and yield of chickpea ( <i>Cicer arietinum</i> L.) grown in the Northern Great Plains

Production of chickpea (Cicer arietinum L.) has expanded in Montana and North Dakota due to its ability to thrive in semiarid conditions as well as its use in crop rotations to disrupt disease cycles in small grains and other pulse crops. However, the high degree of susceptibility of this crop to soil-borne and foliar disease is a major production constraint. Avoiding cool soil temperatures by delaying planting is a strategy to reduce potential yield loss to Pythium seed rot and damping off in chickpea, but effects on Ascochyta foliar blight (AB) are unknown. Within the United States, chickpea planting dates are dictated by crop insurance restrictions which have not been updated in many years. A study was conducted at six locations in Montana and North Dakota from 2021 through 2023 to determine how delaying planting affected chickpea seed yield and quality, including test weight and protein. Additionally, we assessed seedling emergence, AB foliar disease, seed size, and seed infection to determine if delayed planting improved disease management. For all site-years in which AB was present, delayed planting by 2-3 weeks resulted in less disease but negatively impacted yield (P < 0.05). Effects of fungicide applications and variety were also examined and did have effects on other metrics but did not significantly impact yield or disease. The results of this research support the current practice of early planting to avoid late-season drought in Montana, North Dakota, and similar semi-arid environments where alternative strategies are available to manage disease.