Temporal Dynamics of Sporulation of Lecanosticta acicola in Detached Pinus taeda Needles

The timber industry in the southeastern United States relies heavily on Pinus taeda . Over the past decade, impacts from Lecanosticta acicola causing Brown Spot Needle Blight have been increasing on P. taeda . Disease spread is well documented for living needles, with conidia spreading locally and ascospores spreading long distances. Still, little is known about survival of L . acicola in needles once removed from the tree. The objective of this study was to understand temporal persistence and seasonal sporulation patterns of L . acicola after being removed from the tree. Understanding how detached needles contribute to inoculum load is essential for better management practices, as some needles fall to the ground and others get stuck in the canopy, close to living foliage. In this study, infected needles were removed from living trees in November 2023 and March 2024 and the needles were monitored for 1 year after removal. Monitoring ended after 1 year due to annual needle fall, which adds fresh fallen needles. Each week, needles were selected and placed in sporulation chambers for identification. The microbe of interest, L. acicola , was recovered at the 1‐year mark. Other microbes found were Pestalotiopsis sp., Diplodia sp., Hendersonia sp., Coleosporium sp., Lophodermium sp., Alternaria sp., and Trichoderma sp., with all but Coleosporium sp. and Lophodermium sp. recovered at the 1‐year mark. These findings confirmed detached needles can continue to sporulate L. acicola for at least 1 year after removal. Future work should focus on determining L. acicola spread from detached needles, including both needles that get stuck in the canopy and needles that fall to the ground.