Flooding a message from the sink has been widely used in wireless sensor networks (WSNs) for many purposes like synchronization, code dissemination etc. However, relatively little work has been done for flooding in low-duty-cycle WSNs with unreliable links. In the paper, we present an energy-efficient flooding algorithm with minimum latency (EFML) in asynchronous low-duty-cycle WSNs, The key idea is to construct the shortest path tree based on the paths with the minimum delay from the sink to other nodes, then construct a spanning tree with the given delay constraint by locally adjusting the s...