This paper proposes two joint routing and scheduling algorithms which minimize the data delivery latency while enhancing the energy efficiency in wireless sensor networks (WSNs). In our algorithms, we first model the network as a directed graph Ginit orientating to the sink node on the basis of the location and lossy behavior of the wireless links. Next, we introduce two directed graphs Gres and Ghip taking into consideration the energy efficiency and latency, respectively. The scheduling algorithm is developed on the two graphs by solving an integer linear program (ILP) that minimizes energy consumption and mean latency in the network. Owing to the blacklist of links in the two graphs Gres, Ghop with respect to Ginit, the computation complexity of ILP is decreased considerably. Simulation results show that our proposed algorithms are highly effective in improving network performance.