Try the clone stamp tool.
Another approach is to make a selection of an adjacent ("good") area with the lasso tool, place the selection on its own layer (CTRL+J), then use the move tool to slide it over the unwanted object.
The recompose tool (ALT+CTRL+R) may work also.
You might want to post your picture in another message so that we can offer suggestions. Click the camera icon to upload it into the message.