If you have only one adb-capable device, use this command:
phonegap run android --device
If you have more than one you will need to specify the device ID this way:
phonegap run android --device=<device-id>
Example:
phonegap run android --device=SH25PW103163
phonegap run android --target=SH25PW103163
If you want to know the code of a device execute this in the console (shell, terminal):
adb devices