Junk Mail

Is there anything you can do about the junk mail now appearing in the ‘Recent Comments’ section on my Homepage (or should I say dashboard??) for example:

From dark on Summer Wednesday Evenings at Time and Tide # [Pending]
came; buy cheapest etc;
or another:
From century on Samba Magdalena # [Pending]
river; etc;
…..or yet another:
From shoe on Summer Wednesday Evenings at Time and Tide # [Pending]
question; etc;
….. and there’s plenty more where that came from. If this website is to become a useful networking tool as we all hope it will, these timewasters need to be barred from using it