Hi Mike,
The only way of ridding yourself of these lovely little thugs is to let them come up, flower, then after that spray the foliage once a week with a glyphosate-based weedkiller like roundup or weedol. This is the time of year when the bulb is trying to store any leftover goodness from its leaves, so will hopefully take down some poison too - doing it before flowering is pointless, as everything is rising from the bulb then, not going back down. It worked in my dad's garden, which was FULL of them, like grass. It took weekly applications for two seasons though...
