You're in luck, <name>! I've been working on some of my own experiments while Marvon's been gone, and one of them is a short range bug zapper. With just a few adjustments, it should be great for ridding yourself of those Bloodpetal pests.
I can let you have one of my zapper prototypes, but you'll still need to collect the fuel. You can get the necessary Atal'ai haze that the zapper needs in the temple of Atal'Hakkar. The deep lurkers, murk worms, or oozes are the ones you'll need to get it from.
The quest provides a Bloodpetal Zapper which only works to kill the Bloodpetal Pests in Marshal's Refuge. The Zapper requires one additional follow on step, a Bloodpetal Sprout to be turned into the factioned brother (Larion or Muigin).
This is exhausting, <name>. Those things just won't leave me alone!
So, Marvon wasn't around? Well, show me what you got, anyway.
Patches and hotfixesEdit
Patch 2.4.0 (25-Mar-2008): "Zapper Fuel" is now flagged as a Sunken Temple dungeon quest.