Possible Clues:

• When it comes to 6.50 one is just a little grubby
• We get such bad grub
• Insect pest that damages crops
• Small mostly disgusting beetle
• The little six-fifty is so grubby (6)
• We get nasty beetle
• Beetle with an elongated snout
• Small, nasty tailless beetle
• What's small and mostly harmful?
• We live with small beetle that feeds on grain and tree-bark