### Clue: Treats with element of additional raise Ben's after (8)
### Answer: SULPHURS 
 ### Explanation: Definition: Treats with element
 **Reversal of**(raise, in a down clue) PLUS(additional;extra) + HUR(Ben, in Lew Wallace's novel) 'S.
Answer: Treats with the element sulphur, which is used as an insecticide.