Insect repellent dispersed into cellar (10)
I believe the answer is:
citronella
'insect repellent' is the definition.
(oil used as an insect repellent)
'dispersed into cellar' is the wordplay.
'dispersed' is an anagram indicator.
'into'+'cellar'='intocellar'
'intocellar' anagrammed gives 'CITRONELLA'.
(Other definitions for citronella that I've seen before include "Insect-repelling oil" , "South Asian grass" .)