Here is the link to the research on soybean oil for aphids on daylilies:
http://botanicaloils.tennessee...
Diatomaceous earth is the remains of ancient diatoms, it's a whitish powder that scratches the pests so they die. Doesn't look all that nice but if you're staying indoors away from the cold that probably doesn't matter
More info:
http://cals.arizona.edu/urbani...
(Edited to add better link)
