Black Aphids

Hi,
I have (what I think are) black aphids destroying my nastursiums. What can I do to stop them? I really prefer not to use chemical pesticides but went and looked a few up out of curiousity and all of them said specifically that they could not be used on nastursiums. I've tried spraying them off with water, which I found requires so much force it was destroying the plants anyway. I've also tried selectively cutting off the most infested portions, but at the rate these things are going I might as well just take them all out! They've now spread to my poppies, and I'm worried at this point that they're going to take over my whole garden. There's only about a month or so left for the nastursiums, but I'd like to learn a bit more so I can 'nip the problem in the bud' ;) next year! Any advice would be greatly appreciated!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I use a couple teaspoons of dish detergent and vegetable oil in a quart of water and spray them every few days for two weeks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Vox Humana wrote:

Thanks Vox Humana! I'll give it a try and let you know how it works out.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.