Aphid Control - What works and doesn't

[deluxestogie]

I would not suggest using soap on tobacco. Soap (a salt of a fatty acid) tends to leave a film--think soap scum on the shower door. Detergent is much more soluble, and more likely to rinse away. Dawn is a detergent, as are nearly all dish liquids.

I believe detergent kills insects in two ways. It helps to remove the waterproofing layer on the insect's skin (chitin), causing dehydration. As a surfactant, it likely also penetrates the breathing spiracles along the sides of the insects, and spreads over the internal breathing surface. (Water can't do that because its surface tension is too high to make it through the tiny opening of the spiracles. Like the pores in Gore-tex, spiracles allow water vapor and air to pass, but not liquid water.) Soap likely works to kill insects by the first method. Note that we don't wash our hands with detergent because it is so much more effective at dispersing lipids that it rapidly leads to dry, cracked hands.

Although I do not rinse the leaves that were sprayed with detergent, I have never noticed an off taste. I would not be so confident if I were using soap.

Bob

 

[Jitterbugdude]

I used to use Safers Insecticidal soap but over the years switched to Ivory soap and Dawn detergent. Evidently there appears to be no difference between detergents and soaps when it comes to killing insects. Each seems to carry a similar risk for plant injury. I'll go back to using a detergent next year. I have never noticed any residue/taste from using either. Then again I don't spray the day I harvest. Interesting article follows...

http://www.ext.colostate.edu/pubs/insect/05547.html

 

[Knucklehead]

Bob, if you don't rinse your leaves, what happens to all the dead aphids? Do they just fall off during processing the same way that dirt does? My leaves are covered in them.

 

[LeftyRighty]

Bob, if you don't rinse your leaves, what happens to all the dead aphids? Do they just fall off during processing the same way that dirt does? My leaves are covered in them.

If they don't fall off, or get brushed off after curing, just smoke 'em - they taste fine.

 

[deluxestogie]

...what happens to all the dead aphids?

Where have all the aphids gone, long time passing?
Where have all the aphids gone, long time ago?
Where have all the aphids gone? Gone to floor dust every one.
When will they ever learn? When will they ever learn?
[Pete Seeger, with liberties]

 

[leverhead]

Where have all the aphids gone, long time passing?
Where have all the aphids gone, long time ago?
Where have all the aphids gone? Gone to floor dust every one.
When will they ever learn? When will they ever learn?
[Pete Seeger, with liberties]

I need to start smoking cigars!

To further cloud the issue. All soaps are detergents, but not all detergents are soaps.