I just saw this on a show, but I haven't used it. Hope it helps.
"Geranium bud worm, tobacco bud worm, whatever you call it, it is a pest! These small caterpillars can do real damage to your geraniums, petunias and other flowers and vegetables in your garden. Ferti-lome has a new organic product on the market called ÂBorer, Bagworm, Leaf miner & Tent Caterpillar Spray that will help you control them biologically. If you spray now it will get rid of the pests and it will leave a residual layer to take care of those late arrivals! Tom Combs of GardÂn-Wise Distributing even showed us a new type of hose end sprayer that allows you to screw the product bottle on to the end of the hose. Check out your local independent garden center for this great new Âgreen product."

Jane, it is now 2008. Have you solved your bud worm problem? I also garden without chemicals so the bud worm is a problem for me too. However, I found that they don't attack ivy geraniums so that is all I plant now. Just today I got baskets at W-M with four ivy geraniums in each basket for $10. I will take those out and repot in my pretty hanging baskets and pots. Don't even bother to grow the "standard" geraniums anymore, or Petunias becasue they eat those too.
Tina