There is a non-toxic thing to use that will keep the tobacco budworm from totally munching away, it is called bacillus thuringiensis or BT for short. Nursery or yard store will carry it. Spray once a week

Likely your CAT is a Tomato or Tobacco Hornworm...you really don't need a chemical at all to deal with this..they are big enought to see and to pick off as you find them.

Vera

You just say "something". Are you sure it's even a caterpiller? Slugs eat petunias. Lots of bugs eat petunias. The key to knowing the right remedy is knowing the right problem.

If it IS a hornworm it would be pretty hard to miss! If you don't see them..you ain't got'em :)

Vera

Here is a link that might be useful: {{gwi:21149}}

And you can have slugs, even if you don't see them. Go out with a flashlight at night and peek.

Sounds like slugs to me too......it's their favourite food, the petunia. The smaller the slug, the more damage. There are lots of slug killers out there. I used salt one year(ringed around the petunia bed), it worked great.

here's another possibility ......
i have one one spot of petunias in a hanging basket that a species of birds (yellow vented bulbul- pycnonotus xanthopygos)LOVES to munch away at- buds, leaves, flowers- you name it. on the other hand, the ones in the garden are unappetizing to them. :)
dory

The blooms on my petunias were being munched away and my sister told me it's probably cabbage loopers. She uses BT to get rid of the problem.

I also have nasty green caterpillars eating my petunias and now my geraniums. Sevin does not work. Picking them off each day takes hours. They blend in with the color of the foliage and multiply rapidly. HELP!

The green tobacco budworm is THE primary pest of petunias in some areas! Difficult to control....but proper identification is important.

Here is a link that might be useful: {{gwi:21151}}

I'm finished with petunias for a few years. Whether it was slugs or caterpillars, something had a great petunia feast.The first year wave petunias were a beautiful show. This year I kept replanting only to have the same thing happen. Petunias eaten!!! I tried every remedy for slugs so maybe it was caterpillars ( though I never saw them ). Verbena had lovely blooms and did well. Why torture myself with petunias?

I too have had something eating my petunias this year, I did find a web site that offered help, www.garden-services.com/petunia. Here's what they had to say;

One of the most common pests of petunias is the budworm caterpillar. These small green worms appear in late June and July. You won't often see the worm itself. Instead, you'll see the droppings, which often are described as small black seeds. The worms feed on the flower buds, making small holes in the buds and the leaves.
These caterpillars are difficult to control but Dipel, Thuricide, Talstar and Scimitar are reasonably effective insecticides. Sevin and Diazinon aren't effective, because budworms have become resistant to them. If left unchecked, the presence of the caterpillars will cause petunias to stop blooming.
Hope this helps!

I have seen these little pests on my petunias. According to the pics posted here it is definitely the Tobacco budworm. These pests can be seen munching away early in the morning and just before sunset. Heat of the day they disappear. There are many gardens in my neighborhood that have petunias planted but mine seem to be the only ones affected. Very strange. Anyway, I'm going to try this BT next year as I truly love petunias. Thanks for all your info.

I too, had the budworm on my petunias only in 1 bed. 2 years in a row, so I did not put them in this bed this year. I opted for knock out roses instead. The other areas are,were not affected. I did some research(Penn State) and identified it as the budworm. (first name, anything you want) It is a relative of the same that affects corn, and has become resistant to most killers as so many pesticides were used in growing corn. It said the most affective "cure" was to pick off the buds that had the holes, and eventually I guess you control them. I haven't had them at all this year, so evidently they live in the ground where I had this particular bed of petunias and they don't like this years menu, but I'm not sure. Faye in MD