Well, caterpillars eat leaves, many times lots of them.

If only a few, squish handpick and drop into soapy water. If numerous, try Bt (Bacillus thruingiensis) but know that the caterpillars must be less the half-grown for the Bt to work.

I can't see the pic clearly at all. I don't know what all eats sweet broom, but if you only have a few larvae on a big plant, leave them alone because they may be some future butterfly or unique moth.

The Page with the buggy pics has been updated (warning -- link in orig. post won't work no more) ... TreeDaughter managed to take some pics of the buggies that were far better than my pics, so I put a couple of 'em on that page.

Sorry I didn't put no fancy HTML codin' or dancin' gifs, just pics o' bugs and a (very little) bit o' text. But the bug pics is good this time, so I hope some one can tell me what they is. BTW, there ain't "just a few" of these buggy guys ... the plant is practically swarmin' with 'em.

Peace,

- Sequoia

They look like some sort of fritillary caterpillar. There's been a painted lady explosion in California recently. To save your plant, cull only the smallest cats but leave on the big ones which have already finished the bulk of their feeding. Maybe your local extension agent can give you a positive ID.

They are the larva of one of a number of either butterflies or moths. You need to determine yourself whether they are really in need of control or not. How much damage do they really do? How far along in this growht stage are they? Bacillus thuringiensis - Kurstaki is effective but only in the first two, maybe three, weeks of life. If they are causing more damage than you are willing to put up with, then you need to find the least toxic way to control them.
But first positively identify what you have.

I think they're all past the stage where BT will do much good, and I really don't want to resort to anything stronger for this plant. It looks like they've eaten quite a bit, but they ain't gonna kill the plant.

Since it is basically TreeMama's (my DW) "pet bush", she can pick the catepillars if she wants to; I've got my own battle goin' on with the e.vile bermnuda grass.

Peace,

- Sequoia

I have the exact same bug...killing my sweet broom. I will absolutely love it if they are butterflies, however I was thinking that they are some sort of wasp. I too would like to know what they are.

Not sawflies, if that's what you were thinking. They look like one of the Genista caterpillers, in markings.

This is a horrible little creature. I have spent hours everyday picking them off my plant. If they aren't controlled, they will completely destroy it. No, they don't kill the plant, but they completely kill the chance for it to bloom and that is why we bought it. I used a pesticide last year that was organic and it seemed to do ok. But, you still need to continue to pick them off. Unless you have seen what this worm can do to the plant, I wouldn't suggest leaving them alone. The moth does nothing but lay more eggs further reducing the chance of a beautiful plant. The birds don't even eat them - they supposedly taste bad.