Usually a population explosion in one species is followed by a population explosion in another species a bit higher up the food chain. Long term you could try and encourage predator species like birds and parasitic wasps. You'd have to figure out what the critter is first and what eats it.

But, that doesn't help you now does it? First thing I would try is to put some soap in a hose end sprayer and see if you can knock 'em off the stuff you value most. Then I would call the equivalent of your local county extension office and see if they know what they are and whether they can suggest a remedy. You can usually send a sample for ID.

Good luck!

I have had good luck using insecticidal soap mixed with neem oil. I, too, refuse to use pesticides, but this concoction works for almost everything here. As an added benefit, the deer and other critters don't seem to like the "garlicky-sulphur" smell (or taste?). We mix up a batch in a small hand pump sprayer and spray away.

Hope this helps!

Thank you for your suggestions. Do either of you (or anyone) know what those little green worms are that love to eat columbine to the ground? That is what is on everything. My neighbor's roses are chewed all up in half-moon circles, their lilac and their sand cherries, all bombarded with these little green worms. Forget Columbines this year, they will eat one to the ground in one night. I've lost 3 completely and they aren't growing back for the second time this year and a 4th one is about to go. Whatever those green things are they are driving me nuts.

Barb

It is hard to diagnose your problem without seeing the worm - or is it a caterpillar?

Green worms on your columbine could be an inch worm or canker worm. If the caterpillar loops up in the center or arches as it moves along, it could be a looper or cabbage worm.

It's sawfly larvae. I bought malathyon but it, nor any other pesticides I looked at mention sawfly or sawfly larvae on the label. It seems like a fairly broad spectrum pesticide though, so it should work. I'm not into using pesticides but at this point we are losing hundreds of dollars worth of plants from one day to the next and I'm desperate.

Barb

Sawfly larvae are fairly easily controlled with insecticidal soap applications. Spray in the evening when you are likely to get the most benefit from the solution.

Columbine sawfly larvae are a very common pest of this plant. Best to keep your eyes out VERY early for the insects, before they grow big enough to do much damage.

Insecticidal soap will do less injury to whatever balance of beneficials you may have in the area, than the malathion.

Here is a link that might be useful:

Malathion is bad for you and bad for the enviornment. We have been fighting here on Long Island to get them to stop arial spraying of mosquitos w/ it. It is believed it may have decimated the lobster population in LI Sound by causing problems w/ their nervous systems. After many expensive lawsuits they have mostly stopped using it. I would try soap or neem oil or something as specific to the pest as possible first. Broad spectrum insecticides often create many new problems long term that one might not even think of.

Something with BT, bacillus thoringiensis, a naturally occuring bacteria, is typically recommended for caterpillars. For what ever reason it specifically attacks them (which is why its so effective for mosq. larvae), and leaves other things alone. Its perfectly safe around kids, pets, fish, other plants, etc. Its widely available in various forms. Another thing you could try is diatomaceous earth. You can sprinkle the powder on your plants and ... in theory anyway...the sharp edges of the tiny particles will pierce the skin of the worms thus repelling and/or killing them. Good luck!

Bt will not work on sawflies. Bt only works on caterpillars and sawflies are not caterpillars. Caterpillars are larvae of butterflies and moths - Lepidoptera. Sawflies are in the wasp and bee order - Hymenoptera. Bt will not work on anything except Lepidoptera, except for Bt var. israellensis which is used for mosquito larvae which are in the order Diptera (flies and mosquitoes). So Bt is too specific to work on sawflies. DE, on the other hand, is not specific at all but kills anything soft bodied including any soft bodied larval predaceous insects such as ladybugs, syrphid flies and lacewings. As well as being damaging to our lungs when we breathe in the dust while working with it. The insecticidal soaps and neem oil sprays unfortunately are also as damaging to these beneficials as they are to any pests.

Thanks for the info everyone, I'm taking notes...

Barb

Thanks for the info everyone, I'm taking notes...

Barb

knottyceltic, I'm wondering what you tried and did it kill the lgm (little green monsters)?

I have a shrubby native dogwood of some type which gets denuded every year. The "worms" appear in their early stages as white flecks, after the plant blooms, which grow in size and turn green. If you wait until they are green it is too late. I usually did not notice until the infestation was well underway. This year, out of desperation, I took a small spray bottle, filled it with straight vinegar and a dollop of Ivory Soap .. and sprayed the area with the first tiny white "worms" I saw. The ends of a few branches were damaged so I cut them back and discarded them. The "worms" fell off so I misted the entire plant. As it was dry and hot I did not reapply. A few leaves browned a bit where I got them too wet.. but I saw nothing for about six weeks. A tiny number of hungry critters started to appear on one branch so I re applied the treatment. It is almost September and my shrub is hale and healthy ..In past years it is just sticks by now. Vinegar is cheap and reasonably natural. but you have to catch the outbreak early on.