The larva should be pupating now so you can cease the spraying. Check the soil those plants are growing in to be sure it is a good, healthy soil so the Columbine will be less atrractive to the adult sawfly.

Thanks. I am working on beefing up the soil - good to know that will help with the larvae. For next year, though, can you tell me when, during the summer, I can expect the danger to go away? I understand that it will gone away by Sept 25 :-)..... But how early before that?

Beefing up the soil is not likely to make an impression on your sawflies, which are species specific plant pests. They will seek out columbine as their host plant in order to perpetuate the sawfly population. The adult sawfly doesn't care one single bit what kind of soil their host plants are grown in, nor what kind of shape they're in. ;-)

However, plants that are healthy are better able to tolerate an infestation and recover quickly.

I would have thought that the sawfly larvae would have been long gone in your location. As a matter of fact, I'd guess that they have pupated already and have flown away as adults. There is only one generation per year.

Next year, why don't you consider using a product with Spinosad as the active ingredient? Rather than acting as broad spectrum pesticides, spinosad works effectively on leaf chewing insects. It's a bio-control agent that the pest must ingest.

That way, your beneficial predators and parasitic insects will have a fighting chance at survival and be able to help you control those darned sawflies.

Many people wrongly assume that a good, healthy soil that grows strong, healthy plants will not help deter insect pests and diseases, because they have not gotten there and have not seen that. Numerous of todays garden writers, including Rebecca Coles, Lee Reich, even Elliot Coleman have all written that developing a good, healthy soil will help deter plant problems. Getting your soil into that good, healthy condition can also be a money saving means, as well as a more environmentally sound practice, of growing plants since you will not be spending your money on poisons to get rid of insect pests that are not coming to your garden.

Sigh. Here we go again. Kimmsr, put your listening ears on!

Those insects that require a particular species of plant in order to complete their life cycle will seek out that plant and use it for its purpose no matter what. It does not matter if that plant is in perfect condition and is thriving in the best of soils. The columbine sawfly is just one example.

This is one aspect of IPM that you seem to have little understanding of, Kimmsr. There are many species specific pests out there. We can eliminate those plants from our gardens, or we can take it upon ourselves to learn the life cycle of the pests so that we can mitigate the damage.

No one has said that a 'good healthy soil that grows strong, healthy plants will not deter insect pests and diseases'. (I know that you're trying to insult me, but you'll have to do better than that, lol.) But you shouldn't turn your back on the facts. There ARE very susceptible plants out there just as there ARE plant pests that will seek and find their particular host plant.

It's very important to provide a vital and healthy soil system. The benefits are huge. And many insect and disease pests are able to take advantage of plants that are weak, under or over nourished, or simply languishing.

But it's important, too, that we understand the behaviors and life cycles of some pests. By doing so, we can avoid those plants entirely, should we wish to do so. But for those particular insects, seeking out the appropriate plant species is instinctual...just as much as a mosquito seeks a blood meal.

I never try to insult anyone. However, Rhizo, you did just confirm what I said.