Here is another way to accomplish the task: Cover each of your roses with plastic bags that your daily newpapers arrive in. Twist tie them on. Spray the rose with Spinosad. Then remove the plastic bags. This is worthwhile to save the bees. I have never seen bees land on the leaves of roses, only on the flowers. Spinosad does indeed kill rose slugs. You will feel good that you are getting rid of the rose slugs but also protecting the bees.

Rose slugs are the larvae of rose sawflies. (There is more than one kind of sawfly.) Sawflies emerge from the ground under the rose in spring. They mate and lay eggs under the leaves on the rose. The larvae emerge and chew on the rose leaves, then fall to the ground and pupate and another generation of sawflies emerges in spring. Usually this happens here in May or early June continuing on into July. It would be a good idea to mark on the calendar next year when we first see the rose slugs. If we can figure out the timing of the life-cycle of the sawfly then we have a chance to stop them in their tracks. It’s all about timing the spreading of the dry worm castings ahead of the time the adults emerge from the ground. Diatomaceous earth might work if placed on the ground at the right time but the problem with that is that once it gets wet it doesn’t work. The important thing with rose slugs is to “stop them at the pass” and accomplish this in an organic way.

Now to explain about the worm castings. Dry bagged worm castings laid down like mulch on top of the ground in spring ahead of the time the rose sawflies emerge do cut down or even stop rose slugs in spring but this has to be timed properly. If done early in the year the sawflies cannot emerge from the ground under the rose. Having worms and seeing the “poop” as you call it on top of the soil doesn’t stop the cycle because the emerging saw flies go around it and fly up onto the stems of the rose plants to lay their eggs.
It is the dry worm castings themselves that kill insects (in this case sawflies) as they try to emerge from the ground. Once they have emerged they will mate and fly up onto the rose, but these hatching flies cannot get through the dry worm castings because the worm castings kill insects on contact. (I have not tried making a worm-casting spray by mixing worm castings into water. Some people do this and say this also works but I have never done this, so I can’t guarantee results.)

As far as other sprays go, some people say Neem oil and Pyrethrins kill rose slugs but of course Pyrethrins are poisonous sprays, even though natural and Neem oil has never worked for me. There is an organic spray made by Gardens Alive called Pyola. You might try that against rose slugs. It might work, but I am not sure. I cannot guarantee that Pyola kills rose slugs.

I fear that chemical companies are destroying our precious planet. I believe we come back to Earth more than once and must take care of it for future generations and that we are those generations to be. So we should do this for ourselves. My next book (already completed) will make this philosophy clear. Even if people don’t agree with me, perhaps it will awaken some thoughts about what we humans are doing to this magnificent world.

We like to think that there is at least one person FOR the bees for every person oblivious. Thanks for being there!

Our only real problems this year have been consistently severe powdery mildew (especially on the cukes). I will use Serenade from now on to prevent. And I will look for PM resistant varieties next year. However, I am currently trying a tea made from cornmeal, on the advice of a friend. Apparently, it encourages good fungus that kills powdery. Do you know anything about that?

Anyway, I wanted to write this to let you know that bees are alive, well and simply thriving here in our little plot in West LA, just north of downtown Culver City. Bumblebees, and wasps too. And lots of ladybugs! I just needed to compliment your article with some good news!

Thank you for everything you do. We love our bees and will never use Spinosad, since we have plenty of wasps.