Just so you know, organic pesticides kill both bad and good insects. They can't tell if it is bad or good just because they are natural.

You would spray as often as necessary, but if that was more often then once a week I would be looking at why. Is the soil good and healthy so those plants can grow strong and healthy? Does the environment the plant is growing in an environment the plant needs?
As Minnie has already stated spraying any insecticide can kill off the beneficials as well as the pests.

I don't think you understand how a soap-and-oil spray works. It only kills the insects that have actually been coated with it. If you don't spray it on, say, a ladybug, that bug will not be harmed. I don't know how much a deterrent it is once it's on the plant if it's just plain soap and oil with no garlic (see below.)

It's true that while I'm spraying for spider mites, I can get some lacewings, but quite frankly, if the lacewings had been doing their jobs, I wouldn't have spider mites!

The garlic is supposed to repel spider mites and aphids. I don't know if it does, but it definitely doesn't repel ladybugs, mantises and bees. It definitely DOES repel mosquitoes. There is an organic anti-mosquito spray on the market made only from super-concentrated garlic that is very effective for mosquitoes but has been proven to be harmless to all beneficial bugs, bees and birds.

I don't think you understand how a soap-and-oil spray works.

Oh yes we do but we also know first hand the damage they can do to plants as well as beneficials. The effects of many 'home-made' recipes - both good and bad - has been well documented.

How often you spray would depend entirely on what the recipe you are using. There are many floating around and some do more harm to the plants and beneficials than any effect they might have on pests.

And as kimmsr said more than once a week is normally considered too often and a clear sign that it either it isn't working or that something else is causing the problem.

Blithely using home-made recipes with little understanding of exactly how they work or the long term effects is no better than indiscriminately using chemical pesticides and in some cases can do more harm.

Dave

You may want to read this on the control of Spider Mites.

Here is a link that might be useful: About Spider Mites

Kim -- Thanks for the great article! It's more complete than the other articles I've seen. I'm happy to see that, according to this, I was definitely dealing with the spider mites in the correct way. Chemical insecticides kill everything BUT the spider mites, which go nuts; water+oil and/or organic vegetable-based soap is the recommended treatment.

The article also answered a question I thought of this weekend: If the idea is to smother them, why do you need soap in the oil spray? Sure enough, the article talks about using insecticidal soaps OR insecticidal oils. It also talks about the importance of hosing plants off well with just plain water (which I do to knock off as many as I could) and keeping dust off of them.

This post was edited by GreenDreamhome on Mon, Apr 21, 14 at 11:40