According to the advertising hype about these pest repelers they emit an ultrasonic sound that you cannot hear that either drives the target pest away or kills them. There is no real good evidence they work and my experience is they do not work. The same thing applies to those windmills or solar powered mole/gopher repelers that are supposed to emit a low, or sometimes high, frequency sound that repels those buggers, there is no evidence that they really work.

What kind of insects are you trying to kill? If your trying to get rid of Aphids, a mixture of water and dish soap works well.Just spray your Banana plant with this and it will kill them!!! Diana

I haven't posted in a long while, but admittedly, this is a subject that is unfortunately dear to my heart. For a couple years now I have gotten hit pretty hard with mites. Like real hard. Hard to a point where ALL the leaves turn yellow and fall off. Not all at once but within a matter of 1 week I've had brugs and other perennials like honeysuckle go from being lush and green to yellow, spindly and sick. Here in central CA it can happen and happen fast. This year I vowed to stay on top of things. I sprayed neem every 5 days. I sprayed Bt once a week to prevent worms. I was so pleased that again this summer that a good 'crop' of praying mantis were out and about enjoying their feasts. ---I realize the mantis's actually do not prey on mites - but I'm pleased that their presence along with the lacewings are the healthy by-product of an 'organic' approach. Well, given that technically neem shouldn't be used in direct sunlight and/or in temps above 80, that was literally impossible to uphold seeing that our low nighttime temps recently have not been below 90. So, in an effort to squelch the mites, I sprayed neem as late (or early) as possible and now I'm afraid I could have lost 2 brugs. Both have lost every leaf and they're turning brown at the tips. This is horrible! I want to say that neem and other organic measures are the way to go, also, but I'm afraid that in some cases of extreme or sustained dry heat, it just doesn't work. I've tried the spraying water thing, too. Getting a water ticket is not a good option. I have now ordered Avid which is a miticide that apparently is very, very popular on the Rose forums. It's not cheap, but I'm literally desperate. It's supposed to have very low phytotoxicity and it does not hurt beneficials. This really is important to me, hence probably why I've continued to try for so long without succumbing to more toxic methods. I'm going to see how the Avid works. Mites here in central CA are the bain of my gardening experience!

I agree with rhizo_1. I find it somewhat conflicting that some folks try to avoid a product because of a particular substance (DEET in the case of insect repellent) in the formula, but the same people don't seem to have a problem rubbing other products all over their skin, simply because of something they read on the 'net or received in an e-mail. Even worse are the people who loudly complain "independent lab tests" show why you shouldn't use "this product" but feel compelled to experiment (or get somebody else to) with all sorts of novel uses of a product, in ways it was clearly not intended for. Oh well, I guess it's just the "modern alchemy". Tell you what there Merlin, when it becomes apparent at some point in the future, that a typical ingredient in your common fabric softener can lead to cancer, convulsions, or coughing, will you please stand up and proclaim just as loudly, that you were instrumental in spreading the malady?? Just this week, my wife received an e-mail proclaiming that people should keep a can of "Wasp Killer spray" in their purse, or car, or home, instead of "Mace" or "Pepper Spray". The main "point" of why to use wasp killer was because of the longer range afforded by it compared to pepper spray or mace. While I have no sympathy for muggers, robbers, or other thugs, I can't help but think that encouraging people to "keep wasp killer handy" will result in accidents involving children. My opinions.