From the Invasive Plants in Sourthern California blog (http://ucanr.edu/blogs/socalinvasives/index.cfm)

This blog should be filed under, “They'll try anything, especially if they think there is lots of money in it and they don't know the business.”

Since I moved from an agricultural assignment 14 years ago in the low desert to do invasive plant extension work I have seen a whole bunch of strange ideas and practices floated out there that are sexy, but don't make sense. These have included steaming with a sugar-enhanced foam, tons of sugar dumped on the soil to fool soil bacteria (they would gobble up all the available nitrogen so the weeds didn't have any and the natives would then be competitive) and high-pressure water sprays. All of these worked to some extent, but they were all way too expensive for the benefit they provided. And they were only useful on small annual weeds.

Well, I thought you might find the idea of electrocuting weeds as entertaining. I haven't seen this one in wildlands yet, but I bet someone, someday is going to promote it as a great new method. These two photos were taken in the 1980's at a field demonstration of the Lightning Weeder. The field is sugarbeets and the weed is annual sunflower.

The photo to the left shows the ‘business end' of the device; the blue box is a 2500 volt generator, which charges up the steel bar beneath the coils. The bar is lifted to a height that contacts the tall sunflower but doesn't touch the shorter beets. The photo on the right shows the large arc generated when the bar touched a plant, kinda scary and we were all told to stay well away from the electrocutor.

The sunflower plants were fried, literally, they were too hot to touch. So what was wrong with this? It worked, right? For one thing it was very expensive, dangerous and required a very large tractor to run the generator. But the biggest problem is that killing a weed this late in the crop production season is not weed control, it's revenge; the yield loss caused by competition to the beets has already happened. So you spend lots of money for no benefit. The people that created and were promoting the lighting weeder were engineers and they apparently never bothered to talk to any agricultural scientists or practitioners before they sunk their money and time into their contraption.

And this wasn't the first time this had been tried. The photo below was taken sometime in the 1940's or so (I inherited this photo and don't know its history, but the lettering style on the generator is old, as is the tractor pulling it). This wasn't a weeder, it was meant to be used to thin a crop (probably lettuce) by electrocuting the unwanted plants in-between. It might have worked and today computer-controlled, tractor-based thinners are being used in lettuce and similar crops, but I never ran across one of these in the desert valleys.

 Anyway, stay skeptical, there are no silver bullets, just lots of blanks and people willing to sell them to you.