Weed Wars...With Lasers!

You may finally get the chance to finally obliterate those pesky weeds using some of the advanced technology in Star Wars and Star Trek. Researchers in Hannover, Germany are finding ways to utilize lasers to zap and radiate weeds in an effort to discover safer alternatives to herbicides.

The CO₂ laser is being developed at the Laser Zentrum Hannover eV (LZH) and the Biosystems and Horticultural Engineering Faculty of Leibniz University in Hannover.

The researchers at Leibniz University use a stereo camera system to optimize the laser's position on a set of rails once it has identified the plants. Then, using a method they developed, the two cameras compare their images and form their own idea of the active outline of the plant. Next, simply set the coordinates (a la Star Trek) and zap! The accuracy in lab conditions was within one millimeter, and in a greenhouse, within three millimeters.

Plants are directly receptive to the thermal radiation generated by this laser - seedlings can be killed using a dosage of 35 Joules. The laser has to be programmed to the plants' ages and species in order to effectively rid them without causing unintended consequences.  In fact, if given too much laser light, the plant thanks you, and unintentionally thrives.

The demand for environmentally safe alternatives for herbicides is increasing as people become more aware of the strains put on the very fields they are trying to sow. Chemical herbicides are turned to when old, thermal methods, such as a fire, are not viable. Often times the residue from the herbicides stays in the topsoil and surface water, damaging wanted crops, or in extreme cases, seeps down into the ground water, where it can do damage to humans.

At its current stage, the laser can successfully treat around one square meter of growth in a greenhouse. The real challenge now will be to figure out how to treat a large, open area. Farms and ranches have no ceilings with rails that one can mount a laser on - but with the precision of the U.S. Army's military technology, there's no reason an aerial-laser-drone strike on those invading weeds in your backyard that it might not become a reality.