Originally Posted By: redewenur
There's only so much useful speculation to be done here regarding detection. But apart from the detection issue, there are other problems. These little guys would need to be capable of rapidly traversing soft and uneven terrain, and of killing weeds by some as yet undetermined method. They would also need a sufficient power source.

Exactly - if it were easy and affordable, it would have been done already. We've seen some gigantic leaps forward in a lot of technical areas of the past decades, and with time robots like this will be made with cheap, off-the-shelf-hardware.

Today, unfortunately, they are not.