Drones, Bug-Bombs & Future Weed Control

FUTURE WEED CONTROL, looking out several decades, will inevitably by necessity gradually start shifting towards weed-eating insects for biological control, with a lesser mix of herbicides and tillage. Drones delivering “Bug-Bombs” with payloads of beneficial weed-eating insects may not be the fastest or deadliest means of killing weeds, but it is an ecological strategy with many benefits for fighting weeds in remote terrain, rangelands and large, hard-to-reach areas in general.

Yong-Lak Park, a West Virginia University (Morgantown) entomologist, calls it “Shooting insects from the sky: Aerial delivery of natural enemies using aerospace engineering.” At a late-night session of the KYE (Korean Young Entomologists) in Austin, Texas as part of the Entomological Society of America (ESA) annual meeting, Park’s informative slide show (now posted on the Internet) depicted a range of Unmanned Aerial Vehicle (UAV) designs and even a California vineyard in the agricultural vanguard with its own drones (not unlike flying model airplanes). Indeed, it is not hard to imagine a New Feudalism, where behind moated walls with locked gates and barking dogs, in an entertainment room with big screens and small monitors, sit modern medieval lords with joy sticks in hand commanding drone armies and air forces trying to rule universes, suburban lots and whatever.

Like model airplanes, UAVs are lightweight, inexpensive and relatively safe and easy to control, Park told the room full of Korean entomologists and a lone non-Korean writer in attendance. Equipped with sensor modules, GPS, digital cameras and video image analysis capabilities, UAVs can monitor weeds and detect weed biocontrol weevils on the ground with a resolution of up to 3 inches (8 cm). UAVs similar in design to the infamous drones used by certain governments for extrajudicial killings, and small helicopter-like octarotors are among the aerospace vehicles capable of delivering beneficial “Bug-Bombs” (bug pods) to large, hard-to-reach areas for biological control of weeds such as morning glory and mile-a-minute weed (Polygonum perfoliatum).

Galileo’s legendary sixteenth century scientific experiment dropping objects from the Leaning Tower of Pisa to see how fast they fell came to mind when Park described his rooftop tests dropping Bug-Bombs filled with weed-eating weevils from different heights. Only rather than challenging Aristotle’s ancient teachings, Park wanted to see if the bug pods, which are cannisters shaped like the bombs you see dropping from Allied planes in World War II film footage, would cushion the weevils when they hit the ground from different heights. Indeed, 80-90% of the beneficial weed-eating weevils inside the bomb-shaped pods survived being dropped 0, 10, 20 and 30 meters (0, 33, 66, 98 ft). The idea being that the pods pop open when they hit the ground in some remote weed-infested area, and the weevils hop out and go about their everyday life of eating their favorite weed and reproducing new generations of weevils.

Basically, you get an army of weevils on the ground doing weed control, as opposed to aerial bombardment with herbicides and all their environmental side effects. This is known as classical biological control of weeds, and it has a long track record. On the downside, it is expensive to find the right insects, as they must be collected, reared and tested to make sure that they stick to the weeds (so you don’t inadvertently introduce a crop pest, for instance). Then you need permits. It might be millions of dollars and decades later before all the hurdles are leaped and a successful program is out the gate. But it has worked against several dozen weeds, and often a successful program can then be easily replicated in a new location.