Drones, Bug-Bombs & Future Weed Control

February 21, 2014

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.

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Doggone Birds (Fruit Protection)

September 13, 2012

Many bird species provide biocontrol by eating a wide range of insect pests, and are worth encouraging for controlling flies, mosquitoes, locusts, caterpillars, ticks, rodents and other pests around homes, forests, farms and gardens. Other bird species are considered pestiferous when feeding on our food plants, and can be repelled in various ways, including by loud noises, eyespot balloons, reflecting tape, scarecrows and scare devices, sensor networks and dogs.

Among the beneficial birds when they are not causing damage to utility poles or annoying people with their racket are woodpeckers. Personally, I like hearing woodpeckers working urban and forest trees, and was heartened to learn from Michigan State University’s Andrew Tluczek’s presentation to the Entomological Society of America (ESA) annual meeting that: “Woodpecker predation has caused up to 90% mortality of emerald ash borer (Agrilus planipennis) larvae in some sites.”

A 2006 tick control article in BioScience magazine devoted considerable discussion to birds for tick biocontrol. In Africa, birds known as oxpeckers (Buphagus spp.) provide biocontrol of ticks on mammals by consuming hundreds of adult ticks or thousands of nymphal ticks per day. Free-ranging guinea fowl experimentally tested around New York (USA) lawns reduced adult blacklegged tick numbers; but unfortunately the smaller nymph stage blacklegged ticks transmitting Lyme disease apparently were missed and not stopped very well.

The list of bird benefits for biocontrol, like barn owls for rodent biocontrol in Israel, Palestine, Malaysia and elsewhere could go on and on.

“Bird damage situations throughout the world are similar, involving many of the same crops and genera of birds,” wrote John W. De Grazio a few decades ago in the <em>Proceedings of the 8th Vertebrate Pest Conference. Seed-eating red-winged blackbirds, ring-necked pheasants, sparrows, crows, doves, parrots, munias, queleas, weavers and waterfowl are sometimes pests of corn, rice, wheat, sorghum, sunflowers, almonds, pecans, peanuts, etc. Starlings, sparrows, finches, grackles, robins, parakeets, etc. consume grapes, blueberries, and other fruit in yards, vineyards and orchards.

Dogs are used in pest control for sniffing out termites and bed bugs, and the natural proclivity of some dog breeds to chase birds can be harnessed to keep birds from destroying fruit in orchards and vineyards. In researching a grant proposal to travel to and write about Japan, which I failed miserably to qualify for, my Internet research for the proposal took me to the Japanese Journal of Farm Work Research. Being one of a select 4% of the USA population to have worked in agriculture, the journal title intrigued me enough to browse through several years of tables of contents, where I came across an intriguing article title: “Protection of Citrus From Bird Damage by a Dog.”

Not reading Japanese, I had to rely on the visual diagrams and English summary by researchers Hiromichi Ichinokiyama and Masami Takeuchi at the Kinan Fruits Tree Laboratory and Mie Prefectural Science and Technology Promotion Center:

“Effectiveness of a dog (Canus lupus familiaris) for protecting citrus fruits from bird damage was investigated using a citrus orchard (5.8 a in area) in the harvest season. In Experiment 1, a Border collie shepherd (male) was tied to a wire extended along one side of the square orchard to allow him to run along the inner side of the orchard. This watchdog system was effective in reducing fruit damage by birds (mainly brown-eared bulbul) only in the citrus tree row nearest to the dog runway.”

However, the researchers had better success letting the dog run free in the orchard:

“In Experiment 2, the orchard was enclosed with a tall chain-link fence and the same dog was allowed to move freely in the orchard. In this case, he persevered in chasing birds until they flew away from the orchard. This watchdog system effectively reduced bird damage to citrus fruits all over the orchard, resulting in an increase in crop yield…Further study is needed on the optimum number of dogs released per unit orchard area and the effectiveness of the watchdog system in case when this bird control system is spread to all orchards in the citrus-growing area.”

Like Richard Feynman’s Nontoxic Ant Ferry, dogs chasing birds away from trees laden with fruit or nuts is more a proof-of-concept awaiting further development than a fully developed technology you can order on the Internet.

Thank you to the organizations and people who created and are advancing the Internet, as even finding this sort of information would have been nearly impossible a few decades ago. Amazing how this high-tech infrastructure can advance low-tech solutions like the old-fashioned four-legged, tail-wagging dog as a bird-chaser in service of better fruit harvests.