The Riverside Press-Enterprise
New hope against weeds, soil pests
Three innovations in the plant world may offer pleasant surprises for farmers, backyard gardeners and indoor plant enthusiasts.
Spraying chemicals for weed control has apparently run its course. The problem is that, until now, every herbicide application program for weed control has failed. This failure is expressed in the resistance of weed species to the chemicals meant to eliminate them.
Strains of the bothersome weeds suddenly appear that have developed resistance to the herbicides in question. To accommodate stronger herbicides for agricultural use, cotton, corn and soybeans were bioengineered for resistance to one widely used product. Now you could spray your fields indiscriminately without concern that your crops would be affected. Yet eventually weed resistance was observed in these fields, too.
An artificial intelligence-generated solution was then devised for weed abatement where a minimum of chemical use was involved. A robot was created that could distinguish between weed and crop seedlings. Tens of thousands of images of cotton seedlings, for example, were laboriously produced. These images were then uploaded into a robotic weeder that attached to a tractor. The weeder would scan every seedling in its path, ignoring anything that resembled one of the archived cotton seedlings. Meanwhile, a micro-jet of herbicide was directed onto each weed seedling. It was even conceivable that just as a robotic lawn mower could be used for cutting your lawn, a robot for weed control around the house could someday be put into use as well. The problem, of course, was that herbicide use was still a requirement for robotic weed control.
But now a biotechnological technique has been introduced that could at long last solve our problem with weeds. It has been shown that weed pollen subjected to gamma rays — when applied to the same species’ female flower parts — produces sterile seeds. Most of the work has been done on Palmer amaranth, which is a major weed in cotton and soybean fields. A single Palmer amaranth weed growing in a cultivated
field may produce between 10,000 and 60,000 viable seeds.
Successful application of irradiated Palmer amaranth pollen has been conducted on test plots in Israel and the United States with positive results. Imagine scattering irradiated dandelion and crabgrass pollen over your lawn and seeing these weeds cease to proliferate. (Note: Radiation to prevent bacterial growth on fruits, vegetables and meat was approved by the FDA over 30 years ago.)
From weed control to insect control, a solution utilizing parasitic nematodes has proven itself against fungus gnats, the most pesky indoor plant pest. Nematodes are not true worms but are sometimes referred to as roundworms because of their curved, roundish bodies. There are estimated to be 1 million nematode species, with 15% of them parasites of animals or plants. They range in size from a millimeter to 6 feet in length, although the ones that parasitize insects are microscopic. In a juvenile state, their mouths are sealed as they wriggle through the soil, eventually finding an insect larva or adult to penetrate through the victim’s mouth, anus, spiracles (air vents for breathing) or openings in their exoskeleton. After entering its host, the nematode poops out pathogenic bacteria that soon liquefy the host’s body. While we are on the subject, there is a bacteria (Bacillus thuringiensis Israelensis) that not only kills fungus gnats but mosquitoes. The above nematode and bacteria
products are readily available through Internet vendors.
Utilizing nematodes for insect control is a science in its infancy. Nematodes have demonstrated their prowess in parasitizing hundreds of insect pests, and they’ve shown promise for protecting commercial vegetable crops and fruit trees. At the same time, nematodes can be damaging to crops. The root-knot nematode is famous for infesting the roots of tomatoes, cucumbers, squashes, carrots, and papaya and peach trees, but corn is resistant. The live, beneficial nematodes in Tip Top Fungus Gnat and Rootknot Exterminator control the two pests indicated in the label as well as other insect pests that dwell or lay their eggs in the soil.
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A Daily Breeze reader informed me of an innovation in the world of horticulture that brightened my day and may soon brighten my night as well. It’s the introduction of a plant that glows in the dark. To be precise, it’s a bioluminescent petunia with white flowers that goes by the name of Firefly. The name appears to be an ode to the first bioluminescent plant that was engineered, in 1986. A gene that manufactures luciferase — that confers the firefly insect’s ability to exhibit flashes of light in the dark — was inserted into the genome of a plant in the tobacco family that subsequently glowed. At the time, there was interest in the commercialization of the glowing tobacco plant, but the light it created was rather weak, and special plant food was
needed to produce the desired illumination.
Interestingly enough, tobacco and petunia are both members of Solanaceae, the nightshade family, so perhaps there is a proclivity among this group to accept bioluminescent genes. In the case of the Firefly petunia, the glow-in-thedark gene comes from a mushroom, but no special fertilizer or growing conditions are necessary. The light produced is not brilliant but definitely provides a moonlight type of glow. Firefly petunias, suitable for growing both indoors (as long as they get plenty of light during the day) and outdoors, will be shipped from the Light Bio company in Sun Valley, Idaho, beginning in April. You can order them online at light.bio.
••• Speaking of genetic modification, the first food plant to undergo bioengineering and be marketed to gardeners is available. It’s a purple tomato that was made by insertion of a snapdragon gene that produces anthocyanin, a purple plant pigment and antioxidant, into the genome of the tomato, another nightshade. You can acquire purple tomato seeds, from which you will grow large, deep purple cherry tomatoes, at norfolkhealthyproduce.com.