Farmers will sometimes use a mesh fabric instead of insecticides to protect their plants. NC State scientists have developed a new material that keeps a broader spectrum of insects out while allowing crops to obtain enough sunlight and water.
When farmers cover their plants with crop-cover materials, the size of the pests kept out is determined by the size of the gaps in the mesh. Unfortunately, tobacco thrips are so tiny that they can easily slip through the holes in existing materials. However, if the gaps were made small enough to keep the thrips out, the plants would not get enough air, sunlight, or water.
With this in mind, scientists at North Carolina State University (NC State) have created an experimental “Plant Armor” as a more effective alternative. It’s made up of three layers of knitted fabric. Layers of transparent plastic yarn are used on the outside and inside. Another knitted layer is sandwiched between them, its fibers running perpendicular to those of the other two layers. Even if insects are small enough to get through the material’s surface, the maze-like internal structure will make it super challenging for them to get all the way through.
For example, in one experiment, groups of 10 thrips were placed in a Petri dish with a cabbage leaf either protected by an existing crop-cover material or a piece of Plant Armor. The insects got through the crop-cover material in only 12 minutes, whereas it took three hours to get through the Plant Armor.
In another lab test, unfed caterpillars were placed in a cage with Plant-Armor-covered and unprotected potted cabbage plants. Even after ten days, no caterpillars were observed on the unprotected plants, which were immediately infested and nearly totally consumed. Furthermore, when researchers grew cabbage plants in a field either uncovered or covered, the covered plants were three times heavier and larger after a three-month growth period.
Since the Plant Armor does not rely solely on small gap sizes, plenty of water, sunlight, and air can still pass through. And according to doctoral candidate Grayson Cave, the material is reusable and can also be made from recycled materials.
Cave, the study’s first author, said:
“We found it’s possible to use this new technology to protect against insects we didn’t think we could protect against. We’ve shown we can use a mechanical barrier that will protect against tobacco thrips and possibly other insects, allowing the plant to grow and thrive underneath.”
The study is detailed in a paper published on March 31 in the Agriculture Journal.
