NC State's 'Plant Armor' fabric tripled strawberry yields in field tests — and started as body armor

A knitted fabric originally designed to make body armor more comfortable for soldiers has, after years of trial and error, tripled strawberry yields in field tests at North Carolina State University — without adding pesticides, blocking sunlight, or trapping excess moisture.

The material, called Plant Armor, is draped over strawberry plants like a tent. Its three-dimensional, multi-layer structure creates a maze-like barrier that insects cannot easily navigate, while still allowing sunlight, rain, and airflow to reach the plants beneath. In tunnel field tests running from November 2024 to May 2025, covered plants produced 3.56 times as many harvestable strawberries by count and 1.84 times more by total weight than uncovered controls, according to a paper published in the journal Agriculture in September 2026.

The trial was conducted at NC State's Research Annex in Raleigh using the Sweet Charlie cultivar — an early-season variety. Three raised beds were each split into a covered half and an uncovered half, with four plants per section. Researchers picked ripe berries by hand every other morning through spring. Covered plants were ready to harvest about a week earlier than uncovered ones.

To produce fruit, plants need sunlight. We expected that Plant Armor's seemingly opaque fabric would lead to an increase in vegetative biomass at the expense of fruiting — because reduced sunlight would trigger a 'shade-avoidance' response, making the plant divert energy toward stem and leaf growth rather than fruit production. However, we found the fabric did not impede access to light at all, and fruit production increased significantly.— Gabriel Olawuyi, graduate research assistant and lead author, NC State University

When covered plants were dug up and weighed, there was no significant difference in leaf, stem, or root biomass compared to uncovered plants — meaning the fabric did not trigger the energy-diverting shade response the team had feared. What it did do was hold heat. The air under the fabric averaged about 1.93 °C (roughly 3.5 °F) warmer than in the open plots, without raising relative humidity — a meaningful distinction, since trapped moisture can invite disease.

Plants require a certain amount of accumulated heat, calculated as 'growing degree-days,' to progress through developmental stages including fruiting. Our plant cover has proven to enhance these. The plants were in a condition whereby the warmth they need to go through each phenological stage to their production was given to them optimally, and they produced far more than the uncovered plants.— Gabriel Olawuyi, graduate research assistant and lead author, NC State University

The insect-blocking properties were tested separately in laboratory bioassays. When young aphids of the species Rhodobium porosum were placed on top of the fabric with a strawberry leaf below, none made it through during a 180-minute test — what the authors describe as absolute aphid exclusion — even though a standard fly screen did not stop them. In the field trial itself, aphids did appear on both covered and uncovered plants in March 2025, and both groups were sprayed once with insecticidal soap. The researchers suggest the insects may have arrived on transplants as overwintering eggs, or entered when the fabric was lifted to take temperature readings. The pesticide-reduction benefit, while plausible, was not directly measured in this trial.

The fabric's origins are a study in how research crosses disciplines. Plant Armor Gen 2 — the version tested here — grew out of work to develop military textiles resistant to mosquito bites and comfortable enough to wear under body armor. It is patented by NC State (US Patent No. 11,582,968 B2, issued February 2023) and licensed for commercial development. The patent describes an outer and inner polyester layer joined by connecting filaments, with outer-layer pores of roughly 50 to 100 micrometers and 30 to 80 millimeters between the layers — the geometry that creates the winding path insects struggle to navigate.

The path to Plant Armor started with trying to make a cloth to go on a soldier's chest to make body armor more comfortable. Then, through trial and error, we arrive at a product which could triple the output of strawberry farms here in North Carolina. We couldn't have predicted that when we started. Without all these people here doing research and following the science, we wouldn't have arrived at this product.— R. Michael Roe, William Neal Reynolds Distinguished Professor, NC State University

The project was a collaboration across NC State's College of Natural Resources, Wilson College of Textiles, and College of Agriculture and Life Sciences, and was supported by a grant from the North Carolina Agricultural Foundation and the U.S. Department of Agriculture's National Institute of Food and Agriculture.

Plant Armor is not the first row cover used on strawberries. Ordinary single-layer covers made of polypropylene or polyester are already used in the industry to protect flowers and fruit from frost. What distinguishes Plant Armor is its three-dimensional spacer structure, which previous single-layer designs lack. Earlier NC State research using the same 3D fabric concept on cabbage found a 2.93-fold increase in vegetative growth and resistance to insect penetration, though that study did not examine fruit production.

The results are promising, but the researchers and independent observers are careful about scope. The trial used one cultivar at one site over a single winter season, with twelve covered plants per treatment arm across three beds. The NC State release and the paper itself frame reduced pesticide and water needs as potential benefits, not measured outcomes. The paper calls for on-farm testing across a variety of crop plants and geographical locations. A commercial grower would also need to know how the cover performs across full seasons, at field scale, and whether the warming effect that helped early fruiting in a cool-season crop becomes a liability as spring temperatures rise — none of which the current paper addresses.

Why it matters — If results hold at commercial scale, a passive physical cover could let strawberry growers significantly cut pesticide use and boost yields without changing their underlying farming practices.

Sources differ on Whether the trial spanned three growing seasons or one: Three growing seasons — strawberries grow over fall, winter, and spring, which the trial covered as a single continuous season (news.ncsu.edu) vs A single trial from November 2024 to May 2025; some coverage incorrectly described this as three separate growing seasons (morningoverview.com)

Reported by goodnewsnetwork.org, news.ncsu.edu, ecoticias.com, blog.mdpi.com, knittingindustry.com, morningoverview.com