A knitted fabric designed to keep insects away from crops raised strawberry yields by as much as 3.56 times in tunnel field tests at North Carolina State University, researchers report. The cover, called Plant Armor, blocked aphids completely in laboratory tests while letting sunlight, rain and air reach the plants.

The study, published Sept. 24 in the journal Agriculture, found that covered strawberry plants produced significantly more fruit, both by number and by weight, than uncovered plants over three growing seasons from fall through spring.

For farmers, the appeal is a physical barrier that could reduce the need for chemical sprays — a goal shared by growers, farmworkers and consumers who want fewer pesticide residues on fresh fruit. Strawberries are a high-value crop that is attacked by many insect pests, so even a partial reduction in spraying could matter to growers' costs. The researchers caution, however, that the results come from tunnel tests in North Carolina and must still be confirmed on working farms.

A Maze Insects Cannot Solve

Plant Armor is a three-dimensional spacer fabric with multiple knitted layers. Instead of a simple mesh, its structure forces insects through a winding path. "The insect has to figure out how to get through the maze to get to the plant,"senior researcher R. Michael Roe, a William Neal Reynolds Distinguished Professor at NC State, said in an earlier university report on the technology.

The fabric is porous, so air and water pass through, as trade publication Knitting Industry noted in its review of the knitted structure. In lab bioassays, it achieved what the authors describe as absolute exclusion of aphids, small sap-feeding insects that damage strawberries directly and can spread plant viruses.

The technology has an unusual origin. It grew out of NC State research on making military uniforms resistant to mosquito bites and making body armor more comfortable. "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," Roe said in an NC State announcement.

Shading That Did Not Hurt Fruiting

The team expected the cover to reduce fruit. Plants that sense shade often put energy into stems and leaves instead of fruit, a response called shade avoidance. The fabric looks nearly opaque, so lead author Gabriel Olawuyi, a graduate research assistant, anticipated that problem.

"However, we found the fabric did not impede access to light at all, and fruit production increased significantly," Olawuyi said. The study found no difference in vegetative growth between covered and uncovered plants, and no shade-avoidance response.

The cover also kept plants consistently warmer. Plants need a certain amount of accumulated heat, measured in growing degree-days, to move through each growth stage. Olawuyi said the extra warmth helped covered plants reach the fruiting stage earlier. Relative humidity under the cover did not change, which matters because damp conditions can encourage fungal disease in strawberries. Preliminary tests found no significant difference in soil bacteria around the roots.

The same lab's earlier work with a similar fabric over cabbage increased vegetative growth 2.93-fold, according to the paper's abstract. The strawberry study was designed to answer a question that work left open — whether the cover would also boost fruit, not just leaves. Strawberries were chosen because they grow across three seasons and growers already use single-layer covers to protect flowers and fruit from freezing, the authors wrote in the abstract, which is also summarized on ScienceDaily.

Pesticide and Water Savings Still Unproven

The university said the technology could significantly reduce water and pesticide use. Olawuyi said that by deterring insects, Plant Armor could reduce the need for traditional pesticides.

Readers should note what the study did and did not measure. The paper documents yield, light, temperature, humidity, and aphid exclusion. It does not report measured reductions in pesticide applications or water use in a commercial setting. Those benefits are plausible, since a physical barrier can replace some sprays, but they have not yet been quantified.

The trials were run in tunnels, which differ from open fields in temperature, wind, and pest pressure. The authors write that on-farm testing is now needed to examine the textile on a variety of crops in different geographic locations. Cost is another unknown. A durable knitted fabric may cost more than the thin single-layer row covers many strawberry growers already use to protect flowers from frost, and no price comparison has been published.

There is also a commercial interest to disclose. The Plant Armor Gen 2 fabric studied in the paper is patented by NC State and licensed for commercial development by the university. The work was funded by the North Carolina Agricultural Foundation and the U.S. Department of Agriculture's National Institute of Food and Agriculture.

Next Steps for Growers and Gardeners

For commercial strawberry growers, the practical step now is to watch for on-farm trial results and talk with state extension specialists before changing pest management plans. Growers who already use row covers know the trade-offs with pollination, heat, and handling, and any new cover would need to fit those routines.

Home gardeners can apply the basic idea today with existing insect netting or row covers, which are widely used to keep pests off vegetables. The NC State product is not yet sold as a consumer item based on information released so far.

If on-farm tests confirm the tunnel results, Plant Armor could become one more tool in integrated pest management, which combines physical barriers, monitoring and targeted sprays to reduce chemical use. The bottom line: a knitted fabric more than tripled strawberry yields in controlled tests, but claims about pesticide and water savings remain to be proven in real fields.

What Readers Want to Know

What is Plant Armor?

It is a knitted, three-dimensional fabric developed at NC State that is draped over plants. Its layered structure blocks insects while letting light, rain and air through.

How much did it increase strawberry yields?

Covered plants produced up to 3.56 times more harvestable fruit than uncovered plants in tunnel field tests over three growing seasons.

Why didn't the fabric's shade reduce fruit?

Researchers found it did not reduce light reaching the plants, and covered plants showed no shade-avoidance response. The cover also kept plants warmer.

Does it reduce pesticide use?

Researchers say it could, because it blocks insects physically. The study did not measure actual pesticide or water savings on farms.

Can farmers buy it?

NC State has patented the fabric and licensed it for commercial development. On-farm testing is still needed.

Can home gardeners use something similar?

Gardeners can use existing insect netting or row covers to keep pests off crops, though results will vary by product and plant.