Why Insect Netting Is Woven, Not Knitted
How physical exclusion helps protect crops from fruit fly and other insect pests
Knowledge Centre | Shade & Crop Protection
For insect exclusion, aperture consistency matters
The Question
Why does the construction of insect mesh matter?
Insect netting may look like a simple piece of mesh. But when its job is to stop insects such as fruit fly from reaching a crop, the construction of that mesh becomes extremely important.
Many agricultural nets are knitted, giving them flexibility and the ability to stretch. Insect exclusion mesh is typically designed around a more dimensionally stable woven structure. The reason is simple: when you are trying to exclude a small insect, maintaining a consistent opening size matters.
Woven vs Knitted: Why the Structure Matters
A knitted net is made from interconnected loops. That structure can provide useful flexibility and stretch for products such as bird netting and many shade fabrics.
A woven insect mesh is constructed with yarns crossing in two directions - warp and weft. This creates a comparatively stable grid with much less extension under normal installation tension.
The important advantage is not simply that woven mesh feelsfirmer. It is that the openings are designed to remain moreconsistent when the fabric is installed and tensioned.
For insect exclusion, this is critical. A nominally small opening is of limited value if the mesh can distort enough to create substantially larger gaps.
Look Closely at the Structure
The Problem
Fruit Fly Does Not Need to Eat the Crop
Queensland fruit fly is an important horticultural pest in eastern Australia. Female flies can lay eggsinside susceptible fruit and vegetables; larvae then develop inside the produce, causing damage and making fruit unmarketable.
This is why fruit fly management is not only about killing insects after pressure develops. A powerful alternative is to prevent the insect from reaching the crop in the first place.
Agriculture Victoria describes insect-proof netting as the best way to prevent female Queensland fruit fly from laying eggs inside fruit and vegetables, provided the net is fine, secure and used correctly after pollination.
Source: Agriculture Victoria - Controlling Queensland fruit fly in home gardens.
Exclusion Rather Than Treatment
A Physical Barrier Before Damage Occurs
Insect netting works by changing access to the crop. It does not kill the pest; it creates a physical barrier between the pest and the plant.
Insect netting doesn't kill the pest. It changes whether the pest can reach the crop.
When properly selected, installed and maintained, exclusion mesh can support Integrated Pest Management (IPM) and reduce reliance on insecticide applications. Research on greenhouse screens also recognises that physical exclusion can reduce insect migration, direct crop damage and insect-transmitted disease pressure, thereby reducing the need for pesticide application.
Sources: Agriculture Victoria; Agricultural and Forest Meteorology research on insect-proof greenhouse screens.
Mesh Size Matters - But Smaller Is Not Always Better
The opening must be small enough to exclude the target pest. But making the opening smaller introduces another engineering challenge: air still needs to move through the protected structure.
Fine-mesh screens create resistance to airflow. Studies of screened greenhouse openings show thatlower-porosity screens can reduce natural ventilation and may increase internal temperature and humidity.
The goal is not to use the smallest mesh possible. The goal is to use the right mesh for the target pest while maintaining as much ventilation as practical.
Airflow performance depends on more than the nominal hole size. Porosity, yarn diameter, yarn geometry and the overall screen structure all influence pressure drop and ventilation
Protection, Airflow and Light
A good insect mesh must balance several functions at the same time. Its primary purpose is pest exclusion, but the finished structure also influences airflow and light transmission.
Depending on mesh density, yarn diameter and colour, the net can provide a modest shading effectwhile still allowing substantial light and air movement. The objective is not to create a sealed greenhouse, but a protected growing environment.
Pest exclusion - keep the target insect outside.
Airflow - retain sufficient ventilation for the crop and structure.
Light - avoid unnecessary loss of useful crop light.
Dimensional stability - keep apertures consistent after installation
Common Misconception
"The finer the mesh, the better the insect net."
Not necessarily. A finer opening may exclude smaller insects, but it can also create greater resistance to airflow. Different crops and structures have different requirements for ventilation, temperature, pollination and pest control.
The best mesh is therefore not automatically the finest one. It is the mesh that achieves the required exclusion without unnecessarily compromising the growing environment.
What About Pollination?
If a mesh can keep pest insects out, it may also restrict access for beneficial pollinators. For flowering crops that depend on insect pollination, growers need to consider installation timing or the use of managed pollinators inside the protected area.
Agriculture Victoria recommends applying insect-proof netting after most flowers have been pollinated for continuously flowering crops such as tomatoes, eggplants and capsicums.
Source: Agriculture Victoria - Protect your summer tomato harvest.
Insect Net, Insect Mesh or Quarantine Mesh?
The terms are sometimes used commercially for similar fine-mesh products, but they should not automatically be treated as identical specifications.
Insect netting or insect mesh describes the general physical-exclusion function. 'Quarantine mesh' is often used commercially for fine, dimensionally stable mesh intended for higher-exclusion or biosecurity-related applications.
Where formal quarantine or phytosanitary compliance is required, the actual aperture and the relevant regulatory specification should always be checked rather than relying on the product name alone.
Frequently Asked Questions
Is insect netting the same as shade cloth?
No. Shade cloth is designed primarily to manage solar radiation. Insect netting is designed primarilyto create a physical barrier against a target pest. Any shading effect is secondary.
Why use woven mesh instead of knitted netting?
Woven construction provides greater dimensional stability and helps maintain more consistent apertures. This is especially important when exclusion depends on preventing an insect of a particular size from passing through the mesh.
Can insect netting reduce pesticide use?
Yes. Physical exclusion can reduce reliance on insecticides as part of an IPM strategy. It does not eliminate every pest or disease problem, so crop monitoring and other controls may still be required.
Does insect netting reduce airflow?
Yes, to some degree. All fine mesh creates resistance to airflow. The extent depends on aperture, porosity, yarn diameter, geometry, installation and structure design.
Aus Crop Cover Insight
The Right Barrier, Not Simply the Smallest Hole
When selecting insect netting, it is easy to focus only on the size of the openings. But effective cropprotection involves more than aperture alone.
Mesh stability determines whether those openings remain consistent. Mesh size determines which insects can be excluded. Mesh porosity and yarn geometry influence how easily the protected environment can breathe.
A well-designed insect net therefore needs to balance exclusion and growing conditions, rather than maximising one at the expense of the other.
The goal isn't to create the smallest opening. It's to create the right barrier.
Key Selection Questions:
Which insect are we trying to exclude?
What aperture is required for that target pest?
How stable is the mesh when installed and tensioned?
How much airflow does the crop and structure require?
What effect will the mesh have on light and shading?
Does the crop require insect pollination?
Is there a formal quarantine or biosecurity specification that must be met?
Technical Reference Notes
Agriculture Victoria: insect-proof netting is recommended as a physical exclusion method for Queensland fruit fly; secure installation and pollination timing are important.
Greenhouse-screen research: fine insect screens reduce insect entry but can also reduce ventilation and light transmission; screen porosity, yarn geometry and fibre diameter affect airflow resistance.
Knowledge Centre principle: choose mesh according to the target pest and growing environment, not by mesh fineness alone.
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