The shortcomings of using Mesh vs. Hole Size to select an insect screen:
Mesh is a term to describe woven products that indicates the number of yarns per unit measure. So mesh can mean yarns per inch or yarns per centimeter, depending upon the location of origin.
Insects are denied passage based on the ability to fit their largest section through the hole in the weave. If the yarn diameter and mesh are not known, it is not possible to determine hole size.
*It is best to select screens based on hole size and not mesh, since mesh alone cannot indicate a screens ability to exclude the insect of interest.
Anywhere insects may come in the greenhouse, including: sidewalls, roof vents, doors.
- Seal unscreened points of entry.
- Double air lock entry for personnel.
- Consider pressure losses for each crossing.
ECONET Tips for Excluding Insects
- ECONET generally must have openings as small or smaller than the insects it excludes.
- Any ECONET will reduce the number of insects migrating into crops.
- ECONET must be sized appropriately to avoid hampering ventilation.
- Keep doors closed, except when entering or leaving the greenhouse. Train employees on function, use & importance. Consider clean paths for tools, carts. etc.
- Create a positive pressure entrance by installing fans so that they blow into the space between the doors causing air to flow from inside to outside.
- ECONET must be cleaned periodically. Use a stream of water to wash from inside to out.
- Insect screens will shrink about 3% of the length in both directions.
Therefore, install them without tension and they will tighten over time.