Material Physicality
Insect Exclusion Screens
If it is feasible, we recommend an “open-system.” An open system allows insects to come and go as they please. This may seem careless. However, most insects are beneficial to growers, not pestiferous. In some cases, though, an open system is simply not possible. For example: a neighboring agricultural operation may negatively affect your own, or your location or crop may invite an unusual number of pests.
When a “closed system” is deemed necessary, screens will make it possible. Before choosing a screen, several factors should be considered, though: sizes available; basic construction; shading value; mesh opening sizes [exclusion ability]; cost; ventilation/cooling reduction; UV stability guarantee; ease of installation; etc.
There are two typical screen types available, of which one may meet your criteria: Anti-Virus screen or No Thrips screen. Both are made of transparent, easy to clean, high tensile-strength round polyethylene monofilament. The typical specifications for these screens is as follows (based on Green-Tek screens):
“Anti-Virus” Insect Screen
- Sizes Available
- Standard widths 43", 78", 118", 137", and custom widths of 59" and 94" available. Cut to desired length. Maximum length 656'.
- Basic Construction
- 50 x 24 ct. mesh; 1/1 weave with a 0.24mm. thread size; 0.037 lbs./yd2. The open area is 50%.
- Shading Value
- 20%
- Light Transmission
- 80%
- Mesh opening sizes
- 0.0105"x0.0322", excludes aphids, leafminers, whiteflies, 80% of western flower thrips, and more.
We can order this for you — please contact us.
“No Thrips” Insect Screen
- Sizes Available
- Standard widths 39", 78", custom widths available. Cut to desired length. Maximum length 328'.
- Basic Construction
- 81 x 81 ct. mesh; 1/1 weave with a 0.15mm. thread size; 0.024 lbs./yd2. The open area is 25%.
- Shading Value
- 33.3%
- Light Transmission
- 66.6%
- Mesh opening sizes
- 0.0059"x0.0059", excludes all insects mentioned above plus 100% of western flower thrips, and more.
We can order this for you — please contact us.
Either screen type will reduce the influx of pests, reduce the occurrence of diseases transmitted by pests, and keep biological pest control agents in the greenhouse with the crop.
Floating Row Covers
In general, floating row covers serve a multitude of purposes in addition to keeping pests away from plants. Some of their attributes are as follows:
- They protect tender, young crops from cold weather, frosts and wind; they retain heat, moisture and humidity, and act as season extenders. Please note the heat retention can be a disadvantage in the summer months. However, for many crops, row covers should be removed in the summer months, anyway, to allow for proper pollination and fruit set.
- They allow filtered sunlight, air and water to reach the crops.
- By keeping plant pests at bay, disease transmission is reduced.
- They will effectively keep many biological pest control agents in with the crop.
- Row covers are lightweight, strong, cost-effective and very easy to use. They don’t normally harm plants or stunt their growth (though some abrasion damage can occur in very windy areas) — they actually promote fuller growth.
- Their use doesn’t significantly add to labor costs.
Sorry, product is no longer available.
Copper Slug and Snail Barrier Tape
Copper barrier tape is an extremely effective way to keep slugs and snails from getting at your plants. Slugs and snails excrete a slime, upon which they transport themselves.
Thanks in part to this slime, and the copper strip, when slugs and snails come into contact with it an electrochemical reaction occurs and the copper emits a small, electrical charge. The electrical charge is enough to effectively repel these pestiferous mollusks. Think electric fence.
This product is 100% percent effective against slugs and snails — they simply cannot cross this copper barrier if it lies vertically in their path — provided the copper stays clean enough.
Copper barrier tape comes on a roll like normal tapes. It is useful on trees, raised beds, greenhouse bench legs, and anyplace slugs and snails are a problem. It may also be attached to a 2" x 4" piece of lumber and flexible edging and placed anywhere as a semipermanent barrier.
Sorry, product is no longer available.
Expanded Copper Mesh Strips
Also made of copper are mesh strips. They appear to be expanded strips of copper — the same way an expanded metal bench top is made — creating a sort of loose matrix or web of copper filaments (we may be inaccurate with our analogy but if we’re in the ballpark you get the idea). According to the manufacturer this effectively creates a physical and electrochemical barrier. By comparison the above-described tape creates only an electrochemical barrier.
As of this time, we’re not sure about these claims for a few reasons and ask that you try them out for yourself and let us know. According to one report these strips are 97% effective so chances are you’ll have decent success if you use them correctly: wrap the plant’s stem two or more times, 1-2″ above the ground, to create a snug (but expandable) fit with the mesh strip, then twist the ends together to keep it in place. Like the tape this should be done on plants that have a main stem but whose leaves don’t touch the ground (creating shortcuts). These strips should probably be changed annually as cleaning will not be possible.
You may purchase Expanded Copper Mesh Strips online now!
For more on slug and snail control, do check out our incredibly effective iron phosphate bait.
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