Handling and storage
The water-sensitive papers are laid out on artificial supports or stapled directly onto the leaves shortly before spraying takes place. Following exposure to the spray, the water-sensitive paper will be stained dark blue by aqueous droplets impinging on its coated surface. The stained papers must be retrieved as soon as possible and attention should be paid to the following points:
- Gloves should be used (polyethylene or rubber) for handling the papers to avoid staining and contaminating the water-sensitive papers.
- The water-sensitive paper support (natural or artificial) must be dry: the water-sensitive papers should not be laid out in the field while the plants are still wet from morning dew or rain.
- The surface of the water-sensitive paper must not be scratched before use (papers may rub against each other).
- For better visibility of stains from WP or FW applications, the residual dry powder on top of the stains can easily be wiped off with dry paper tissues.
Storage and conservation
Shelflife: Water-sensitive paper packed in its original high-quality sealed alubags can be stored for 10 years and more, provided the sealing remains undamaged. Water-sensitive papers must be stored before and after spray exposure under dry conditions in airtight bags or boxes. Exposed water-sensitive papers can also be protected with a colorless, thin adhesive foil. Avoid air pockets when applying the foil. Aerosol sprays of colorless, synthetic resin can also be used. The pH value of the resin must be in the range of 4.5 to 6.0. Observe instructions for use when spraying with an aerosol can.