How the intervals are worked out
The pre-harvest interval (PHI) is the minimum number of days between the last application of a product and the harvest. The restricted-entry interval (REI) is the time during which nobody may work in the treated block without protection.
Each product in the tank carries its own figures. The calculator takes the longest PHI and adds it in days to the date the application finished, and adds the longest REI in hours (or days) to the finishing time. It also names the product that sets each limit, so you know which one to swap if the date does not suit you.
Example
A tank with a fungicide (PHI 21 days, REI 12 h) and an insecticide (PHI 14 days, REI 24 h) finishes at 18:00 on 2 August. The fungicide sets the PHI: harvest is allowed from 23 August. The insecticide sets the REI: the crew can go back in from 18:00 on 3 August.
Frequently asked questions
What is the difference between PHI and REI?
The PHI protects the consumer: it gives residues time to fall below the legal limit before the grapes are picked. The REI protects the people working in the vineyard: it keeps them out while contact with the fresh deposit is a risk.
Which interval applies when I mix several products?
The longest of each. One product can set the PHI and a different one the REI.
Does the PHI count from the start or the end of the application?
From the end of the application on that block. If spraying a block took two days, count from the last day.
What if the label gives no REI?
Keep people out at least until the spray has dried on the canopy, and follow any protective equipment the label asks for during re-entry.