Many pesticides only have full effect at a key stage in the life of the pest and/or crop. For example, when:
- the weed is at an early growth stage; or when
- the level of disease or the number of insects is low.
You will need to consult your pesticide label to find if there are any key stages to be aware of. If there are, you will need to estimate the dates when your crop and pest will be at that key stage and ready to spray. You will also need to read your pesticide label to find out if there is:
- a witholding period (when the treated area may not be entered), and/or
- a harvest interval during which the crop may not be harvested.
These may restrict your 'spraying window' by limiting the dates between which you can spray.