It is basically a plant nutrient with strong fungicidal activity that is applied to a wide range of crops hosting the pests. 

Use of a wetter/spreader such as Natural Wet enhances its efficacy.  

RATE AND METHOD OF APPLICATION: The recommended rate of use is 5mls/lit of water for Blights and 3mls/lit for other diseases.
Lower rates (2mls/lit) are known to perform well under moderate and low infestations.
It is applied as foliar spray, drench, root dip or on soil broadcast.
The rate of use for in drip is 2mls/lit of water applied last in the day. Spray to wet and repeat every 28 days until the symptoms disappear.  

TIMING OF APPLICATION: Apply at first instance of infestation and repeat every 28 days.
For drenching/root dipping in crops such as pineapples and avocadoes, first apply at planting and then repeat every 3 months.

CONTRADICTIONS: Fosphite may be applied in mix with other pesticides and fertilizers except for Copper and Copper compounds. But always test compatibility with a small quantity before mixing. PRECAUTION: Avoid careless contacts with the skin or ingestion. 

STORAGE: Store in a cool dry place in the original container. Preharvest Interval: It is recommend to harvest the day after application.