Phosphine and ways of use
The Phosphine is generated through the following products:
- Tablets / Tablets (Phostoxin®, Magtoxin®)
- Mangas / Mini-Rope®
- Degesch® Plates and Degesch® Strips
This is a sensitive subject due to the tendency in the grain business, worldwide, to reduce costs in all its operations (sowing, harvest, transportation, etc.).
The fumigation is part of these operations and has, recently, suffered cost reductions that have generated an increase of cases where some insects have become resistant due to low dosage treatments.
In the case of Phosphine, the dosage can vary between 1 and 5 tablets per metric ton (1 to 5 grams of Phosphine) for Standard treatments. In the case of the J-System (recirculation), the dosage is pre-established.
The ideal dosage needs to be calculated according to the space in need of fumigation and not according to weight, since we’re working with a gas that should distribute itself homogeneously throughout the fumigated space. The FAO (Food and Agriculture Organization) has established a dosage we consider ideal (45 tablets every 1000 cubic feet of hold space).
The exposure time will depend on the applied dosage and the temperature of the fumigated cargo. The higher the temperature, the lower time required. However, there’s a minimum exposure time needed to eliminate insects that varies according to the species and their evolutive stage.
Adult insects are more sensitive, but there are some species that, during their evolutive stages, are very resistant to fumigation, and eliminating them can take up to 5 days of exposure to phosphine.
Generally, vessels have a 10 day in-transit time, which is enough for a good fumigation to take place. In the case of shorter trips, it’s advisable to use the recirculation system which distributes the gas in a few hours, allowing for a higher exposure period.