Chelated Iron Phosphate Application in Slug Control
Iron phosphate is a natural mineral substance. The associated chelate is a synthetic acid amino acid. Commercial specialties are offered in the form of granular baits based on flour.
Chelated iron phosphate can be found on the market in the commercial solutions listed here.
How does it work?
Iron phosphate is a natural substance with almost no environmental impact and is found almost everywhere. Its toxicity is indeed very low with an oral LD50 in rats of 1487 mg/kg in males and over 5000 mg/kg in females. For reference, the LD50 of table salt is 2000 mg/kg. This toxicity is so low that ferric phosphate alone would not have molluscicidal efficacy. It is therefore chelated, which allows it to accumulate in the digestive system of slugs before releasing the iron that acts by intoxication. The mollusks then stop feeding and quietly die in the soil. Counting dead slugs is therefore a poor indicator.
As with all slug control products, the challenge of bait formulations is to ensure good rain resistance, and a high number of granules at the same approved dose, because a touched granule becomes less attractive. SLUXX is used in the same way as methaldehyde-based granules.
Benefits
- The least ecotoxic of slug control products
- Up to 66 granules/m² at 7 kg/ha compared to 54 for the best methaldehydes.
- Formulation fairly resistant to rain
- Like all biocontrol products, counts as 0 IFT.
Limitations
- Not completely free of toxicity to earthworms (anecic).
- The chelate, considered as a formulation agent, is not subject to the same registration rules as active substances, although it explains the low but not zero ecotoxicity of the commercial product and ensures its efficacy.
Advisor's opinion
Ferric phosphate should be integrated into a broader crop system approach.
- For crops in autumn, the most effective is to disrupt the slug cycle during the summer intercrop period (especially soil tillage), particularly when climatic conditions are already difficult for slugs (numerous predators, drought, low food resources).
- For spring crops, choose intercrop Cover crops that are unpalatable such as mustard or phacelia. Promote numerous predators such as birds, reptiles, amphibians, small mammals, nematodes, fungi, but especially ground beetles which are the main predators of slugs at night.
- Care for sowing to promote rapid crop development.
- Fight in a reasoned way. Setting traps beyond the threshold allows detecting the presence of the pest and anticipating damage. One can be at the threshold and have damage, or beyond the threshold and not have any because it is dry outside the protection and moisture offered by the traps.
- As a last resort, ferric phosphate is nevertheless the most respectful solution for beneficials and earthworms.
Due to the toxicity of the chelate, pay attention to good practices by not leaving piles accessible to domestic and wild animals or children.
Cost
€30/ha
Sources
- This article was written based on the document The fields of possibility in biological control on large crops jointly written by François DUMOULIN, Hélène BAUDET, Gilles SALITOT and Inma TINOCO from the Chamber of Agriculture of Oise.
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