Abstract
Diatomaceous earth (DE), a naturally occurring silica-based powder, is increasingly recognised as a sustainable alternative to chemical pesticides in agriculture and horticulture. DE controls insect pests through a physical, non-toxic mechanism, reducing reliance on synthetic chemicals while maintaining crop protection. This report reviews DE’s modes of action, effectiveness, safety, and substitution potential, providing guidance for use as part of integrated pest management (IPM) strategies.

1. Introduction
Chemical pesticides have been essential in modern agriculture and horticulture for controlling insects, fungi, and weeds. However, widespread chemical use raises human health risks, environmental contamination, and the emergence of resistant pests. Natural alternatives like diatomaceous earth provide a mechanical, non-chemical solution that is safe for humans, animals, and the environment, offering a viable pathway to reduce chemical dependency.

2. Diatomaceous Earth as a Natural Pesticide

2.1 Composition and Mode of Action

• DE is composed of fossilised microscopic diatoms with porous silica shells.
• Insects exposed to DE experience abrasion of the exoskeleton, leading to dehydration and death.
• Unlike chemical pesticides, DE’s effect is physical, not toxic, and pests cannot develop chemical resistance.

2.2 Target Pests

• Insect pests: ants, cockroaches, beetles, weevils, mites, aphids
• Storage pests: grain weevils, flour beetles
• Garden pests: slugs, earwigs, soft-bodied insects

2.3 Application Methods

• Soil and crop dusting: Applied to soil or foliage to prevent insect damage
• Stored produce protection: Sprinkled on grains, legumes, or other stored crops
• Animal husbandry: Used in poultry bedding and livestock areas to control mites and lice

3. Effectiveness Compared to Chemical Pesticides

Aspect	Diatomaceous Earth	Chemical Pesticides
Mechanism	Physical, abrasive	Chemical, neurotoxic or systemic
Target Specificity	Broad, affects many insects	Often species-specific, but can harm non-target organisms
Residual Activity	Moderate, persists if dry	Can degrade over time; often requires repeated application
Resistance Development	Very low	High; pests can develop resistance
Human Safety	Low toxicity	Higher; potential acute and chronic risks
Environmental Impact	Biodegradable, minimal contamination	Soil and water contamination; biodiversity loss

Summary: DE is highly effective against many pest species and can substitute chemical pesticides in various settings, especially for organic and low-chemical farming.

4. Human and Environmental Safety

• Food-grade DE is considered safe for humans and animals
• Inhalation of fine DE dust may cause respiratory irritation; use PPE during application
• DE does not leave chemical residues in crops, soil, or water, making it environmentally sustainable
• Minimal impact on beneficial insects if applied carefully

5. Advantages of Using DE as a Substitute

• Reduces chemical dependence: Safer alternative for growers seeking organic or low-toxicity pest management
• Non-toxic and biodegradable: Low health risks for applicators and consumers
• Resistance-proof: Effective against pests resistant to chemical insecticides
• Environmentally friendly: Minimal soil and water contamination
• Cost-effective: Requires fewer resources in terms of safety measures and regulatory compliance compared to synthetic chemicals

6. Limitations and Considerations

• Moisture sensitivity: DE loses effectiveness in high-humidity or wet conditions
• Slow action: Results are gradual; pests die over several days
• Coverage requirement: Thorough application is essential for success
• Limited spectrum: Not effective against all pest species; may need combination with other IPM strategies

7. Practical Recommendations for Substitution

• Integrated Pest Management: Combine DE with crop rotation, biological controls, and selective chemical use for comprehensive pest control
• Application Guidelines: Apply thin, even layers to foliage, soil, or bedding; avoid wet conditions
• Safety Measures: Wear masks and gloves to reduce inhalation; provide clear user instructions on product label
• Targeted Substitution: Use DE for pests in food crops, stored produce, vegetable gardens, orchards, and poultry areas to reduce chemical use

8. Conclusion
Diatomaceous earth offers a safe, effective, and sustainable alternative to chemical pesticides in agriculture and horticulture. While slower acting and moisture-sensitive, DE’s physical mechanism, low toxicity, environmental safety, and resistance-proof properties make it an excellent substitute or complementary measure to reduce chemical reliance. Proper application, adherence to safety measures, and integration into IPM programs can optimise its effectiveness while supporting human health and ecological protection.

References

• Fields, P. G., & Korunic, Z. (2000). Residual effects of diatomaceous earths on stored grain insects. Journal of Stored Products Research, 36(3-4), 193–202
• Subramanyam, B., & Roesli, R. (2000). Inert dusts. In: Subramanyam, B., & Hagstrum, D.W. (Eds.), Alternatives to Pesticides in Stored-Product IPM. Springer
• Korunic, Z. (1998). Diatomaceous earths, a group of natural insecticides. Journal of Stored Products Research, 34(2-3), 87–97
• Ebeling, W. (1971). Insect Control with Silica Gels. Annual Review of Entomology, 16, 123–158
• APVMA (2025). Exempt Active Constituents. Australian Pesticides and Veterinary Medicines Authority. https://apvma.gov.au

Contact AusDE

For sample requests or supply inquiries, contact AusDE at [email protected] or call +61 2 9251 7177.

Experience the journey of diatomaceous earth (diatomite / DE) from the lakebed at Badgingarra to your end product — naturally Australian, naturally occurring, and fully adaptable to your innovation.