The powder that keeps caterpillars off the roses works by shutting down an insect's nervous system and that mechanism isn't as selective as the label might suggest.
What It Actually Is
Carbaryl is a carbamate insecticide used widely on home lawns, vegetable gardens and ornamental plants to control a broad range of pests, from caterpillars to grubs to fleas.
Why It's On The List
The EPA considers carbaryl likely to be carcinogenic in humans based on increased tumours in animal studies, and it works by inhibiting cholinesterase, an enzyme essential to nervous system function, in insects and mammals alike. The agency has specifically flagged residential lawn and garden uses as carrying risks of concern for neurotoxicity, distinct from dietary exposure through food, which it considers low-risk.
Where It Hides
Garden dust and spray insecticides for vegetables, roses and lawns, some flea powders, and turf treatments for grubs.
At Bunnings, Carbaryl is the active ingredient in David Grays 250ml Carbaryl Garden Insecticide and Richgro 250ml Caterpillar Grasshopper and Millipede Killer.
The Kura Take
This is one where the EPA's own risk assessment does a lot of the talking; residential use is flagged even though dietary exposure isn't and we dont recommend using it. We beleieve it causes harm to the environment and to us.
What To Use Instead
Row covers, companion planting, and targeted least-toxic options like insecticidal soap or Bacillus thuringiensis (Bt) for caterpillars, or diatomaceous earth for crawling pests.
This article is for educational purposes only and does not constitute medical advice. Always consult a qualified health professional before making changes to your health or home care routine.
Sources: Carbaryl Hazard Summary, US EPA (https://www.epa.gov/sites/default/files/2016-09/documents/carbaryl.pdf); EPA Proposes Improved Mitigation for Insecticide Carbaryl, US EPA (https://www.epa.gov/pesticides/epa-proposes-improved-mitigation-insecticide-carbaryl-including-pilot-protecting)