Diatomaceous earth

How it works

Microscopic fossil shells with razor edges abrade the waxy cuticle of crawling insects so they dehydrate. Entirely physical.

Recipe

Dust a thin visible film on dry soil or leaves, or on the route pests walk.

How to apply

Apply to dry surfaces on a dry forecast. Reapply after every dew or shower.

Targets — pests

Ants, Flea beetle, Earwigs, Crawling insects

Targets — diseases

Not recorded — the field is blank rather than guessed.

Supplies: Diatomaceous earth, Gloves and mask

Days to harvest after spraying: 1

Best months: not recorded

Cautions

Completely useless once damp - and it does not distinguish friend from foe, so it kills ground beetles and can harm bees if dusted on flowers. Wear a mask: the dust irritates lungs.

The thing people get wrong

Never dust it on or near open flowers. It is often sold as harmless because it is a mineral, but a bee that walks through it dies the same way an ant does. Keep it on the ground, in a targeted line, and only where a specific crawling pest is coming from.