mealy bug control

Rodger Whitlock
Thu, 08 Dec 2011 22:12:49 PST
On 8 Dec 2011, at 16:49, Robert Hoel wrote:

> The concept behind diatomaceous earth is that the very fine particles are like
> glass shard and the critters that crawl through it have there little bodies
> sliced to shreds.

Wherever you read that, it is an exaggeration and a misunderstanding of the 
mechanism by which diatomaceous earth kills insects.

In the simplest analysis, insect exoskeletons are composed of chitin with a 
waxy layer on the outside to prevent water loss. Diatomaceous earth abrades the 
waxy layer leading to uncontrolled desiccation and death of the insect.

A far cry of being sliced to shreds, though both lead to death.

PS: Digging into Wikipedia, I find a link to…

which asserts that diatomaceous earth _absorbs_ the waxy layer, as opposed to 
_abrading_ it. I do not know which explanation is correct.

Rodger Whitlock
Victoria, British Columbia, Canada

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