How safe are natural insecticides?

'All-natural' doesn't mean non-toxic. Dr Joanna Dowle (Senior Advisor at the Environmental Protection Authority) looks at four plant-based insecticides to bust the myth that 'natural' chemicals are safer than those made in a lab.

This is an excerpt from the EPA’s Science at work series of science communication stories.

Chemicals are chemicals, whether they come from a plant or a lab. Plants have evolved over many thousands of years to make their own pesticides specific to the critters that like to nibble on them. 

Inspired by these complex processes and products of plant self-defence, natural product chemists have developed ways to extract these chemicals from plants and figure out what they are. 

Synthetic chemists have then developed ways to make these chemicals – and related synthetic derivatives – in the lab.

Whether lab-made or direct from nature, if two molecules have the same chemical structure, they will have the same properties – regardless of whether one was made by a series of enzymes in the cell of a plant, or by a chemist in flasks in a lab.

But the myth persists that chemicals made by plants are somehow safer than chemicals made by people. The buzz words “all-natural” and “organic” are all too frequently used to convey a message that something is safe. 

The facts about natural insecticides

Let’s have a look at a couple of plant-based insecticides.

Neem oil

Here are the details about neem oil and its use as a natural insecticide:

Pyrethrin insecticides

Here are the details about pyrethrin and its use as a natural insecticide:

Continue reading the story: How safe are natural insecticides? | EPA