Insecticides, what's fit for purpose?

Intro - Types (Organic,  Convensional) - What to Use - Safe Use


Insecticides are extremely popular, probably more so than weed killers, however very few people understand how they work or the dangers they can pose when missused. When you buy or use a pesticide, there are two things you should keep in mind:

Most insecticides are poisons. They are designed to be safe for use by humans but they are still poisons.

When used correctly, insecticides have a minimal effect on the environment. When used poorly they can be damageing to bees and others.

This is true for both Convensional AND Organic pesticides.

With this in mind, so long as insecticides are used carefully they can be useful without being destructive.


Types of Chemical

There are two main types of retail pesticide, Contact and Systemic and each have their benifits and problems.


Most of the time systemic chemicals are the insecticide of choice, the majority of them are currently neonicitonoids that provide protection for about 6 weeks, they are useable on certain edible plants (check the back of the bottle) and they don't need to be sprayed directly onto the plant. Recently there has been a massive backlash against them as they potentially could harm bees. There are new systemic chemicals in development but these are still a year or two away. There are no organic systemic treatments.

Advantages vs Contact Disadvantages vs Contact
Easyer to apply on tall out of reach plants Potentially dangerous to necter useing insects
Protects plant for up to 6 weeks Have a limited number of uses per crop
Don't need to directly hit pest Often has an harvesting interval
Kills almost any sap sucking pest  

Systemic Drench

The only drench (pour on) pesticides available right now are targeted at vine weavel. It is effectively a very highly concentrated version of the same pest killer used for insect control. It works well on vine weavel larvae which are generally quite resistant and it is the only chemical method of control. That said it is extreamly potent and should be only used responsably and with care.



All contact insecticides, regardless of if they are organic or conventional have one important limit. They need to hit the pest to do anything. This means they are limited slightly in use, where you are trying to treat a hard to hit pest, such as on


Safe Use:

Chemicals made from concentrate should not be kept more than 8 hours as they degrade over time and become potentially useless or dangerous to the plant.

Chemicals should only be made to the strength listed on the packaging, if they are made stronger then they can be dangerous to you and the plant.

Sprays should ideally be used in the early morning or late evening as they are less likely to damage the plant and less likely to hit benificial insects.

Do not apply in a sprayer in windy weather to avoid blowback.