Whether you are just starting with gardening or have already been a gardener for many years I am sure you have come across the term systemic insecticide, because it is quite commonly used to describe insecticide, so it is important to understand what it means.
Insecticides usually are classified in two groups, first being contact insecticides that have no residual activity and the second being systemic insecticides that have residual or long term activity. Here it is again the word systemic and this time combined with the word long term.
So what it all means?
The easiest way how to explain what systemic insecticide does is to understand how it works. If contact insecticides kill the insects upon their contact with the plant that is sprayed with this insecticide, hence the name contact insecticide, then systemic insecticide works a bit slower but also very efficient – the systemic insecticide becomes incorporated throughout the whole plant usually in a protein form that is not toxic to humans or animals and then when the targeted insect feeds on this plant, they ingest the insecticide and die. And if contact insecticide will wear off with the wind or rain, because it sits on top of the plants, then systemic insecticide will stay in the plant and will work for quite some time.
The plants are able to absorb the systemic insecticide into their cells and move it around thanks to the fact that this insecticide consists of substances that are highly soluble in water, so that plants can soak up the insecticide just like they would do with water. The downside is that if you apply the insecticide just moments before it starts to rain, there is a good chance that the insecticide will be washed away by the rain because it is water like or if the insecticide is applied incorrectly it can flow down from the plant and into the ground, however if there is no rain and the insecticide is applied correctly then the insecticide will be easily absorbed by plants.
There are some systemic insecticides that are applied to the soil not the plants, however, I wouldn’t recommend them because by doing it this way there is a bigger chance that not only your target insects will ingest this insecticide and be killed but it will be ingested by beneficial insects and even birds that can harm them.
Usually that how efficient each of these insecticides are is determined from that how the insecticide is sprayed. For example if a fogger is used in the application then the results will be much better, because the insecticide droplets will be very small and will thoroughly cover targeted area, but if a sprayer is used that distributes the solution in large droplets, then all targeted plants might not be coated with the insecticide you are using.
Systemic insecticide is one type of insecticide that you should really consider especially if you need to target places that are near other objects that cannot be laced with this insecticide, for example, if you want to spray the flowers that are near the pool with an insecticide, you cannot use contact insecticide, because that can contaminate the pool, however by using systemic insecticide it will be safe to enjoy your pool without having to worry about insects pursuing your flowers.