Is there a difference between a “systemic” insect control insecticide spray vs. a foliage (or, foliar) insecticide spray? Wild guess: Is a systemic for broader use than a foliar? If this is true, can a systemic be used as a foliar?
A systemic is supposed to act throughout the plant’s system so you don’t have to spray every leaf you want to kill. In practice for tough plants like poison ivy I found you still have to spray almost every leaf.
Yes. Foliar insecticides are what we think of as “normal” insecticides. You spray them on, and they kill the bugs on the leaves, and in many cases leave a residue that kills future bugs that walk on it or eat it. They are decomposed by rain/watering and sunlight.
Systemic insecticides, like the infamous imidacloprid, are ones that you can literally pour on the roots, and it’ll be absorbed and distributed throughout the plant, killing bugs that eat any part of it, regardless of where it was poured/sprayed, and whether it subsequently rains on the plant, is sunny, etc…
One big issue with systemics is that they tend to get into ALL parts of the plant, even pollen. So insects like bees get sub-lethal doses when gathering pollen from treated plants, and it causes them all sorts of problems. Another is that they’re in the soil and somewhat less directed than sprayed insecticide, so they have a lot of collateral damage sometimes.
Thanks all for the replies. I did not know there are two types out there, and these terms are well hidden or non-existent on most/many products. So, it seems the two types of sprays are NOT interchangeable, true? I wager a systemic treatment will be useless if applied as a foliar spray.
Footnote: I was using “Systemic Insect Control” by Bonide. The name implies one would use systemically through the roots. Yet the instructions say to cover the foliage, Now, I am really confused. I wager the product name is misleading.
As I recall, the garden center clerk told be to spray the ground near my infested trees (with bagworms). OTOH, my infestation has been so bad, I will have to use a foliar spray, as well, to keep this year’s anticipated attack manageable.
Most/many plants will absorb through the leaves as well as through the roots. It’s common to apply systemic herbicides and systemic fertilizers by foliar spray. Absorption from the leaf into the root will depend on the time of year and whatever, but if you are targeting leaf insects, foliar spray might (FAIK) be faster and more effective than ground application.
Melbourne, thanks! That’s good to know!