I reckon spraying, while it may have a place in gardening, is a last resort. It treats the symptom, not the cause. If something is devouring
plants, there is an imbalance and unfortunately sprays are generally not species specific. In the case of sap sucking bugs like aphids, there are many predators that feed on them, like preying mantis and lady beetles. Also some birds will eat them.
Even if you kill them all, the ants may bring them back again so you will have to repeat the treatment indefinitely. If you feed your
plants with an organic fertiliser, such as compost with added sulphate of potassium, it will toughten the leaves and they will no longer be palatable to the insect pests. Just a further option to consider.
The
plant invigorator you mention Pesticus , is very interesting though. It says in the MSDS that the active ingredient is Urea, which is basically nitrogen. Very interesting methinks.Thanks for the tip.