Care of pot plants

Question: care of pot plants

I have several aromatic plants of common use on my balcony, for some time I have seen that they all have small white spots on the leaves, I believe that these are not pests, what are they due to?
Congratulations for the column I always follow with passion. Sincerely

Answer: care of pot plants

Dear Alfredo,
usually the presence of small white spots on the leaves of aromatic plants indicates the presence of insects; these small insects sting the leaf lamina to feed on the lymph contained in the leaf, and their puncture subtract liquid, often leaving a clear sign of their passage, which translates into tiny portions of almost transparent leaf, or white, devoid of chlorophyll. What insects it is difficult to say, not having a photograph of the plant, and not having been able to identify them; it could be leafhoppers or white flies, typically in the case of these insects, when you pass close to the plant or shake some leaves, you notice a rapid flicker of tiny insects. But it could also be mites, also called red spiders, which blatantly bleach the leaves, causing very small dots; if mites are present, you should also notice small spider webs between the leaves, produced by these little animals that are not insects but arachnids. To solve the problem the best method is to cut down all the plants, in order to remove most of the insects and ruined leaves, and therefore you will have to deal with a product to do so in order to eliminate any remaining insects, eggs and larvae. Clear that you will not be able to cut all the plants, also because I don't know what plants they are, but thyme, sage, parsley and basil can easily be pruned quite low, because within a few weeks you will find yourself a nice amount of new vegetation; if you have very old rosemary plants, or even oregano ready to harvest, perhaps you should treat the leaves without pruning. That being said, what product should you use?
Given that these are aromatic plants, which you then cultivate to add to your dishes, it is good to avoid systemic products, that is products that enter the tissues of plants: rather, use insecticide and acaricide products suitable for organic farming, such as those based on pyrethrum natural, or other products popular in hobby stores. It is fundamental that they have a short time shortage, that is the period during which you will not be able to collect the leaves; in products suitable for organic farming, the deficiency time is usually 3-5 days, so your plants will return to being edible before they have produced new leaves after pruning.