Roses on the terrace

Question: What are those dots on the foliage?

Hi all, several months ago I bought a plant of roses for my baby, together we took care of it: we put it in a larger vase outside on the balcony and watered every 2 3 days. For some days the leaves have turned yellow and are falling. I do not know if it is the fault of some parasite because at the same time also at the dahlia, at the dimorphoteca and at the basil strange spots have appeared on the leaves that then dry up. What can I do? I am anxious about my plants, I am waiting for your advice. Thanks

Roses on the terrace: Answer: rose pests

Dear Giusy,
unfortunately many varieties of rose are particularly sensitive to a long list of parasites, both fungal and animal; in fact, however, if the problem also occurs on all the other plants on the terrace, we can somehow limit the number of parasites, as not all the typical diseases of roses also affect dahlias and basil. The simplest thing I can think of is the red spider mite: they are tiny size mites, which like sunny positions and a dry climate; in essence it is one of the most widespread pests in summer, especially among potted plants and on terraces, where the summer heat and the sun make the climate decidedly dry, and ventilation is not always optimal. It is not an insect, but an arachnid, in fact red spider is a name that tends to make some confusion, because these arachnids are not spiders, but mites, and are generally not red, but yellow or orange . In addition to this, you often cannot see with the naked eye, but you can see on the leaves the marks left by their mouths, which puncture the leaves to suck out the sap. By itself this parasite is simple to eradicate, as it is sufficient to use a common insecticide and acaricide for the garden, to be sprayed on the leaves; in addition to this, periodic wetting of the leaves (even simply with the jet of water at the time of watering) contain a great deal of the population. However, it often happens that these arachnids also cause the development of bacterial diseases or the production of mold on the leaves; therefore it is advisable to remove the leaves that have many yellow spots, and to vaporize with an acaricide insecticide; or, since your plants are in pots, you can use a systemic insecticide, which will be supplied with the water of the watering, and will therefore enter the plant in a circle. It would be advisable to avoid using chemicals, however, on basil, since you eat it, so for basil it hopes that avoiding leaving the earth dry (or for long periods of time) and some vaporization with water from the foliage, will be sufficient practices to remove small mites.