Effect of pesti/fungi/cides on tender, new leaves

Are the young, just emerging, tender, tiny leaves of the trees affected when sprayed with any of those chemicals?
I had to give some sprays during the previous months and I noticed that after one day the young leaves of pyracantha, myrtus and rose turned black and died of course while other species did not.
Does the -cides have played a role to this?
And if affirmative, how can the spraying be effected without harming new leaves?

Thank you.

The epidermis of new leaves is very thin, although it hardens off fairly rapidly. It is entirely possible that -- depending on what chemical you used and what it was dissolved in (e.g. alcohol?) -- the spray could have damaged the leaves.

Turning black seems unusual to me, though.

Thank you, Jim.
So, I presume that if a tree has some problem which should be addressed using a chemical product and this tree is in full growth with new tender leaflets, then it is most probable that those leaves will die.... and perhaps that depends on the species. Am I right?

It may not be the pesticide itself. It is more likely the carrier. For a sensitive plant, look for a different formulation, such as granules applied to the soil or dust, rather than spray. Also, check the directions carefully. The damage may be from spraying too close to the plant, in full sun, in excessive heat, etc. Also, different plants sometimes require a different strength of spray.
Many pesticides carry a warning on the label: "May damage new growth."
Iris

Thank you, Mrs. Iris!
As you said, perhaps the heat has played its role... detrimental role even though I did spray in the morning.

I'll take this opportunity for my standard advice to READ THE LABEL. At least in this country, the label will give dosage requirements. It will give warnings about the effects of that chemical on humans, animals including, especially fish and amphibians), and plants. It will tell you what insects the chemical is approved for use on (usually almost anything), what crops it can or cannot be used on, the ornamental plants that it is approved for and, often, plants that should NOT have this chemical applied to.

And, as Iris and I said, it often may be the delivery system that causes the damage -- aerosol sprays should not be held very close to the plant, for instance, or the alcohol or other solvent material into which the chemical is dissolved may dry or burn new leaves. The delivery system and othe chemicals probably will be listed on the label as "inert" ingredients, but Inert is a relative term.

Sometimes, however, even innocuous pesticides, like soap sprays, can be dangerous. Be careful applying soap sprays on maples -- especially trident maples. Also be careful of oil-based sprays in the summer and to plants that are in the sun -- especially so-called "dormant oils". The oil heats up in the sun and will cook the leaves.

That's why I often suggest that a hard spray of water into the canopy may be as good a control mechanism as a massive chemical arsenal.