These strange growths appeared on my basil plant stem. Removed one sample and it doesn't look like an insect (it's firmly anchored to the stem, and doesn't move). It is hard and relatively dry. What is this? Will it harm my plant?
Separately, my pearlite on the basil plant's soil surface is turning yellow with bumpy nodes too. Is this normal? what are those growths? I'm using a soilless potting mix for the basil.
Thanks, after a week more, it seems these are just adventitous roots! (They haven't turned brown, and are growing longer).
Turns out the roots were feeling a bit suffocated. Once I loosened the soil, adventitous root growth has slowed or stopped
The hard brown lumps are likely adult scale insects - these affix to the stem and don't move. The yellowish green bumps on the stems are young scale insects and will eventually turn brown and fixed. You do need to try to get rid of the scale or the plant won't grow very well - use rubbing alcohol on a Q tip to touch the brown scale and lift them off. For the rest, insecticidal soap should help, or neem oil spray, but you will likely need to repeat treatment. If you have other houseplants, check those in case the scale is present there.
This https://www.gardeningknowhow.com/edible/herbs/basil/basil-leaves-are-curling.htm mentions scale insect on Basil lower down in the article, with an embedded link to scale infestation on plants and how to treat it.
