What should I do? Plague in leaves

With one small plant,whatever treatment you use don’t spray use a q-tip and rub back and front of leaf it’s more timely but just one small plant I’d do it you save the buds getting sprayed in flower

that is a black aphid & a fat one at that. They suck up the plants life force and excrete honeydew or sap as they can't process all the sugar. This excess sugar will encourage rot on the leaves if left unchecked and will be inviting of other pests as its sweet smelling. common dish detergent and water kills them pretty good. also rubbing alcohol, however alcohol will dissolve some of the trichombes as they have solubility in it. If you close to a good greenhouse, you can get predatory bugs that eat aphids. this is the greenest option and safest for the plant in flower. Some of the eggs may drop in the soil so you will need multiple treatments above to wipe out the infestation. on the plus side, If you live someplace where its warm right now, find some ladybugs or ladybirds, they love to eat aphids. red/orange/yellow shell they eat em all the same. I'd use the dish soap method. 15-20 parts water to 1 part dish soap, combine in mister and set it to fine mist. "optional combine with neem oil" [natural insect replant] let it sit on for 15 min. Then rinse off under a tap or shower. Do NOT do this under grow lights. The lights can be to strong and the water beads act as mini magnifying glasses/prisms and burn the leaves. best of luck

I use a product called green cleaner - it’s expensive but works.. neem will work too but it lingers in the smell when you spray in flower

Hello. There are a few things you can do, Mix some Hydrogen Peroxide (see the internet to get the right dilution) I think it's 1% and spray on the leaves. Mix some isopropyl alcohol in water about 1/2 and 1/2 and add a few squirts of dish soap and you can add some hot peppers to that mix. That will fry them. Beatles can fly but you can add some 2 sided tape around the pot to catch them if they are crawling up. Put some eucalyptus oil on some cotton balls and put where the pests are. they will move. Please don't spray neem oil, it's been found that it contains heavy metals which aren't good for you.. Good Luck. Chuck.