Marijuana leaves will sometimes curl up or down from ph problems, heat problems , over watering or over fertilization. When the hook out to the side and with yellowing like in the picture you have Tobacco Mosaic Virus. Get rid of any plants with hooked out leaves. Eliminate any biting bug problems. Build your plants natural immunity with neem, amino acids and b-vitamins. Don't reuse pots, coco or soil from infected plants.
Sterilize with steam cleaners or boiling water. Spray alcohol to decontaminate pots(second time after steam or hot water), walls and tables. Keep your fingers crossed (along with the rest of you).Once you get rid of all the infected plants and everything else looks Irey don't go drooling over a bunch of bug and virus infested / infected clones and such. If you don't bring anything new in you won't have to fight it later.