I have some beautiful holly hocks and on the leaves (some on top and some on the bottom) there are black worms with spots of yellow on them. They are eating the leaves and are in cocoons with hundreds of eggs. I cut off a lot of leaves with the cocoons. Is there a spray for them? Gloria
I think you are describing a sawfly. https://homeguides.sfgate.com/worms-hollyhocks-62759.html Sevin will kill the worms but it also kills bees.