Is this a beneficial caterpillar?
Hello My grapevine has an infestation of these small green caterpillars which are making cocoons inside gummed up tender leaves. Should the Vine be sprayed? If so with what type of spray?
Washtenaw County Michigan insects
That is probably a Grape Plume Moth larva (Geina periscelidactylus) The vines can tolerate some damage from them and usually outgrow them. If it is a heavy infestation and the caterpillars are in their early stages of feeding you can use insecticides with the active ingredient Bt (Bacillus thuringiensis) or Spinosad.