That's the lily leaf beetle and the slug-like thing is its larvae. We grow several beds of Asiatic and Oriental lilies to sell to florists so they have to be pristine. We start patrolling for the beetles as soon as the lilies emerge from the soil in the spring and Tom checks them daily for new beetles and larvae, squishing as he goes. If you can't stomach the squish then drop them into soapy water. It might be too late for this year's flowers but start early next year to stay ahead of the infestation.
That's the lily leaf beetle and the slug-like thing is its larvae. We grow several beds of Asiatic and Oriental lilies to sell to florists so they have to be pristine. We start patrolling for the beetles as soon as the lilies emerge from the soil in the spring and Tom checks them daily for new beetles and larvae, squishing as he goes. If you can't stomach the squish then drop them into soapy water. It might be too late for this year's flowers but start early next year to stay ahead of the infestation.