Snails and slugs often hide in the potting media where they chew on young root tips; they also come out at night to chew on the leaves and stems. There are several insect pests that are common: Aphids (small sucking insects) and thrips (small chewing insects) attack tender new growth, flowers and buds. Scale insects form a brown or black crust on leaves and stems. Mealybugs also attack the leaves and stems forming a white cottony mass. Consult a local garden center for products to control these pests.