Slugs Snails Or Earwigs

Stems that look chewed like this are usually stripped by slugs, snails or earwigs. Once they girdle a stem there is no saving the plant. Usually this sort of damage appears shortly after you plant annuals, since the new plants are tender from the grower. Once they’ve been in place for awhile the plants toughen up and the pests no longer find them attractive. To prevent this from happening in the future, right after you put the plants in the ground dust them with diatomaceous earth, getting the powder on the stem, leaves and surface of the soil. (There is a good video on Youtube about how to make a DE applicator out of an old plastic water bottle.) Usually you only have to dust the plant right after you put it in, although you’ll need to water the plants well first and let them dry before applying the diatomaceous earth. (watering and rain make the DE less effective.) This is a good idea when planting Cleome, marigolds and dahlias as these pests seem especially fond of those annuals.