Container Garden Pests & Plant DiseasesPests and plant diseases tend to attack plants in outdoor planters that are weak or stressed. Occasionally conditions may arise that invite pests or diseases to attack even healthy-looking plants.Wood planters make particularly attractive homes for some pests like ants and sow bugs. These pests will cause more damage to the planter rather than the plant and should be removed whenever they appear.Regularly checking your plants for signs of insect damage, and finding the culprit quickly should prevent any major problems. Some of the most common pests you’ll find in garden planters, depending on the region, are slugs and snails. These are quite easily discouraged by placing broken eggshells over the surface of the planter soil. These critters don’t like walking over the rough edges of the eggshells and they’ll go off in search of easier victims!AphidsAphids can usually be controlled by removing with a strong spray of water from a hose and a couple of follow-up sprays with soapy water for the persistent bugs. Beetles and earwigs love to munch on juicy leaves and then hide under planters, so check for unwanted residents underneath your garden planters and remove manually. As a last resort, insecticidal soaps can be effective as long as the spray hits the insect directly.Ladybugs are considered one of the most beneficial insects in your garden as they’re capable of consuming up to 50 to 60 aphids per day! One rule of thumb when dealing with garden pests in your container garden is to make sure you know what type of insect you’re dealing with. Many insects are beneficial to your plants and actually keep the ‘bad’ bugs away.Beneficial InsectsBeneficial insects fall into these main categories:Pollinators: we depend on these insects—including bees, butterflies and even some flies—to pollinate our garden’s flowers.Predators: these insects eliminate pests by eating them. Insects like ladybugs, praying mantis and green lacewing larvae fall into this category.Parasites: parasites also prey upon other insects, but in a slightly different way. They lay their eggs on or in the bad bugs, and when the eggs hatch, the larvae feed on the host insects. Parasitic wasps are the main member of this category.Plant DiseasePlant diseases are seldom a problem in garden planters. Proper drainage and good air circulation will help prevent root problems such as rot, and removing any leaves that show fuzzy white patches, indicating powdery mildew, should prevent any serious problems.