A common misconception of hydroponic gardening is that you never have to worry about dealing with pests and bugs. Many growers wish this was true because the fact of the matter is that even in a soil less garden you have to deal with some of the same kinds of critters that can damage traditional gardens. Fortunately, with a little knowledge and quick action, you can easily prevent or minimize the damage caused by bugs to your plants and hydroponics supplies.
Here are a few of the more common pests found on plants in hydroponics systems.
Aphids - They are numerous varieties of aphids and their coloration can vary from black, brown, very light colored, or yellow. They often leave a sticky residue on your plants which causes the plants to grow in a deformed or twisted manner. They also typically carry viruses that can affect the growth or even kill your plants. A typical sign of an aphid infestation is the presence of little white exoskeletons which the aphids have molted off. After identifying that you have an aphid problem, you should remove the damage leaves, wash the remaining leaves, and spray them with an insecticidal soap.
Whitefly - Whiteflies are typically seen in larger systems that use more extensive hydroponics supplies. They often resemble very small moths but they actually more closely related to aphids. They often hide on the underside of leaves, sucking juice from them and causing serious damage. Like aphids, they are also carriers of numerous plant diseases, and can wreak havoc on your garden if unchecked. The most effective way of dealing with whiteflies is through biological control. A wasp called the Encarsia Formosa is a natural enemy of the whitefly. Introducing the encarsia to a whitefly infected garden has proven to be an effective and safe way to deal with this pest.
Fungus Gnat - The fungus gnat, also known as the sciarid fly, is a tiny black fly. The adult flies don't cause any damage to your plants directly, but can carry spores of fungi that can harm them. The real damage of the fungus gnat is in the larvae, which will feed on anything organic for a period of two weeks. The fungus gnat can be controlled with just about any general purpose insecticide. For larvae, it may be necessary to drench your medium in insecticide. When doing this it is a good idea to only start with one small section to see how it will affect your plants.
Spider Mite - Spider mites are very small, usually about 1/20th of an inch in length, so you may need a magnifying glass to identify them properly. They have eight legs, an oval shaped body, and two red dots on their backs. They can cause damage to your plants by sucking the contents of your leaves. There are several biological options for controlling spider mites. Their natural enemies include the western predatory mite, the sixspotted thrips, and the spider mite destroyer lady beetle.
If using hydroponic supplies such as an insecticidal soap to kill spider mites, make sure not to use any on water stressed plants, as this may cause further damage. You do, however, need to make sure to cover the affected areas thoroughly because spider mites need direct contact with the insecticide to die.