As hard as you may try to prevent it, it is inevitable that insects/bugs will enter your system at some point. Good preventive measures are to NEVER plant organic nursery seedlings without thoroughly washing them first, keep household pets out of your enclosure, and seal your enclosure (netting over airvents, etc) as best as possible.
Aphids on snow pea leaf.
Sticky Traps- Yellow sticky traps are a very good way to determine the type of insects/bugs in your system…as well as trapping them. The insects are quickly drawn to the yellow color, and cannot escape the sticky “glue” they contain. You can easily make your own traps, or you can purchase them on-line or at your local nursery. To make your own traps: Cut strips of yellow construction paper (about 3″x6″), punch a hole at one end to attach hanging string, then use a plastic knife to smear one side with the “glue” (Tree Tanglefoot Insect Barrier). Hang these at various locations throughout your enclosure.
Yellow sticky traps attract and trap insects.
Predatory Insects- Lady bugs, Praying Mantis and predatory mites released into your system in the evening can be extremely effective in controlling aphids, white flys and other types of harmful insects. They may be purchased on-line or at your local nursery. If you are using the spray methods below, please note that predatory insects may also be affected by these homemade sprays…so give one method a try first, then proceed to the next if not successful.
Ladybug Handling and Release:
- The best weather to release ladybugs is cloudy, cool, rainy weather – it makes them seek shelter rather than flying. Put them out nearly colonies of aphids or other food.
- The best time to release ladybugs is just before dark, in the cool of the evening, or even at night. They won’t normally fly at night, and need a “settling down” period after being handled.
- Spray the release area beforehand with water or (I prefer) a 10% sugar solution so they have something to drink. Maintain a high moisture level thereafter.
- Gently shake ladybugs from the container, spreading them around so that they can find food immediately. Release them on or at the base of infested plants.
- Piles of vegetation, stacks of boards or similar materials near dense vegetation are attractive to them as shelter on hot days.
- In greenhouses, screen vents or periodically apply chalk around vents and doors so that ladybugs can’t escape (they can’t cling to vertical chalked surfaces).
- In greenhouses, temperatures between 70° and 85° F are needed for reproduction. Temperatures above 100° F can be tolerated for short periods.
- Ants will “guard” aphids and other soft-bodied honeydew producing insects (like leafhoppers and scales) and protect them from predators like ladybugs. If ants are a problem, you might have to use a sticky product like “Tanglefoot” to make a barrier to prevent the ants from getting to the aphids.
- In order to get your ladybugs to stay as year round greenhouse guests, you should plant Umbellifera as a nectar and mating site for adults.
Ladybugs at work...
Ladybugs will also breed in your system.
Also a great natural predator...the preying mantis.
Spray Treatment- Never, ever use insecticidal sprays/soaps in an aquaponics system…they will harm your fish, and compromise your organic system. Instead, try “washing” them, first with a stream of plain water from a pump sprayer. This should wash away aphids and deter spider mites (which don’t like the moisture). If the insects are persistant, wash them with a natural, homemade spray: 1 quart water, 1 drop dishwashing liquid soap, 1 tsp Neem Oil (or other “dormant” oil). Holding a towel under the plant (to prevent the spray from getting into your system), spray the tops and undersides of your plant leaves and stems. This may be done twice a week in the early morning or evening.
If all else fails, gently remove your plants, and immerse them in your fish tank for a few minutes…the insects will drown, and the fish will love eating them as another source of protein. After removing the plants from the fish tank, gently replace into your system.
Mold/Mildew- Occasionally, you might notice mold or a white powdery mildew growing on your plant leaves…as the humidity in your enclosure temporarily exceeds an optimal level. Simply spray the leaves with a homemade solution: 1 quart water, 1 drop liquid dishwashing soap, 1 heaping tsp baking soda OR 1 part milk to 9 parts water. Either solution will have a dramatic effect on the control of mold or mildew. Use the same spraying method as for your homemade insect spray, holding a towel under the leaves as you spray.