Contrary to popular belief, pest control is still an issue for the indoor gardener. In fact, dealing with insects can be more difficult for indoor growers than it is for outdoor growers. Creating a completely sterile, pest free environment is very difficult and an indoor grow environment is excluded from the outdoors to a level that doesn’t usually deter incoming pests, but almost certainly excludes the presence of the predatory insects that balance them. Remember that while pest insects possess a hearty degree of resilience and adaptability (these traits are considered a “must have” in order for them to survive constant predation), the predatory insects that feed on them tend to reproduce slower and seem to have a significantly harder time finding their way to an indoor system, particularly in the winter months when most insects are dormant.
In the absence of predatory insects, many gardeners turn to insecticides. However, using insecticides to control pests indoors can be tedious work. Plants must inspected regularly to check for any signs of insect damage, as a pest problem that is left unattended even for a few days quickly becomes an unmanageable nightmare. Once pests are spotted, the grower must begin a faithful regiment of spraying at specific times of the day (when the sun is low or the grow lights are on their “off” cycle to avoid burning). All the while, he must deal with the worry that his plants will need to be ripped out and destroyed to make any headway. Apart from their use as a temporary quick fix, insecticides are inconvenient and tedious.
Some companies have begun breeding and selling predatory insects to commercial and hobbyist growers. There is now a large selection of predatory insects available to growers, covering a wide variety of pest control needs. Using an external supply of predatory insects allows the grower a more “hands-free” approach to dealing with pests, as well as being able to provide protection and prevention for future pest problems.
Introducing natural predators into an indoor grow environment provides it’s own unique set of challenges. Some care must be taken in selecting the proper beneficial insects to introduce. Some beneficial insects are sensitive about their ambient temperature and their humidity (fortunately, most beneficial insects prefer the warm, humid environments that indoor aquaponic systems provide). In an indoor environment, the insects selected should also be small and inconspicuous, as very few people seem to appreciate the thought of releasing 2,000 ladybugs into their garage or household. There are a large variety of predatory insects marketed for pest control. Not every insect is ideal for the indoor gardener, but here are a few of my favorites:
The bright orange larvae of aphidoletes aphidimyza (predatory midge) are renown for their ability to consume large colonies of aphids. They are ruthless, often killing more aphids then they can consume; one larva can kill and consume up to 50 aphids in a single day. The adult midges possess a great tracking ability, making them ideal for controlling large infestations, as well as finding the smaller colonies that spring up afterwards. They are also not selective about which aphids they eat, and are known to have over 60 species of aphids within their dietary preference.
Their efficiency can also be a downside, as they tend to eventually eat themselves out of a job and fly outside to find other food sources. They are also very sensitive to pesticides, so insecticides of any kind should be avoided where their presence is desired. Note that the adults lay their eggs in soil, so media should be provided for egg laying purposes
Even though the idea of ordering wasps may make some people uncomfortable, A. colemani only measures in at a max. length of 3mm, meaning as far as wasps go, they are quite inconspicuous. These wasps are parasitoids that lay their eggs directly inside of aphids. The larvae develop inside of the living aphid until they are ready to pupate, after which they kill their host. Female wasps lay around 100 eggs each, often killing extra aphids in the process. A. colemani are best used as a preventative measure and for control of smaller aphid colonies, although care should be taken to identify the specific species of aphid that needs control, as this parasitoid doesn’t work for every common aphid species. If A. colemani doesn’t fit your specific needs, then look at some of the other wasp varieties in the Aphidius genus, such as A. ervi.
If dealing with a current spider mite problem, then this is the predatory insect for you. P. persimilis is a mite that specializes in consuming two-spotted spider mites. The red mite has a large, refined appetite, and is more ideal for quickly cleaning up existing spider mite colonies, rather than for preventative control. I recommend using them in combination with other varieties of mites to round out your pest control program.
This mite works great in tandem with P. persimilis. Unlike P. persimilis, N. Californicus doesn’t eat spider mites nearly as fast, but it can live off of flower pollen as a alternate food source, making it an ideal partner for long term prevention plans.
Not long ago, purchasing beneficial insects wasn’t very practical for the hobbyist grower. Because predatory insect suppliers only sold and shipped in larger quantities for commercial farms, purchasing beneficial insects was really only economical for larger operations. However, some companies have begun selling these insects in smaller quantities, and in forms that are better catered to hobbyist growers (such as slow release packets). As a result, the buy in for introducing predatory insects into a small grow environment is beginning to decrease in price. Currently, my favorite distributors of predatory insects are:
Green Methods: https://greenmethods.com/
Evergreen Growers Supply: http://www.evergreengrowers.com/
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