ASK The Experts
We have an aquaponic garden in the basement of a three-story
building. Our garden is infested with aphids. We would like to use green
lacewings to control the problem but are concerned the lacewings
might infest other parts of the building. There is a preschool on the
first floor of the building. Any advice would be greatly appreciated.
– Cheryl
Hi Cheryl,
It is great you are so conscientious, both for considering
using beneficial insects to control your aphid problem, and
for considering the effects of releasing beneficials. Selecting
the correct variety of insects and releasing the proper amount
will help reduce any chance that an errant lacewing would
leave the feast of aphids and seek a meal elsewhere.
The green lacewing is an ideal beneficial predator to use for
the control of aphids. In their larval stage, they are known
as aphid lions due to their ravenous appetite for aphids.
Though they look more like tiny alligators (about an eighth
of an inch long), these lions can each consume up to 200 or
more aphids per week.
There are two main genera of this insect bred for use as biocontrols: Chrysoperla and Chrysopa. In your situation, I would
suggest obtaining the Chrysoperla carnea. The larvae of both
genera are aphid-hungry predators. The adult Chrysopa rufilabris is also a predator, but because of its wings and ability to fly,
it may leave your part of the building in search of other insects
to prey upon elsewhere, including the preschool. They feed on
many insects besides aphids, including other beneficial insects.
In the absence of prey, they will even cannibalize other lacewings. The adult Chrysopa rufilabris also has a moving mandible (jaw) and has been known to bite people on occasion,
though their bite is not serious to humans.
The adult Chrysoperla carnea, on the other hand, is
an herbivore and if it leaves your part of the building, it will do so in pursuit of nectar rather than
other insects. For this reason, and its lack
of a moving mandible, I think that
you would have no problem incorporating
these into
24
Maximum Yield USA | December 2014
your pest control approach. To achieve sufficient control, and
to discourage an exodus in search of an alternate food source,
do not release more than 1,000 of the green lacewings per 200
sq. ft. of garden area. If the infestation is limited to only a few
plants, release 5-10 lacewing larvae onto each plant.
To keep future aphid outbreaks at bay, keep a constant
population of green lacewings around your aquaponic
garden. They are generalist feeders and will help control
the populations of mealybugs, whiteflies, fungus gnats, mites
and thrips before they get out of hand.
Good luck,
Chris Bond
Chris Bond
Chris Bond is the horticulturist at Case
Western Reserve University in Cleveland,
Ohio. His primary role is coordinator of
the university’s Farm Food Program. His
research interests are beneficial insects,
biological pest control and alternative
growing methods. He is a certified
permaculture designer and nursery
technician in Ohio and a certified
nursery professional in New Yo rk.