Ladybugs

Asked June 3, 2014, 12:25 PM EDT

We have a honey locust tree in our yard that is infested with aphids. I was planning on buying ladybugs to help, but heard that "ladybugs that you can purchase for your garden are trapped in the wild, and ... can carry parasites and diseases that will infect ladybugs native to your area". Is this a concern or do you think it's a fine solution for aphid control? Thanks!

Multnomah County Oregon ipm

1 Response

Here are two articles that should help answer your question and provide additional information about various ladybugs. Thanks for your question.

The fact sheets found at http://ohioline.osu.edu/hyg-fact/2000/2002.html and http://ohioline.osu.edu/hyg-fact/2000/2154.html give the positive and negative aspects of purchasing and releasing these insects. In a nutshell, the puchased ladybugs are generally a species native to California and do not stay around for very long, nor do they feed on pests or reproduce as well as local species. For praying mantids, the Ohio populations are actually on the increase making purchasing egg cases from elsewhere somewhat questionable. The other reality is that mantids will not give total pest control alone and are generalists consuming not only pests, but other beneficials and each other as well.
What may be better than purchasing from out of the area is to preserve local populations by avoiding unnecessary insecticide applications or use ones soft on beneficials as well as growing nectar producing plants such as dill, yarrow, angelica, marigolds, sunflowers and buckwheat, just to name a few, that will attract a variety of native beneficial species to your growing area. Even butterfly gardens -see http://ohioline.osu.edu/w-fact/0012.html, or cover crops-http://ohioline.osu.edu/sag-fact/pdf/0009.pdf can attract beneficials as well. One other quote from http://ohioline.osu.edu/hyg-fact/1000/1257.html is: "Predators such as ladybugs and praying mantises can be released, though they seldom stay in the garden long enough to provide long-term control. Release of parasites such as trichogramma wasps can be effective, though it may not be worth the expense for small gardens. " Also see http://ohioline.osu.edu/hyg-fact/2000/pdf/2205.pdf for more information.


They are
oval (shaped like an egg), with six
legs and two antennae.
The body usually is red or orange
with black spots, and the head is
black with white markings. Some
species have yellow or even black
bodies, and some have no spots.
A lady beetle’s shell is actually
two wing cases known as elytra.
Under the elytra is a pair of delicate
wings.
Lady beetles go
through a complete
life cycle known as
metamorphosis from
egg to adult. This
process usually takes
about 3 to 4 weeks.
Although most lady
beetles live only a
few months, some
can live for more
than a year.
Females lay up to
50 yellow eggs at a
time on a leaf
or branch. One
female can
lay up to
1,000 eggs
during
her
life.
The eggs hatch into dark-col-
ored larvae about
1
25
to
3
8
inch (1 to
8 mm) long. The larvae feed on
aphids and other insects. This stage
lasts about 20 to 30 days, during
which the larvae grow and molt
(shed their skin) several times.
Next, the larvae enter a pupal
stage (similar to a moth cocoon or
butter
fl
y chrysalis). This “resting”
stage usually lasts 3 to 12 days, and
the pupa doesn’t eat during this time.
Finally, an adult emerges from
the pupa and searches for food and a
mate.
Species descriptionWhere they live
and why
Lady beetles live throughout North
America. Their habitats include gar-
dens, farms, meadows, schoolyards, and
woods—anywhere there is food. During
the warm summer months, they usually
live on
fl
owers, branches, bushes, and
farm crops such as vegetables because
they can easily
fi
nd prey in these places.
Lady beetles seek shelter under leaves,
branches, and other plant parts. Shel-
ter protects them from bad weather and
predators.
When temperatures start to drop in
the fall, lady beetles seek shelter for the
winter. Otherwise, they would die from
the cold. People often
fi
nd lady beetles
Creating habitat
The right kinds of
plants are crucial for
attracting lady beetles.
Flowers that produce
lots of pollen and nec-
tar, such as angelica,
yarrow, marigolds,
roses, dahlias, daisies, aster, and dill, are
good.
The use of insect poison (pesticides)
should be restricted because bene
fi
cial
insects can be killed along with pests. A
healthy garden should have lots of ben-
e
fi
cial insects that help keep damaging
insects under control.
A pile of yard debris can attract lady
beetles. The pile should include branches,
leaves, large and small pieces of bark,
long grass, and any other debris that
accumulates in your yard. Yard debris cre-
ates shelter for lady beetles and provides a
place for them to gather in the winter.
Lady beetles can be purchased, but
when they are released they usually
fl
y
away. Purchasing lady beetles is not rec-
ommended because it removes them from
their native areas and can deplete natural
populations. Also, most lady beetles avail-
able for purchase are exotic species that
compete with native species for food and
shelter.
Lady beetle house plans
To provide winter shelter for lady bee-
tles, you can build or purchase a lady beetle
house. Plans are available online at http://
butter
fl
ywebsite.com/Articles/MQuinn/
MQuinn1.htm
in their houses in the fall. During the
fall, lady beetles gather in large groups,
sometimes numbering in the hundreds or
thousands.
Fun facts
Lady beetle wings
fl
ap at a rate
of 85 beats per second.
The convergent lady beetle got
its name from the converging
white lines on its body.
Lady beetles emit a smelly yel-
low substance when they are
handled by predators or people.
This smelly substance is actually
their blood, and it keeps preda-
tors from eating them.
Lady beetles often try to spend
the winter in houses.
© 2007 Oregon State University.

Learn more!
Cornell University. http://www.nysaes.
cornell.edu/ent/biocontrol/predators/
hippodamia.html and http://www.
nysaes.cornell.edu/ent/biocontrol/
predators/ladybintro.html
Lady beetle house plans. http://
butter
fl
ywebsite.com/Articles/
MQuinn/MQuinn1.htm