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Of
all the insects in the garden, the ladybug is probably the most
easily recognized. Ladybugs, also called lady beetles or ladybirds,
are a gardener's best friend. Not only do they feed on insect
pests, especially aphids, but their bright coloring also brings
cheer into the garden.
Attracting them into your garden
requires some planning but can help immensely with your pest
control. However, if you just don't have the space to plant the
types of plants that ladybugs like, releasing commercially bought
ladybugs can help you clean up infested plants while you work
to establish your own population.
Identification
Adult lady beetles are usually
oval or domed shaped, and can range in colour from red to orange.
The number of black markings can also range anywhere from no
spots to 15 spots. Some species are even solid black or black
with a red spot (the Twice Stabbed Lady Beetle).
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The young, larval form of the
ladybug is often less recognized. They tend to resemble tiny,
six-legged alligators, blue-black in colour with orange spots.
Often, gardeners unknowingly squish or spray the larval form
of the ladybug, not knowing what a benefit they are to the garden.
Both adults and larvae feed on
many different soft-bodied insects but aphids are their main
food source. One larva will eat about 400 aphids during its development
and single adult can eat a whopping 5,000 aphids in its lifetime.
In addition, they will also eat other insects such as mealybugs
and spider mites as well as the eggs of the Colorado Potato Beetle
and European Corn Borer. |
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Life Cycle
Within a year, there can be as
many as 5-6 generations of ladybugs as the average time from
egg to adult only takes about 3-4 weeks. In the spring, adults
find food and then the females lay anywhere from 50-300 eggs.
The tiny eggs are yellow & oval shaped and are usually found
in clusters of 10-50, near aphid colonies. The eggs take 3-5
days to hatch and the larvae voraciously feed on aphids for 2-3
weeks before they pupate into adults.
In the fall, adults hibernate
in plant refuse and crevices. They often do this en masse where
several hundred adults will gather at the base of a tree, along
a fence row or under a rock. They especially like areas where
leaves protect them from cold winter temperatures.
Attracting Ladybugs in the
Garden
Apart from aphids, ladybugs also
require a source of pollen for food and are attracted to specific
types of plants. The most popular ones have umbrella shaped flowers
such as fennel, dill, cilantro, caraway, angelica, tansy, wild
carrot & yarrow. Other plants that also attract ladybugs
include cosmos (especially the white ones), coreopsis, and scented
geraniums, dandelions.
Apart from planting attractive
plants in the garden, you can also promote ladybug populations
by cutting back on spraying insecticides. Not only are ladybugs
sensitive to most synthetic insecticides, but if the majority
of their food source is gone, they won't lay their eggs in your
garden. As difficult as it may be, allowing aphids to live on
certain plants is necessary to ensure that there is enough food
for ladybugs. In addition, resist the urge to squish bugs &
eggs in the garden, unless you're certain that they are not beneficial.
Purchasing Ladybugs
Sometimes, there just isn't enough
room in the garden to have ladybug-attracting plants or you or
your neighbour may have been over diligent with the pest control.
In certain circumstances, purchasing ladybugs can help to control
a severe problem or help a population become established.
Scientists have found that indoor-reared
ladybugs fail to find their own food when released outside so
the majority of commercially available ladybugs are collected
from the wild. Before releasing them into the garden, here are
a few tips to help ensure that they stay where you want them:
1. Only release ladybugs after sun down or before
sun-up. Ladybugs navigate by the sun and in the evenings &
early mornings, they tend to stay put.
2. Pre-water the area where you are releasing them.
Not only will the ladybugs appreciate the drink, free-moisture
on the leaves helps the ladybugs to "stick" to plants.
3. In the warm months, it helps to chill the ladybugs
in the fridge before releasing them. Ladybugs tend to crawl more
than fly in colder temperatures and the overnight stay in the
fridge won't harm them in anyway.
4. On severely infested plants like roses, drape
a floating row cover or thin sheet over the plant and release
the ladybugs underneath. Within a day, the ladybugs will have
found the aphids and will be happily munching away at them.
One Note: The Asian Ladybug
If you are planning to purchase
ladybugs for your garden or greenhouse, I encourage you to select
the native ladybugs species, Hippodamia convergens, rather than
the Asian ladybug, Harmonia axyridis. Although the latter is
very effective at controlling aphids and is often the species
of choice for commercial greenhouse growers, it is the main cause
for "ladybug infestations" inside houses.
While the native ladybug is happy
to hibernate outdoors, the Asian species requires warmer temperatures
and often ends up becoming a pest to homeowners as it congregates
in large numbers inside. In addition, it seems to be establishing
fairly large numbers in the wild and there is some concern it
will begin competing with the native species. Some suppliers
of predatory insects do sell both species and it's best to choose
the native one if you can. |