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Identifying characteristics-
Aphids are round, soft-bodied insects usually 1-3 mm. Colors vary from
black, brown, green, yellow, red, and even pink. Some species are covered
with a waxy fluff but most are not. There are over 400 species
of aphids know.
They are normally found in large
groups, sucking on plant juices. Aphids are usually wingless but can
sometimes have wings for migration. The key to identifying an aphid is to
look for structures called cornicles. They are tube like, and found on
the backside of the body. They are used to secrete defensive fluid.
Aphids also secrete honeydew through their anus; this causes sooty mold to
grow on plants. Aphids are usually found feeding on new, tender plant
growth.
Biology- The adult aphid feeds
on plant sap using a thread like mouthpart. They stick it into the plant
and feed while injecting their saliva. This can cause damage to the
plant.
For the most part aphids give birth to
live young. They only lay eggs when going to overwinter. This allows
them to have many generations per year. As the population grows, aphid
that will develop wings will be born. The winged individuals will be able
to migrate to new plants to start new colonies. Highest populations are
found in spring, but can be found all year round.
Plant injury symptoms- Infested
plants have distorted new growth such has curled or hardened leaves. The
leaves also can have white flakes which are the cast skins of aphids.
While feeding, a sticky waste substance is excreted by the insect
(commonly called honeydew). This liquid adheres to leaves, and provides a
medium for sooty mold to colonize and grow on. Sooty mold is black, and
eventually covers leaves and stems. This mold inhibits infected portions
of the plant from photosynthesizing, and also causes aesthetic damage.
Ants are often present to feed on the honeydew, and will farm the aphids
like cattle.
Aphids can also transmit
/ vector plant
viruses.
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 Aphids
Aphid “mummy”
Aphid that has been parasitized by a wasp |
