| The codling moth, Cydia pomonella, is a serious
pest on apples, but it can also do damage to pears,
plums, quinces, and walnuts. Injury to apples is
caused by the codling moth larvae, which tunnel
into the fruit, usually to the core. Damage is
restricted to the fruit; the larvae do not cause
damage to other parts of the tree.
Symptoms and Diagnosis
Larval feeding damage is either "stings" on the fruit
skin or tunnelling within the fruit. A "sting" is the
result of a larvae taking one or two bites of the fruit
which causes a surface blemish. If the larva
continues to feed at one site, a deep entry or tunnel
will be the result. The tunnel openings are
surrounded by the crumbly, brown fecal matter of
the codling moth larvae. The feeding damage causes
fruit to rot and drop prematurely, reducing yields.
Life Cycle
The adult moth is a small gray-brown moth with
pale, fringed hind wings. Their wingspan measures
only 3/4 inch wide. Larvae, when fully developed,
are 1 inch long worms with pinkish or whitish
bodies and dark heads. Only fully grown larvae
overwinter. Larval or pupal stages overwinter in a
thick, silken cocoon under the bark of trees. Adult
moths first emerge from the cocoons in the spring,
when apple trees are in bloom. Females lay eggs
during flower bloom. Young larvae tunneling
through the developing fruits feed and emerge to
pupate under the tree's bark. After the larvae pupate,
a new generation of codling moths emerges in the
midsummer. In Missouri, three generations occur
every year.
Integrated Pest Management Strategies
1. Monitor for codling moth. Hang sticky apples
prior to petal fall. As soon as moths appear, begin
your control strategies.
2. Tie paper bags around the developing fruit. This
technique will protect the fruit from pests. This
technique is feasible only for low numbers of
trees or fruit. This should be done in early May or
June, after pruning.
3. Trap mature larvae before they can pupate with a
band of Tanglefoot painted around the bottom of
the tree trunks.
4. Spray trees with Bt (Bacillus thuringiensis) later
on in the season to kill larvae. Repeat at 7–10 day
intervals until larvae stop emerging.
5. Apply horticultural oils before the buds begin to
open in the spring. This treatment will suffocate
the pupating larvae if the entire tree is sprayed.
6. Apply insecticides. Pesticides registered for use include carbaryl (Sevin), cyfluthrin, permethrin and spinosad. Apply as soon as adults appear. Make 2-3 applications, 3-5 days apart. |
