Apple
Codling Moth Not to be Coddled
By Mary Giambalvo, Master Gardener
Remember the old riddle asking what is worse than biting into an apple and
finding a worm? The answer, I recall,
was finding half a worm. That always
stopped me mid-bite.
Those wormy apples are no joke if they hang on your backyard tree in large
numbers. Chances are the tree is under
siege, not by worms, but by the apple codling moth, a major pest for farmers
and home gardeners alike.
The apple codling moth, which also attacks pears, walnuts, and, to a lesser
extent, plums and other stone fruits, is the size of a housefly and lays its
eggs in early spring on leaves and fruit or nuts.
When the eggs hatch, the resulting larvae burrow their way into developing
fruit to eat and grow. They create a
tunnel plugged from behind with larval droppings. At the end of their growth spurt, they exit
the fruit and drop to the ground, seeking shelter for the winter so they can
start the whole process over. In mild
climates, two to four generations can reproduce in one year.
Without attempts to contain them, the numbers will increase until a
neighborhood or farm is infested.
Several techniques can help. Practicing
sanitation by cleaning up all debris under the trees will leave the dropping
larvae nowhere to hide. Remove infested
fruit from the tree by checking them for entry sites as they develop.
Bagging the growing fruit with lunch-sized paper bags will protect it from
invasion. Pretty? No, but neither are apples shot with dark
holes. This works best on trees that are
kept small enough for the gardener to reach.
Some people use pheromone traps to snare the male moths in early spring. This can be tricky because the timing must be
right, but it may lower the populations.
Others band the trunk with corrugated cardboard to catch the crawling
larvae as they move to a protected area to pupate. Put the bands up at bloom, and pull them off
on July 4th. Do it again in September,
and destroy the bands on New Year’s Day.
It’s another way to celebrate the holidays.
Another method is mass trapping, using a recipe of 1 cup cider vinegar, 1/3 cup
dark molasses, 1/8 teaspoon ammonia and enough water to make 1 1/2 quarts. Put the mixture in a plastic jug with a 2
inch hole cut near the top. Hang the jug
from the infested tree. This will trap
both male and female moths if the timing is good.
It may take several seasons to lower the codling moth population, using several
of the above methods combined. Unfortunately,
if highly infested trees in the neighborhood go untreated, they can provide an
ongoing source of more codling moths.
Pesticides require critical timing and careful following of the labels, making
them a less desirable way to eradicate the codling moth for the home gardener. If the larvae have already crawled into the
fruit, they are protected from sprays. Honeybees
and other beneficials, however, can be harmed.
While the apple codling moth is no joking matter, there are steps to lower its
numbers in our yards and provide us with apples whose only surprise inside is
good taste.