whiteMemphis wrote:
Hi all, anyone here grow apples, and if so, what do you do about codling
moth? thanks any feedback


Codling moth is not a great candidate for biological pest control, as
the larvae are well protected within the fruit for the majority of
development. However, codling moth eggs are susceptible to biological
control by Trichogramma wasps. The wasps deposit their eggs into codling
moth eggs, and the developing wasp larvae consume the moth embryo
inside. Another method for control and sampling, 'trunk banding',
consists of wrapping a corrugated cardboard strip around the tree trunk.
Larvae making their way back to the tree to pupate after the infested
fruits are aborted will use bands as pupation sites. Bands may then be
removed and burned.

Codling moth infestations are often managed with pesticides. Successful
synthesis of codlemone, the codling moth female sex pheromone blend, has
led to behaviorally based monitoring and management. Pheromone traps are
used to capture male moths for monitoring and setting biofix, which is
the time of first flight for codling moth. Biofix is used with weather
data to run degree day models (see below) which predict with excellent
accuracy the phenology of the population in the field, thereby allowing
growers to time their management actions to target codling moth when
they are most susceptible. A kairomone which is a feeding attractant can
be used to capture males and females (DA lure). Mating disruption can be
used to effectively manage codling moth populations in many cases.
Mating disruption involves the use of a pheromone impregnated release
device, typically made of plastic or rubber. Dispensers are distributed
throughout the orchard and emit female pheromone at a high, relatively
constant rate. The mechanism by which mating disruption affects males is
poorly understood, it may increase the time required for males to find
females, thus reducing fecundity, or it may simply mask the position of
females to searching males, reducing mating substantially.

Recent trials of non-toxic kaolin clay-based sprays indicate that an
effective alternative means of codling moth suppression may be on the
horizon. Codling moth and other pests find leaves and fruit covered in
kaolin clay unfit for laying eggs. Tiny particles of the clay tend to
attach to their bodies, disturbing and repelling them. In addition,
trees covered in kaolin clay can make them less recognizable as habitat
to codling moths. Full coverage of trees is necessary in order to
achieve effective suppression. If used only at the beginning of the
fruit growing season, kaolin clay often comes off by itself due to wind
and rain attrition, leaving fruit clean at harvest time.

The prime difficulty in dealing with codling moth infestations seems to
lie with appropriate timing. The method of calculating 'degree-days' is
often used by orchardists to approximate when a particular pest will
reach a particular stage of development during a given season. Since
stages of insect development are triggered by the accumulation of a
certain amount of heat over time, this calculation involves careful
tracking of changes in daily temperature. In the case of codling moth,
pupating larvae emerging from bark and other overwintering spaces will
migrate and burrow into apples soon after petal fall. For a given larva,
this migration takes place within a mere two to three hours. Effective
control using any method therefore depends crucially on identifying when
decisive moments such as these occur.