Coddling Moth
Coddling moth is a common problem in apple trees (including crab apple), pears and quinces leaving drill holes in your beautiful fruit. The adult moth lays its eggs at dusk, near or on the emerging fruit. The larvae start by chewing their way though the apple and into the core of the fruit. The first entrance hole from the lava begins very small and often goes unnoticed. The lava then feeds on the core for three to five weeks and then enlarges the hole pushing out leaving sawdust like excreta.
The grub (now fully fed on your fruit) walk down the branches searching for a suitable place to pupate often under the bark or crevices in the trunk of your tree. You may have heard people recommend using cardboard as a wrap or barrier glue around the stem of trees, catching the grub in the manner whilst searching for a place to pupate. Unfortunately the main damage to your fruit is often already done however this is beneficial and will act in reducing any grubs for the following year.
Coddling moths begin to fly in spring at approximately the time the earliest apple and pear varieties reach pink bud stage. Female moths usually fly to the tops of apple trees to call for their mates and lay eggs singly on or close to the fruit. Eggs laid in early spring may take 20 days or more to hatch depending on the temperature, while those laid in summer may take only 7 or 8 days in the field. Larvae entering the apple take 40 to 55 days to develop, they then emerge from the fruit, pupate and become adults.
Organic controls are effective although you need to be vigilant and destroy infested fruit as well as remove flaking bark and broken branches in conjunction with any litter at the base of your tree. Applying Eco Oil to cracks & crevices offers some added organic protection. Other less toxic options include the codling moth traps, which work by attracting male coddling moths through a pheromone (sex scent) lure.
The traps are best used when set from the start of flowering until the end of harvest. Keep in mind it is important to replace them every 4 - 6 weeks throughout this time. Alternatively you could use Yates Success ultra, which is a widely used and effective insecticide spray which is registered for use on fruit trees however it can be harmful to bees and we would only recommend using in the evenings, when bees are not active.