Codling moth is a common problem in apple trees (including crab apple), pears and quinces leaving drill holes in you beautiful fruit, The adult moth lays its eggs at dusk near or on the emerging fruit. The larvae start by chewing the 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
Codling moths begin to fly in spring at approximately the time the earliest apple and pear varieties reach pink bud stage. Virgin female moths usually fly to the tops of apple trees to call for their mates. They fly at dusk and are attracted by profiles of tree silhouettes. Highest numbers of Codling moths are frequently found near edges and high spots in orchard blocks.
Male moths locate females by flying upwind, criss crossing over trails of pheromone produced by the female moths. As soon as a male moth gets out of the pheromone plume, it turns back. In this way it homes in on the twig where the calling female is waiting.
Most females mate within an hour of the onset of calling (emission of pheromone into the air).
Mated female moths are usually sedentary, few moving beyond five or six trees from where they emerge if there is no shortage of apples or pears on which to lay eggs. However, they will fly considerable distances from packing sheds or bulldozed trees if there is no suitable fruit close by. In heavily infested orchards, the small proportion of the total leaving the orchard may still be enough to cause considerable problems for neighbouring blocks.
Codling moths lay eggs singly on or close to 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 from 40 to 55 days to develop, emerge from the fruit, pupate and become adults.
In areas supporting three generations of Codling moth, populations can increase from low numbers to severely damaging numbers within a single season without control measures. In cooler areas, supporting fewer generations, this build up is slower.
Organic controls can be effective although you need to be vigilant be sure to destroy infested fruit, remove flaking bark and broken branches along with any litter at the base of your trees and invest in a codling moth trap which are erected when the trees start to flower until the end of December-Kits are available at Harmony Garden Centre from under $30 www.harmonygc.com.au/shop-online/organic-gardening/codling-moth-trap-delta these traps used in conjunction with Yates success ultra-insecticide have proven to be successful less toxic integrated pest management controls
Did you know? One Codling moth larvae can feed on more than one apple and you may have heard people recommend using cardboard wrap around the stem of trees? The main damage to your fruit is already done as the larvae have feasted on your apples prior to finding a place around the tree to pupate. This cardboard wrap method is however beneficial in reducing any Codling moth for the following year