There really is nothing worse than sinking your teeth into an apple to find that you have a mouthful of delicious fruit and also a mouthful of ‘maggot’, maggot droppings and general gunge or sometimes just the last two without the ‘maggot’ itself. Grim either way!! As the apple harvesting season gets underway it has to be time to explain what it is all about … Codling moth caterpillars are the most commonly found ‘maggot’ in apples. It can be hard to spot because the outside of the fruit is usually in fairly good shape and the only external damage is a reddish brown area on the skin .
The whitish caterpillar has a brownish head and caterpillar stays feeding within the fruit, creating a tunnel filled full of frass (droppings) and then, once fully-fed it leaves the fruit via an exit hole which is usually clearly visible on the fruit’s surface. So sometimes you get the critter and sometimes it has already left!
So what can you do? Next year you could try using a pheromone trap to catch the male moths as these traps help to reduce the number of males sufficiently that mating is reduced and so the number of caterpillars is also reduced. So how do they work? The products used in codling moth or similar traps are, in fact, synthetic or man made versions of the insect pheromones and these act as sexual attractants, luring the male insect into the codling moth trap in the belief that it contains female moths. The males are then trapped on a sticky surface within the trap The pheromones are normally impregnated into a small rubber pellet which releases them gradually. In mid-summer, or even now as we are having warm weather, it is also worth loosely wrapping the trunk of the tree with hessian – the hope being that the caterpillars, having left the fruits, use this as a place to overwinter and then in late autumn you can remove and burn the hessian so drastically further reducing the number of caterpillars which successfully overwinter.