The small adults of the plum fruit moth (Grapholita funebrana) have dark brown forewings and brownish-grey hind wings with a metallic glow. Their wingspan is 14-15 mm. There is a light-coloured border at the outer edge of the wings. The flight of the moths takes place in twilight in warm and calm weather after the blossoming of plum trees over a period of one to two months. After the flight and mating, female moths lay eggs on young fruit. In 7-10 days, larvae hatch from the eggs and burrow into the fruit. A distinctive globule that appears like rubber is created at the entry point. The larva feeds on the fruit for 17-50 days, filling the surroundings of the seed with its excrement. The growth of the damaged fruit stops and it withers.
The adult larvae, 12-15 mm long, with pinkish-red bodies and brown heads, proceed to the tree trunks where they overwinter in cocoons under the bark and in bark cracks, and sometimes also on the ground. Adult plum fruit moth, top view and side view. Larva inside a damaged plum.

Pheromone trap for the plum fruit moth

By using 2-3 plum fruit moth pheromone traps, you will be able to identify the presence of this pest in your garden and, based on the insects caught in the traps, estimate their numbers in order to decide whether insecticide spraying is required. By using more traps (one for every tree), you will be able to reduce the numbers of this pest in your garden by catching the plum fruit moths (“trapping out”).

Assembly of the trap

The edges at the bottom of the trap are folded upwards.
The pair of gluey bases is pulled open and one gluey base is placed on the bottom, gluey side upwards.
The rubber pheromone capsule (dispenser) is placed in the centre of the gluey base.
Fasteners are pushed through the openings and used to fasten the trap to a branch.
The trap is hung as horizontally as possible on the southern or western outer branch of the tree in order to cover it from direct sunlight.
When using pheromone traps in order to monitor the plum fruit moth, the traps are hung at a height of approximately 2 metres in order to make it possible to inspect them once a week.
For monitoring purposes, the trap is opened from the side, the insects are removed from the gluey base with a spatula or the edge of a knife, and the number of plum fruit moth in the trap is registered.

If it becomes apparent in the course of the inspection that the gluey base is dusty or filled with insects and refuse, it must be replaced. If there are numerous pests in your garden – if the traps catch an average of 10 or more moths per trap in a week – it is recommended to conduct insecticide spraying and continue monitoring the numbers of the plum fruit moth in order to decide whether spraying should be repeated.

It is recommended not to conduct insecticide spraying if the number of moths caught is below the spraying criterion. This will help you preserve nature and avoid needless expenses on insecticide.
We recommend hanging more traps in the garden (trapping out) in order to avoid any further increase in the numbers of the pest.
Trapping out plum fruit moths with pheromone traps is well suited for pest control in your own garden where it is not recommended to use insecticides at all, or if required, insecticides are used as little as possible.

For the purpose of pest control, a trap must be hung on every plum tree or one for every two saplings, and the traps must definitely be hung higher – at a height of 2-3 metres – as adult plum fruit moths mainly fly in the upper third of the treetop.

After 3-4 weeks, the gluey bases of the traps have gathered plenty of dust, are covered with insects and refuse, and should certainly be replaced. If the flight of the moths lasts for a longer period (mainly depending on the weather), both the gluey base and the dispenser should be replaced in the second half of July.
If the spare capsule is not required, it can be stored in a cool place in sealed packaging and used next spring.

NB! The glue used on the base is very sticky and cannot be washed off with water. Regular petrol or white spirit may be used for cleaning hands; cooking oils and other substances are less efficient. If the weather has not excessively damaged the casing of the trap, it may be used again next year, but only for the same insect species. A noticeable decrease in the damage caused by the pest is generally achieved as the result of pest control over 2-3 years. In order to avoid a new increase in the numbers of the pest in the garden, you should continue using the traps.”