Use pheromone traps placed in May (details below), so if necessary action can be taken before a damaging infestation has developed. When choosing control options you can minimise harm to non-target animals by starting with the methods in the non-pesticide control section. If this is not sufficient to reduce the damage to acceptable levels then you may choose to use pesticides. Within this group the shorter persistence pesticides (that are usually certified for organic growing) are likely to be less damaging to non-target wildlife than those with longer persistence and/or systemic action.
- Where possible tolerate the loss of some fruit to plum moth, often only a small proportion of fruits are affected. At first levels of the moth can seem high as the first fruit to ripen are those that have been affected by caterpillars
- Encourage predators and other natural enemies in the garden such as birds, hedgehogs and ground beetles
- Pheromone traps can be used to trap male moths. They use a synthetic version of volatile chemical (sex-pheromone) produced by female moths to lure in males
- Pheromone traps for plum moth are available from garden shops or from some mail order suppliers of pest controls or biological pest controls. These consist of an open-sided box that is hung in the tree in early May. The bottom of the box has a sticky sheet on which the pheromone pellet is placed. Male plum moths are lured into the trap and get stuck
- These traps alone rarely control plum moth but monitor moth activity. This can improve control by indicating if a pesticide spray is worthwhile and can help accurately time pesticide use if deemed necessary
- On isolated trees these traps may catch enough males to reduce the females' mating success, resulting in fewer fertile eggs being laid
- By counting the trapped males every week and following the instructions that come with the trap, the best time to spray can be calculated
- Pheromone traps are designed to prevent birds entering the trap and getting caught on the sticky sheet, although occasionally birds can enter the traps and it may be necessary to add additional bird netting
Pesticide treatment is only possible and worthwhile on small trees that can be sprayed thoroughly
- Plum moth caterpillars can only be controlled on apple and pear with insecticides before they enter the fruits
- Organic contact insecticides containing natural pyrethrins (e.g. Bug Clear Gun for Fruit & Veg, Neudorff Bug Free Bug and Larvae Killer). Several applications of these short persistence products may be necessary to give good control
- More persistent contact insecticides include the synthetic pyrethroids lambda-cyhalothrin (e.g. Westland Resolva Bug Killer), deltamethrin (e.g. Provanto Ultimate Fruit & Vegetable Bug Killer, Provanto Sprayday Greenfly Killer) and cypermethrin (e.g. Py Bug Killer)
- Timing of spray can be more accurately determined by the use of a pheromone trap (see above) otherwise a spray in about the third week of June, with a second application about three weeks later may have some effect. In some years, egg hatching may be earlier or later, due to the weather conditions and in years with long summers there may be two generations of the moth
Follow label instructions when using pesticides. On edible plants make sure the food plant is listed on the label and follow instructions on maximum number applications, spray interval and harvest interval.
Plants in flower should not be sprayed due to the danger to bees and other pollinating insects.
Inclusion of a pesticide product does not indicate a recommendation or endorsement by RHS Gardening Advice. It is a list of products currently available to the home gardener.
Pesticides for gardeners (pdf document)