Codling moth (Cydia pomonella L.)
Adult codling moth
Codling moth egg
Codling moth larva in fruit
Codling moth entrance hole in fruit (‘sting’ injury)
Codling moth is a key pest of apple, which attacks the fruit directly causing economic damage at low population densities. It is sometimes very damaging to pear.
The life cycle involves one complete and one partial generation per year in southern Britain, though two generations occur in hot summers.
First generation adults emerge in May to July and fly at dusk on warm evenings. Eggs are laid singly on leaves and the surface of fruits. Larvae hatch after 7 10 days, depending on temperature, and cause damage by boring into the flesh of the fruit. A characteristic entrance hole is left, partially blocked by dry frass.
This readily recognised pest should be monitored using pheromone traps, monitored weekly from petal fall until harvest. The threshold is a single catch of 5 or more moths per trap per week from May to June (first generation, fruit less susceptible) and 3 per trap per week from August to Setpember (second generation, fruit more susceptible).
In addition to sanitation measures which help reduce the worst ravages of attack, there are three different approaches for controlling codling moth:
- biological control with sprays of the codling moth granulovirus
- chemical control with sprays of insecticides which are either ovicidal, larvicidal or both
- sex pheromone mating disruption with a grid of Exosex autoconfusion dispensers.
Now that the codling moth granulovirus (Cyd-X) is available, it should be used wherever possible, bearing in mind the following limitations:
- It only controls codling moth and not tortrix moths, Blastobasis or other pests
- A maximum of three sprays each giving 8-14 days protection is allowed per season
- Heavy attacks may result in some superficial sting injury as the young larvae hatching from eggs do not die immediately.
A chemical control programme should comprise a series of sprays of insecticides at 2-3 week intervals, maintaining an insecticide deposit throughout periods of risk.
- The interval between sprays should be 2 weeks if temperatures are high or if the risk is high.
- The choice of insecticides is chlorantraniliprole (Coragen), fenoxycarb (Insegar) or diflubenzuron (Dimilin) applied at or shortly before the onset of egg laying, or indoxacarb (Steward), methoxyfenozide (Runner) or spinosad (Tracer) applied at the onset of egg hatch.
- Use of synthetic pyrethroid insecticides, which are very effective, should be avoided as they are harmful to predatory mites and many other important natural enemies.
- The onset of egg laying is when a threshold pheromone trap catch is exceeded.
- Egg hatch occurs 7-10 days later.
- The interval between egg laying and egg hatch can be estimated more precisely by accumulating percentage egg development amounts calculated from daily maximum and minimum air temperature.
- First egg hatch is expected when the accumulated sum reaches 100%.
- Be vigilant for second generation attacks, which occur in August in hot summers.
The Exosex CM codling moth pheromone autoconfusion system provides another codling moth control option.
- A lattice of 25 delta dispensers per ha is set out in a grid through the orchards at the start of the codling moth flight in May, as indicated by sex pheromone trap catches.
- Each dispenser contains wax powder loaded with the codling moth sex pheromone in its base and a sex pheromone lure.
- The lure attracts males into the dispensers where they become contaminated with the pheromone-loaded powder which is attracted electrostatically to their bodies.
- Contaminated males are confused and also attract other males so preventing or delaying mating of females.
- Like other sex pheromone mating disruption systems, it only gives adequate control of low codling moth populations and should be used in combination with other codling moth control measures including granulovirus and/or insecticides.
Products approved for control of codling, tortrix moths or caterpillars on apple
Choice of insecticides – efficacy factors
|Active ingredient||Trade name (examples)||Class1||Selectivity||Label rec’s2||Safety to Typhs||Suggested intervalbetweensprays(days)|
|adoxophyes orana granulovirus||Capex||microbial biocontrol||highly selective||sft||safe||u|
|(E,E)-8,10-dedecadien-1-ol||Exosex CM||sex pheromone mating disruption||highly selective||cm||safe||none stipulated|
|codling moth granulovirus||Cyd-X||microbial biocontrol||highly selective||cm||safe||none stipulated|
|deltamethrin||Decis||pyrethroid||broad spectrum||cm, t||harmful||none stipulated|
|diflubenzuron||Dimilin||CSI||selective||c, cm, ftt||safe||none stipulated|
|indoxacarb||Steward||oxadiazine||selective||c, cm, ftt, sft||u||10|
|spinosad||Tracer||neural blocker||selective||C, cm, ftt,sft||safe||u|
Choice of insecticides – Safety factors
Read and follow the label before applying any sprays
|Hazards3||Harvest interval(days)||Max. no. sprays||Buffer zoneWidth (m)|
|Anticholin-esterase?||Humans||Fish & aquatic life||Bees|
|adoxophyes orana granulovirus||no||u||u||u||0||u||0|
|codling moth granulovirus||no||h,i||u||u||None stipulated||3||u|
|Keys: 1CSI=chitin synthesis inhibitor, JHA=juvenile hormone analogue MAC= moulting accelerating compound 2c=caterpillars, cm=codling moth, ftt=fruit tree tortrix, sft=summer fruit tortrix, t=tortrix 3d=dangerous, ed=extremely dangerous, h=harmful, ir=irritant, t=toxic u=no hazard specified|
Control in organic orchards
Organic growers should use both codling moth granulovirus (Cyd-X) sprays (one or two sprays against each generation, not exceeding the maximum of 3 sprays) and in combination with season-long maintenance of Exosex pheromone autoconfusion system.
- Note that Bacillus thuringiensis has little effect on codling moth.
- Cultural control remains an important additional measure.