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).
Control
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 using an autoconfusion system.
Now that the codling moth granulovirus (Carpovirusine, Cyd-X, Madex Top) 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 ten sprays each (Madex Top) giving 8-14 days protection is allowed per season (a maximum of six sprays per generation)
- Application should be made just before egg hatch is expected to ensure larvae pick up virus particles as they move from the egg to the apple entry point. Application a little bit too early is preferable to a little bit too late.
- 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 applied at or shortly before the onset of egg laying, or indoxacarb (Steward or Explicit), or spinosad (Tracer) applied at the onset of egg hatch.
- Pyriproxyfen (Harpun) can also be used as an alternative which is first applied up to 24 hours after egg laying. It inhibits egg hatch. It can also be applied later to inhibit metamorphosis of nymphs to adults. It also reduces the fecundity of adult females.
- 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.
Sex pheromone mating disruption
RAK 3+4 is a combined pheromone control system which reduces fruit damage from codling moth (RAK 3) and summer fruit tortrix (RAK 4). Both pheromones disrupt mating behaviour and therefore prevent populations from developing. The pheromones are released from sealed chambers by volatilisation, preventing male and female moths from locating each other and reproducing.
- RAK 3+4 is most effective in orchards with a low pest population density. It should not be used in orchards where more than 1% of fruits (including fallen fruits) were damaged by codling and tortrix moths in the preceding year, unless the first generation of moths is treated with a control product to reduce initial populations.
- In AHDB Project TF 223 (Improving integrated pest and disease management in tree fruit), RAK 3+4 provided similar control of codling, fruit tree tortrix and summer fruit tortrix moths when compared to conventional spray programmes in field trials. It did not provide complete control and it may be necessary to employ additional sprays should monitoring trap catches of moth pests exceed damage thresholds, especially in early ripening apples and pears, which are more vulnerable.
- Best results are achieved in isolated orchards, i.e. those which are 100 m or more away from other orchards or high trees.
- Optimum results are also achieved in grouped orchards containing trees of similar size and shape.
- RAK 3+4 will not be effective if there is a high density of codling moth and/or tortrix moth in the area adjacent to the orchard being treated. It will not be effective in orchards less than 1 ha in area.
- RAK 3+4 is specific to codling and tortrix moths. Other moth pests such as Blastobasis lacticollela can increase in population where other lepidoptera control agents are not being used.
- Further details on time of application, dose and positioning of dispensers.
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 interval between sprays (days) |
| adoxophyes orana granulovirus | Capex | microbial biocontrol | highly selective | sft | safe | none stipulated |
| Bacillus thuringiensis var. kurstaki | Dipel DF | bacterial | selective | c | safe | 7 |
| chlorantraniliprole | Coragen | anthranilic diamide | selective | c | safe | 14 |
| E8, E10-dodecadienol, Z11-tetradecenylacetate, n-tetradecylacetate | RAK 3+4 | sex pheromone mating disruption | highly selective | cm, sft | safe | none stipulated |
| codling moth granulovirus | Carpovirusine, Cyd-X, Madex Top | microbial biocontrol | highly selective | cm | safe | 8 sunny days |
| deltamethrin | Decis Forte etc | pyrethroid | broad spectrum | c, cm, t | harmful | none stipulated |
| indoxacarb | Steward, Explicit | oxadiazine | selective | c, cm, ftt, sft, wm | u | varies with product |
| pyriproxyfen | Harpun | metamorphosis inhibitor | selective | cm | safe | none stipulated |
| 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 zone width (m) | ||||
| Anticholin-esterase? | Humans | Fish & aquatic life | Bees | ||||
| adoxophyes orana granulovirus | no | u | u | u | 0 | u | 0 |
| Bacillus thuringiensis var. kurstaki | no | u | u | u | Varies with product | Varies with product | 5 |
| chlorantraniliprole | no | h | ed | h | 14 | 2 | 10 |
| E8, E10-dodecadienol, Z11-tetradecenylacetate, n-tetradecylacetate | no | u | t | u | None stipulated | 1 | u |
| codling moth granulovirus | no | h,i | u | u | Varies with product | Varies with product | 0 |
| deltamethrin | no | h,i | ed | d | 7 | u | 50 |
| indoxacarb | no | h | ed | u | 7 | 3 | 15 |
| pyriproxyfen | no | d | t | u | fruit diameter up to 40mm | 2 | 20 |
| spinosad | no | u | ed | h | 7 | 4 | 40 |
| 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, wm=winter moth 3d=dangerous, ed=extremely dangerous, h=harmful, ir=irritant, t=toxic u=no hazard specified | |||||||
Control in organic orchards
Organic growers should use multiple codling moth granulovirus sprays (up to 6 applications per generation and not exceeding 10 applications per season for Madex Top) and in combination with season-long maintenance of a pheromone autoconfusion system.
- Note that Bacillus thuringiensis has little effect on codling moth.
- Cultural control remains an important additional measure.