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Summer fruit tortrix moth (Adoxophyes orana Fischer von Röslerstamm)

Summer fruit tortrix adults Male (left) Female (right)

Summer fruit tortrix egg batch on leaf

Summer fruit tortrix larva

Small holes in fruit caused by larvae

Fruit damage

Summer fruit tortrix leaf roll

The summer fruit tortrix moth is an important secondary pest of apples and pears, especially in eastern and south-eastern England. The life cycle involves two generations a year in the UK.

Short stalked varieties such as Bramley and Discovery are most susceptible, but all varieties of apple and pear may be attacked.

Damage to foliage is unimportant but damage to fruits occurs at three different times during fruit development.

Larvae of several leaf-rolling tortrix moths are very similar and are difficult to distinguish  from each other. The pest should be monitored with pheromone traps weekly from petal fall of apple to the end of August.

The need to treat for the pest should be determined by high trap catches (>30 moths per trap per week) or damage the previous season, or by the presence of high populations of caterpillars in blossom trusses in spring before bloom.

Control  

Various insecticides that are approved for control of colding moth, totrix moths or for general caterpillar control are likely to control summer fruit tortrix moth.

  • The pest may be controlled with indoxacarb (Steward), methoxyfenozide (Runner), spinosad (Tracer) or with Bacillus thuringiensis, applied to coincide with egg hatch usually in June.
  • Bacillus thuringiensis is considered to be of only moderate efficacy. The first spray should be applied at the onset of egg hatch of the first generation.  Further sprays should be applied at 7-10 day intervals until the egg hatch period has ended.
  • Synthetic pyrethroids are highly effective but their use should be avoided as they are harmful to predatory mites and other beneficial insects.
  • Chlorantraniliprole (Coragen) is also thought to offer incidental control when applied against codling moth.
  • The summer fruit tortrix ganulovirus (Capex) is another option. Highly specific to summer fruit tortrix, it is ideal for use in organic and IPM production systems and has no harvest interval or buffer zone requirement.
  • The onset of egg laying is taken as the date when the pheromone trap catch exceeds 5 moths/trap/week. If traps are only examined weekly, the date when this occurred can often be pin-pointed more accurately by examination of daily temperature records.
  • The moths fly when dusk temperatures exceed 15 °C. The onset of the egg hatching period occurs 7-21 days later, depending on temperature. It can be accurately forecast from daily maximum and minimum air temperatures using the look-up table provided.
  • The daily percentage egg development amounts are summed from the date of the onset of egg laying. When the sum reaches 90%, egg hatch is imminent and the first spray should be applied.
  • A second generation occurs in August and September which can be damaging on later harvested varieties. The second generation may be controlled in the same way.

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.
  • 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.
  • Further details on time of application, dose and positioning of dispensers.

Insecticides approved on apple for control of codling, tortrix moths or caterpillars on apple which are likely to control summer fruit tortrix moth or offer incidental control when applied to control other pests

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
Bacillus thuringiensis var. kurstaki Dipel DF bacterialinsecticide selective to caterpillars c safe 7
chlorantraniliprole Coragen anthranilic diamide selective c safe 14
deltamethrin Decis pyrethroid broad spectrum cm, t harmful none stipulated
E8, E10-dodecadienol, Z11-tetradecenylacteate, n-tetradecylacetate RAK 3+4 sex pheromone mating disruption highly selective cm, sft safe none stipulated
indoxacarb Steward oxadiazine selective c, cm, ftt, sft u 10
methoxyfenozide Runner MAC selective c safe u
spinosad Tracer neural blocker selective C, cm, ftt,sft safe u

Choice of insecticides – Safety factor

Read and and follow the label before applying any sprays

Hazards2 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
Bacillus thuringiensis no u u u Varies with product Varies with product 5
chlorantraniliprole no h ed h 14 2 10
deltamethrin no h, i ed d 7 u 50
E8, E10-dodecadienol, Z11-tetradecenylacteate, n-tetradecylacetate no u t u None stipulated 1 u
indoxacarb no h ed u 7 3 15
methoxyfenozide no u u u 14 3 5
spinosad no u ed u 7 4 40
Keys:    1CSI=chitin synthesis inhibitor, JHA=juvenile hormone analogue2c=caterpillars, cm=codling moth, ftt=fruit tree tortrix, sft=summer fruit tortrix,  t=tortrix

3d=dangerous, ed=extremely dangerous, h=harmful, i=irritant,  t=toxic, u=no hazard specified

 

Control in organic orchards

Summer fruit tortrix moth should be less problematic in organic orchards because populations are regulated by natural enemies, especially parasitic wasps and probably also because tree vigour is lower in organic orchards (see ‘Cultural control’).

  • If control measures are necessary, sprays of Bacillus thuringiensis or spinosad (Tracer), should be applied in the same way as in conventional orchards (see above).
  • In addition, the granulovirus (Capex) that is available to control summer fruit tortrix is highly specific to this pest. It is ingested by larval feeding. The larvae subsequently die and break down. Capex is ideal for use in organic and IPM systems of production. Approval should always be sought from organic certification bodies before use in organic production systems.

 

 Further reading