Life cycle (Light brown apple moth)

  • There are at least two generations per annum in the UK.
  • Larval development has 5-6 instar stages.
  • Adults can fly between February and Dec, although April to October is more usual.
  • The first generation larvae occur on fruit and leaves in June-July and the second generation larvae over-winter, probably in leaf litter.
  • It is expected that more generations will occur in the UK with climate change.
  • The first generation of moths emerge at the beginning of April from over-wintered larvae and the second generation at the end of July.
  • Eggs are laid in batches on the foliage. These hatch in 2-3 weeks depending on temperature (see ‘Monitoring' and 'Forecasting').
  • Larvae pupate when fully fed, normally in early May and early June.
  • Cool and wet weather conditions at the time of moth flight and/or during egg-hatch limit population increase.
  • The tiny first instar larvae spin webs of silk, usually on the undersides of leaves, often at a junction between the main and a side vein, and begin to feed.
  • Later they may feed on the surface of the fruits or in the calyx cavities of fruits.
  • Normally, the rate of larval development is slowed considerably during the winter; thus the majority of larvae over-winter in the prolonged early juvenile phases of the second, third, and fourth instars.
  • During this period they normally feed on herbaceous plants. Re-invasion of apple trees takes place from the beginning of April.