Brownheaded leafrollers - Life history

Most of the brownheaded leafroller population spends the winter as young (2nd to 4th stage) caterpillars on ground cover plants, on fallen leaves, in fruit buds, or occasionally under the bark. There is no true dormancy and the caterpillars feed on warm winter days. The caterpillars complete their development, spin a loose silken cocoon, and change to pupae in the spring and early summer before emerging as adult moths. In southern areas with two generations per year, emergence begins in mid November and is spread over December and into January. Males emerge a short time ahead of females. The second generation emerges from February to May. In northern areas, the emergence of the overwintered generation is completed by December, the second generation of adults occurs over January/early March, and overlapping third or partial fourth generations occurs through to July. However, all stages are present at most times in the north making it difficult to distinguish generations. Females are normally mated only once and egg laying usually begins on the following day, reaching a peak after a few days. They mature and lay a series of egg batches on the upper surface of leaves during their lifetimes, which is about 3-4 weeks at 20^oC. The caterpillars hatch within 1-2 weeks and disperse to settle on the lower surfaces of leaves, often against the midrib and main veins. As the caterpillar grows, it moves to new sites, such as between two leaves, between leaf and fruit, or within a roll created by folding the edge of a leaf. Larval development is completed on apple leaves in about 30 days at 20^oC (Ctenopseustis obliquana). Prior to pupation, the majority of larvae leave their feeding sites and prepare new rolls or spin up specially for pupation and emergence. The threshold temperature for development has been determined as 4.8^oC.

This life history is summarised in the life cycle charts.