The Canadian Entomologist (2001) 133, 687-696

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D.E. Waldstein, W.H. Reissig and J.P. Nyrop (2001)
Larval movement and its potential impact on the management of the obliquebanded leafroller (Lepidoptera: Tortricidae)
The Canadian Entomologist 133 (5), 687-696
Abstract: The rate at which obliquebanded leafroller, Choristoneura rosaceana (Harris), larvae vacated feeding sites in apple, Malus domestica Borkhauser (Rosaceae), trees was determined by monitoring infested terminal foliage under field conditions. The overwintering and summer generations of C. rosaceana were monitored in two orchards in 1997 and 1998. Larvae vacated terminal feeding sites relatively frequently because 50% of the sites during the overwintering and summer generations were vacant 34 ± 6 °d (threshold = 6 °C) and 53 ± 10°d, respectively, after sites had been marked. Vacancy rates increased from the beginning to the end of the summer generation in 1997 but remained relatively constant throughout the summer generation in 1998. The differences between the 2 years were probably because of less precipitation and lower availability of actively growing terminal foliage at the end of the summer in 1997 than in 1998. Differences in larval development did not seem to contribute to differences in vacancy rate. Recolonization of growing terminals was also studied in the field by removing C. rosaceana larvae from terminals only (1997) and the entire tree (1998). In 1997 and 1998, larval recolonization of terminals and trees occurred, because 6-8 d after larvae were removed populations in removal and adjacent control trees were not significantly different. Frequent larval movement to actively growing terminal foliage with sublethal insecticide residues may increase larval survival and could slow resistance development by providing a refuge for susceptible insects.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Daniel E. Waldstein, Jan P. Nyrop

Research topic(s) for pests/diseases/weeds:
population dynamics/ epidemiology
environment - cropping system/rotation

Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.

Choristoneura rosaceana Apple (Malus)