Pest Activity and Protection Practices: Four Decades of Transformation in Quebec Apple Orchards.

A group of commercial orchards from Quebec (Canada) was followed from 1977 to 2019 as part of a project to implement Integrated Pest Management (IPM) practices. Collected data comprised activity of major fruit pests (from monitoring traps), fruit damage at harvest and pesticide applications, from which the annual costs and impacts of protection programs over 42 years were calculated. Activity and fruit damage in commercial orchards were compared to patterns observed in a reference insecticide-free orchard. Some insects (European apple sawfly, codling moth, apple maggot) were more prevalent in the insecticide-free orchard than in commercial orchards, while others were more prevalent in commercial orchards (oblique-banded leafroller) or as prevalent in both orchard types (tarnished plant bug). Annual fruit damage in the insecticide-free orchard was mostly from the apple maggot (up to 98%), the plum curculio (up to 90%) and the codling moth (up to 58%). The average situation was different in commercial orchards, whose damage was mostly from the plum curculio (up to 7.6%), the tarnished plant bug (up to 7.5%) and the oblique-banded leafroller (up to 1.7%). While the number of registered pesticides, the number of applications and the total cost of pesticides gradually increased from 2002 to 2019, the risks incurred, as measured by indicators of environmental and health impacts, followed a downward trend for insecticides and acaricides and varied slightly for fungicides.