Monitoring insect pest activity in apple orchards under codling moth sterile insect releases

An area of about 35 ha of apple orchards has been under mating disruption and sterile insect release (SIR) for controlling codling moth. This area has been subjected to intensive scouting and monitoring for pest arthropods, their damage, pathogen infection and physiological defects. During the early stages of the investigation, there was no detectable codling moth damage. However, during the second season codling moth from an outside source caused damage. It took three seasons of intensive spray applications to reduce the population to the point of no detectable damage. This intensified spraying against codling moth did not disrupt the biological control of mites or woolly apple aphid. During the course of the study it appeared as if the fruit weevil stem barriers interfered with mealybug control. When the stem barriers were in place, mealybug infestations increased, while fruit weevil damage remained low. When the stem barriers were removed, mealybug infestations declined, but fruit weevil damage increased.