Management strategies for a new weevil pest in pear

We work closely with fruit growers and their agronomists to identify the appearance of new and invasive insect pests, diseases and weeds in the UK.

We were recently alerted to a new weevil pest in pear crops, which has since been identified as Anthonomus spilotus. It causes feeding damage to buds and flowers in spring and crop foliage during the growing season.

We funded research with entomologists at NIAB EMR to work with local agronomists to understand the extent of the damage and how best to manage the pest.

What damage does Anthonomus spilotus cause to pear crops?

Adult weevils were found to cause the most damage to flowers and leaf buds rather than the larvae, which burrow into the buds.

In our trials, an average of only one out of a cluster of six flowers was damaged. Given that only three to four fruits set on a single truss in the cultivar conference, this level of damage is not economically significant. However, up to 60% of new leaves can be damaged during the growing season, which would have an adverse effect on the photosynthetic ability of the tree.

How can I prevent and control Anthonomus spilotus?

You must continue to monitor for the pest in the spring and throughout the growing season. If populations increase, then implement control measures.

Our trials showed that thiacloprid (Calypso) and pyrethrins (Spruzit) offered the most effective control, but neither are approved any longer on pear. Acetamiprid (Gazelle) and lambda-cyhalothrin (Hallmark) offered 50% control. We need more extensive studies to confirm the effectiveness and best timing of the application of these products in the field to control A. spilotus and other spring damaging weevils.

Scott has worked for AHDB for 11 years, having spent three years at HDC and 30 years in the fruit industry in total. Prior to his time at AHDB, Scott was a fruit advisor/agronomist for 16 years with ADAS, specialising in soft fruit and apple and pear storage.