Evaluation of reflective groundcovers for pest and fruit quality management in commercial pear orchards

Reflective groundcovers can improve crop yield and quality and deter pests by increasing light penetration into plant canopies. In pear (Pyrus communis L.) orchards, this could increase profitability and reduce reliance on insecticides to manage pear psylla (Cacopsylla pyricola [Foerster]). Two types of reflective groundcovers, metallized polyethylene film (metallized film) and white geotextile fabric (reflective fabric), are known to increase pear yield and quality, and metallized film was recently reported to suppress pear psylla. Here, we tested reflective fabric for pear psylla suppression at a research orchard in 2019, then we partnered with five pear orchard managers to test metallized film and reflective fabric for pear psylla suppression at five conventional commercial orchards in 2020 and one organic commercial orchard in 2021. There was evidence of pear psylla suppression by both metallized film and reflective fabric, but effects varied among reflective materials, pear psylla life stages, season and year of study. Reflective groundcovers did not affect fruit size, weight, sunburn or pest mite abundance, and they were compatible with pear psylla biocontrol. Low perceived benefit relative to cost was a barrier to continued trialling and adoption. Whereas orchardists in our study used reflective groundcovers in addition to normal pesticide regimes, previous research studies suggest that reflective groundcovers can profitably replace some insecticides. Future studies are needed to test the outcomes of replacing pesticides with reflective groundcovers in commercial orchards and understand under what circumstances they improve pear quality and yield.