Achieving areawide IPM implementation of pear psylla, Cacopsylla pyricola), using a new phenology model, decision support tools, and collaboration with “early-adopter” growers

Pear psylla, Cacopsylla pyricola, has remained the most costly pest of Washington pears for decades. Pear psylla excrete honeydew which marks fruit and stresses trees. To control this pest, conventional pear growers in Central Washington make 15 sprays per season, costing approximately $1,500/acre. Many of these sprays poorly align with susceptible psylla life-stages, which worsens psylla and mite problems by disrupting biological control. An integrated pest management (IPM) approach using non-disruptive strategies to suppress pear psylla could save growers money and improve pest management. Unfortunately, IPM has struggled to take hold in pears due to lack of specific recommendations with consistent outcomes. In 2019, a degree day model for pear psylla was completed, and in 2021, we developed management recommendations corresponding to degree days for kaolin clay, insect growth regulators (IGRs), honeydew washing, and summer pruning. In 2022, we will begin testing the degree day program in commercial pear orchards against standard conventional programs. The degree day model, management program, methods to evaluate efficacy, and plans for implementation will be discussed.