Pest categorisation of Oligonychus perditus

Area of Science:

• Agricultural Entomology
• Plant Pathology
• Invasive Species Risk Assessment

Background:

• Oligonychus perditus (spider mite) is a pest primarily affecting Juniperus, Chamaecyparis, and Platycladus species.
• This species is native to East Asia (China, Japan, Korea, Taiwan) and is currently absent from the European Union (EU).
• It is listed in Annex IIAI of Directive 2000/29/EC, with its host plants listed in Annex III.

Purpose of the Study:

• To perform a pest categorization of Oligonychus perditus for the EU.
• To assess its potential risk and suitability for regulation as a quarantine pest.
• To evaluate pathways, establishment potential, and impact within the EU.

Main Methods:

• Review of existing data on Oligonychus perditus biology, distribution, and host range.
• Analysis of interception records within the EU.
• Comparison with closely related and established species, such as Oligonychus ununguis.
• Assessment against criteria for quarantine pest status by the European Food Safety Authority (EFSA).

Main Results:

• Oligonychus perditus is a well-defined species, absent from the EU, with plants for planting, cut flowers, and branches identified as potential pathways.
• Despite repeated interceptions, establishment in the EU has not occurred, with one exception of a small population surviving for 8 years.
• The host range overlaps significantly with the established Oligonychus ununguis, suggesting limited additional damage if introduced.

Conclusions:

• Oligonychus perditus meets criteria for consideration as a potential quarantine pest, though uncertainties regarding impact remain.
• As the species is currently absent from the EU, it does not meet criteria for a regulated non-quarantine pest.
• Current control methods include cultural practices (sanitation) and chemical treatments (acaricides).