EPPO Platform
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Pest categorisation of Thecodiplosis japonensis

Description

The EFSA Panel on Plant Health performed a pest categorisation of Thecodiplosis japonensis (Diptera: Cecidomyiidae) for the EU territory. This species is not included in the EU Commission Implementing Regulation 2019/2072. Tjaponensis Uchida & Inouye is a well-defined species, native to a large part of Japan, which was introduced to the Republic of Korea and eastern China: Fujian and Shandong. It attacks Pinus densifloraPthunbergii and Pluchuensis in Japan; Pdensiflora and Pthunbergii in Korea; and Pmassoniana in China, and has been observed to attack other two-needle pine species, including species present in the EU. The pest is univoltine and the adults emerge between May and August. The adults live only for 1 day. Each female oviposits in batches on developing needles. The neonate larvae crawl to the base of the needle fascicle and create a gall in which they feed gregariously by sap sucking. The third-instar larvae leave the galls in November, overwinter in a cocoon in the soil and pupate at the end of the winter. Degree day models have been developed to predict adult emergence. Survival of overwintering stages is poor below 15°C and above 30°C. The pest can be detected by its symptoms (stunted or dead needles, galls at the base of infected needle fascicles), and identified using morphological characters or the mitochondrial COI gene. Tjaponensis is one of the major forest pests in the Republic of Korea, where 1.7 million trees were cut to control it in 2014–2015. It flies uneasily (a few hundred metres) but can be transported in galls on Pinus plants for planting, including artificially dwarfed plants, or with cut branches. Climate matching and host tree distribution suggest that Tjaponensis would be able to establish and have an impact in the EU territory. Tjaponensis satisfies all the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

Organisms

  • Thecodiplosis japonensis

Hosts

  • Pinus coulteri
  • Pinus densiflora
  • Pinus kesiya var. kesiya
  • Pinus luchuensis
  • Pinus massoniana
  • Pinus mugo
  • Pinus nigra
  • Pinus nigra subsp. laricio
  • Pinus radiata
  • Pinus resinosa
  • Pinus sylvestris
  • Pinus tabuliformis
  • Pinus taiwanensis
  • Pinus thunbergii

Files

Type File Size
Pest Risk Analysis Link to file

PRA Area

  • EU
  • Austria
  • Belgium
  • Bulgaria
  • Croatia
  • Cyprus
  • Czech Republic
  • Denmark
  • Estonia
  • Finland
  • France
  • Germany
  • Greece
  • Hungary
  • Ireland
  • Italy
  • Latvia
  • Lithuania
  • Luxembourg
  • Malta
  • Netherlands
  • Poland
  • Portugal
  • Romania
  • Slovakia
  • Slovenia
  • Spain
  • Sweden