Importation of Dwarf Juniper Trees from Japan
Importation of Dwarf (Bonsai) Juniper Trees from Japan
The entry of a number of consignments of bonsai Juniperus chinensis exported to the United Kingdom from Japan has been recently refused.
The trees from all traced consignments were inspected and a substantial number were found to be infected with the rust Gymnosporangium asiaticum which appears not to have been reported from Europe. This rust affects Juniperus chinensis and J. procumbens, and its known alternative hosts are various species of Pyrus, Cydonia, Chaenomeles and Photinia (Eriobotrya). Appropriate action has been taken on the infected consignments.
In infection studies under strict quarantine, spermogonia have so far been obtained on Pyrus communis (variety Conference and unnamed seedlings), P. betulifolia, P. pyrifolia and appear to be developing on Chaenomeles japonica.
In addition, some of the trees were infested with gall midge (Aschistonyx eppoi Inouye). The gall midge has been found on several consignments of J. chinensis in 1974, and was previously found in 1973. There is evidence that it survived on some premises during the period.
On one consignment, a very light infestation of a false red spider mite (Acari : Tenuipalpidae) was observed. The species is Pentamerismus oregonensis McGregor. The only records are for J. chinensis. It has been recorded as far north in Japan as Hokkaido. It has also been intercepted in the United States of America on junipers imported from Japan. There is no information on its biology.
The attention of the Japanese plant protection service has been drawn to these incidents.
Ministry of Agriculture, London (1974-08-20)