13th USDA Interagency Research Forum on gypsy moth and other invasive species
The EPPO Secretariat participated to the 13th USDA Interagency Research Forum on gypsy moth and other invasive species in Annapolis, Maryland, USA, 2002-01-15/18. Many papers were presented during this conference, interesting and new information has been summarized below:
Anoplophora glabripennis (Coleoptera: Cerambycidae – EPPO A1 quarantine pest)
Situation in Austria
Dr H. Krehan presented the situation of A. glabripennis in Austria. The pest has recently been found in Branau-am-Inn, during summer 2001 (see EPPO RS 2001/135). The pest was probably introduced on wood packing material from Asia, as the outbreak was located near a market place where various imported products from China were sold. The first suspect symptoms were in fact already seen in November 2000, but the city gardeners could not identify the cause as no beetles were found at that time. In July 2001, symptoms were seen on trees (mainly Acer platanoides) growing along a small street, and on 2 other trees in a small forest (less than 1 km away from the street concerned). In December 2001, one infested tree was also found in the centre of Branau am Inn. All infested trees were destroyed and phytosanitary action is being taken to prevent any further spread. Surveys will continue, in the infested zone and its surroundings, but also in other places in Austria.
Situation in USA
Surveys on A. glabripennis are continuing in USA. So far, infestations remain limited to Chicago and New York. No new major findings were made, as all new findings were still made within quarantine areas. In addition, the number of findings is diminishing. Intense research activity is continuing both in the USA and in China, on biological and chemical control, host range, behaviour, models to predict potential damage and spread, impact of the pest on urban forests, etc.
Anoplophora malasiaca/chinensis (Coleoptera: Cerambycidae – EPPO A1 quarantine pest)
Anoplophora chinensis in Washington state, US
Dr D. Lance explained that during summer 2001, Anoplophora chinensis was found in a nursery, at Tukwila, Washington state. One adult was found in a bonsai nursery importing plants from Korea. Following this first observation, 369 Acer bonsais were inspected, and 3 more adults were found (of which one flew away and was not found again). Based on examination of host material, 5 beetles are assumed to have escaped from the nursery. In another nursery in Tacoma, Washington state, 2 exit holes were observed. During an inspection of a nursery in Lacey, Washington state, one beetle was found and identified as A. chinensis (Washington state Department of Agriculture). Inspectors found 3 tunnels and 2 exit holes on 7 Acer bonsais imported from Korea. For these 2 nurseries, unlike the situation in Tukwila, it is not considered that A. chinensis could be present in the environment and multiply. All infested plant material has been destroyed. In the Tukwila area, quarantine has been imposed and surveys will be carried out for several years. It can also be recalled that A. chinensis had been found on bonsai Lagerstroemia from China, in 1999, in one glasshouse in Athens, Georgia, and that A. malasiaca had been found on Acer bonsais in a nursery in Wisconsin (USDA-APHIS Pest Alert); in both cases eradication measures were successful.
Anoplophora malasiaca in Italy
Dr Maspero presented the current situation of A. malasiaca in Italy. The pest was found in spring 2000 in Parabiago, near Milano, Lombardia (see EPPO RS 2001/101), in a nursery which imports large quantities of bonsais from Asia in containers. In June and July, 4 adults (2 males and 2 females) were found. In fact, A. malasiaca had been caught by a student in 1997 from the same area and put into a collection, without any further notice. Following the 2000 finding, traps were placed in 2 fields of the nursery where large trees were growing. A. malasiaca was found on Acer and Fagus. In the vicinity of the nursery, insects were also found on various trees (Acer saccharinum, Carpinus betulus, Fagus, etc.). Larvae, galleries and exit holes were found on infested trees and some trees had even been re-infested. This clearly shows that A. malasiaca is well established in the nursery and its surroundings. As a result, 18 trees have been destroyed and during the 2001/2002 winter more trees will be destroyed. Treatment and extensive survey programmes will be set up. Information for the public and the growers will be provided.
Ophiostoma ulmi and O. novo-ulmi (Dutch elm disease)
Dr C. Brasier presented research work which showed that exchange of genetic material took place between the two species Ophiostoma ulmi and O. novo-ulmi, and that they are fully hybridizing. Considering the Phytophthora disease of alder, it is also hypothetised that the causal agent is a hybrid between P. cambivora and P. fragariae. However, this remains to be demonstrated.
Phytophthora ramorum (sudden oak death – EPPO Alert List)
Dr D. Rizzo presented the latest information available on P. ramorum. It is now clear that the pathogen killing oaks in California and the pathogen found on Rhododendron and Viburnum in Europe are the same. Early comparisons between the American and European pathogens have showed that they belong to two separate populations, both probably introduced from a third unknown place. Studies on host plants showed that Lithocarpus densiflorus (tan oak) is the most susceptible species, as all plant parts (roots, trunk, branches, twigs and leaves) can be affected. On Quercus agrifolia, Q. kelloggii, Q. parvula var. shrevei, infection is only seen on trunk and main branches. On the other host plants (Acer macrophyllus, Aesculus californica, Arbutus menziesii, Arctostaphylos manzanita, Heteromeles arbutifolia, Lonicera hispidula, Rhamnus californica, Umbellularia californica, Vaccinium ovatum), P. ramorum is essentially affecting leaves, petioles and stems, and no mortality is observed. White oaks are not susceptible to P. ramorum. There has been recent concern that redwoods (Sequoia sempervirens) might be host plants of P. ramorum, because the pathogen was identified on redwood sprouts (but not killing trees).It was stressed that the host status of S. sempervirens has not been demonstrated neither in the laboratory nor in the field, but research is continuing in this field.
Tetropium fuscum (Coleoptera: Cerambycidae)
Tetropium fuscum is a European species (secondary pest in European forests) which has recently been introduced into Canada. It was found in dying red spruce trees (Picea rubens) at Point Pleasant Park in Halifax, Nova Scotia. This amenity park of 75 ha, mainly planted with red spruce, is located near a container facility. The first beetles were in fact seen in 1990, but were misidentified until 1999. Eradication measures are being taken.
Sources
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Papers presented at the 13th USDA Interagency Research Forum on gypsy moth and other invasive species, Annapolis, Maryland, USA, 2002-01-15/18.
USDA – APHIS Pest Alert. Longhorned beetles in bonsai nursery stock
http://www.aphis.usda.gov/oa/pestaler/palbbn.html
Washington state Department of Agriculture – Citrus longhorned beetle found at a second site in Washington.
http://www.wa.gov/agr/communications/2001/news0135.htm
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