Pseudips mexicanus (Coleoptera: Curculionidae: Scolytinae): addition to the EPPO Alert List
Why: Pseudips mexicanus (Coleoptera: Curculionidae: Scolytinae - Monterey pine engraver) is a North and Central American bark beetle of pine trees. It was recently recorded for the first time out of its native range: it was trapped in Ireland (EPPO RS 2024/004) and intercepted in trade in China. Considering these recent findings in different parts of the world, the EPPO Secretariat considered that P. mexicanus could usefully be added to the EPPO Alert List.
Where: P. mexicanus originates in the western part of North and Central America.
EPPO Region: Ireland (only trapped).
North America: Canada (Alberta, British Columbia), Mexico, United States of America (Alaska, Arizona, California, Colorado, Idaho, Montana, Oregon, Utah, Washington, Wyoming).
Central America: Guatemala.
On which plants: P. mexicanus has been recorded attacking a wide range of pine tree species (Pinus spp.) in its native region, including some species that are widely planted in the EPPO region such as P. ponderosa.
Damage: P. mexicanus is a bark beetle. Damage is due to the galleries under the bark where the pest reproduces, and larvae develop. Reddish sawdust can be observed at the surface of the bark.
P. mexicanus is mainly reported to infest weakened trees but can also be a primary pest causing death of small to medium size trees. In California (US), it has been shown to transmit Fusarium subglutinans, causing pitch canker. P. mexicanus has one generation per year in Canada, 3 in California and up to 7 in Mexico. Adults are 3.5 to 5 mm long, bright dark brown. There are 4 larval stages. The species can overwinter in both larval and adult stages.
Pictures of P. mexicanus are available at https://gd.eppo.int/taxon/IPSXRA/photos
Dissemination: Flight of adults is probably the main means of movement and dispersal to new plants and new areas over short distances but specific data on flying distance is lacking. Over long distances, P. mexicanus can be transported on plant material.
Pathways: Host plants for planting, wood, wood chips, wood packaging material, bark. P. mexicanus has been intercepted in trade on wood in China and in the USA. It may be noted that in many EPPO countries (including the EU) requirements already apply to relevant commodities (e.g. prohibition of import of conifer wood and plants for planting over 3 m in height, originating from non-European countries).
Possible risks: P. mexicanus can attack a wide range of pine species that are widely planted in the EPPO region, though attacks on native European pines have not yet been documented. P. mexicanus occurs in a wide range of climates and is likely to be able to establish in the EPPO region.
Sources
Atkinson T (2024) Bark and ambrosia beetles of the Americas. Available online: https://www.barkbeetles.info/index.php
Cibrián Tovar D, Méndez Montiel JT, Campos Bolaños R, Yates HO, Flores Lara J (1995) Forest insects of Mexico. Universidad Autónoma Chapingo, Chapingo, Mexico, pp. 302-303.
Fox JW, Wood DL, Koehler CS, O’keefe ST (1991) Engraver beetles (Scolytidae: Ips species) as vectors of the pitch canker fungus, Fusarium subglutinans. The Canadian Entomologist 123(6), 1355-1367.
Haack RA, Rabaglia RJ (2013) Exotic bark and ambrosia beetles in the USA: potential and current invaders. In Potential invasive pests of agricultural crops 2013 (pp. 48-74).
Pan J, Li Y, Shao P, Chen Y, Fu M, Zhu H, An Y (2022) An important insect of the genus Pseudips: Pseudips mexicanus Hopkins. Plant Diseases and Pests 13(5), 19-24.
Smith GD, Carroll AL, Lindgren BS (2009) Life history of a secondary bark beetle, Pseudips mexicanus (Coleoptera: Curculionidae: Scolytinae), in lodgepole pine in British Columbia. The Canadian Entomologist 141(1),56-69.