NAME OF THE ORGANISM: Pseudaulacaspis pentagona (PSEAPE)

Evaluation continues

The pest is not mentioned in PM4/30 almond, apricot, peach, plum (2001), nor in PM4/9(1) Ribes (2008).
Remark: The assessment performed covers the given host species as well as interspecific hybrids with other Prunus species.

Candidate

List of pathways:
• Plant: yes
• Air: yes (wind, phoresy like with birds or insects)
• On its own: yes: first instar can crawl
Pseudaulacaspis pentagona is thermophilic species, originated in eastern Asia, and is a tropical/subtropical species that is now cosmopolitan in distribution. In colder countries, it is found only under glass. In the past 20 years it has started to spread northwards in Europe in field conditions, possibly as a result of climate change. Where 'eradication' has been reported, P. pentagona may have died out locally because of unsuitable conditions, or it may persist at low densities (Watson, 2002).
Pseudaulacaspis pentagona is polyphagous. However, it cannot complete development on some of the hosts that have been listed by various authors, which indicates that some may not be true host plants. Davidson and Miller, 1990, record it from hosts in 115 genera in 55 plant families (Watson, 2002). Among these host plants are various fruit plants like Juglans regia, Prunus spp. and Ribes spp. (Kuzmin et al,., 2020; Simon et al., 2007; Trencheva et al., 2012).
The main dispersal stage of P. pentagona is the mobile first instar, which can disperse up to 1 m, but are distributed across much greater distances by wind, flying insects and birds (Watson, 2002).
The scale insect can readily be carried on consignments of plant material (e.g. ornamental plants) and fruit, facilitating the spread of this pest from infested consignments into numerous private and public gardens (Watson, 2002; DEFRA, 2016). Crawlers tend to settle in cracks and other irregularities in the bark. They settle on old bark and rarely colonize new growth. Furthermore, it is quite common for crawlers to settle under existing female covers of the previous year (Kuitert, 1967; Hanks & Denni, 1993).
Plants for planting is a possible pathway. However, plants for planting is not considered to be the main pathway in areas where the scale insect is already present (polyphagous and can be carried by e.g. wind).
The Fruit SEWG considered that there are situations with low presence in the environment and where plants for planting should still be considered as a significant pathway compared to others.

Yes

Pseudaulacaspis pentagona is one of the most important armoured scale insect pests in the world, but in general, crop losses caused by P. pentagona are difficult to assess. Trees lose vigour, and their lives are shortened. When P. pentagona becomes newly established in a region this may lead to the loss of whole trees and plantations. Heavy infestations are often found as thick crusts on tree trunks and older branches in temperate regions, and rarely on the roots. The leaves and fruits are not usually infested. The large white colonies of females and males on the branches that make up a heavy infestation are easy to recognize. In the case of heavy infestations, branches or entire trees can die. Heavily infested plants may die some years after the onset of infestation. Younger plants are more susceptible (Plantwise, 2023). Pseudaulacaspis pentagona was described as a very destructive pest, especially on flowering cherry, mulberry, peach and other deciduous fruit trees. It mainly damages deciduous fruits and nuts, including peach, currant, grape, kiwi, walnut (Plantwise, 2023). In the southeastern USA, P. pentagona is a serious pest of Prunus spp. (especially peach) and Pyrus (pear) where infestation can become significant. In the northeastern USA it is a very destructive pest, especially on flowering cherry, mulberry, peach and other deciduous fruit trees (DEFRA, 2016).
In responses to the questionnaire, FR and PL supported deregulation in the EU. FR considered that economic impact was acceptable. PL reported about records in Poland with a 'relatively low intensity'.

Medium

No

Candidate

Candidate

Certification scheme

Candidate