The pest alert system “PestLens” provides information about new reports of plant pests around the world. Notices are published weekly. These provide North American stakeholders advance notice of pests to be on the lookout for. While I have followed these postings for several years, I have been alarmed by recent notices report documenting the presence of insects or pathogens that feed on species in the same genera as tree species native to North American forests. The alerts cover pests of all types of crops, not just trees.
I note that several of these not-yet-introduced pests attack the genus Persea, which contains several native tree and shrub species that are already severely affected by laurel wilt disease.
The report for 19 December, 2024, provided information about two pathogens.
- The bacterium Pectobacterium aroidearum (Gammaproteobacteria: Enterobacteriales) was detected in China. The bacterium infests several crops and Persea americana (avocado). Although the detection in China is new, the bacterium is apparently already widespread, since it has been earlier been reported from parts of Africa, the Middle East, Asia, Brazil, and Jamaica.
- The dagger nematodes Xiphinema simile and X. zagrosense (Longidoridae) were reported in Syria. X. simile is associated with economically important plants, including Cornus spp. (dogwood; North American species already decimated by the introduced pathogen dogwood anthracnose), Malus spp.(apple), Prunus spp. (stone fruit), Quercus spp. (oaks – already under attack by many non-native organisms), and Vitis vinifera (grape). X. zagrosense is also associated with Poaceae. X. simile has earlier been reported from parts of Europe, Kenya, Iran, and Russia. X. zagrosense has also been reported from Iran.
The report for 9 January, 2025, conveyed information about 1 pathogen and 1 insect.
- It noted the presence in Thailand of the fungus Pseudoplagiostoma perseae (Sordariomycetes: Diaporthales) on Persea americana.
- The South American palm borer, Paysandisia archon (Lepidoptera: Castniidae), is infesting several palms at multiple locations in Switzerland. It attacks several economically important palm species and the native genus Washingtonia spp. (fan palm).
The report for 13 February, 2025, gave information about 1 pathogen and 1 insect.
- An anthracnose fungus Colletotrichum aenigma (Sordariomycetes: Glomerellales) infecting Carya illinoinensis (pecan) and Ilex cornuta (Chinese holly) in China. Colletotrichum aenigma infects other economically important plants. These include the following genera with native species in North America: Vaccinium (blueberry), Malus (apple), Persea americana (avocado), and Vitis vinifera (grape). Colletotrichum aenigma is also widespread; it has been reported from parts of Europe, the Middle East, Asia, New Zealand, and South America.
- South African citrus thrips, Scirtothrips aurantii (Thysanoptera: Thripidae) in a greenhouse in the Netherlands. The thrips infests several woody plants, including Ilex crenata (Japanese holly), Rosa spp., Malus (apple), Persea americana (avocado), Prunus spp. (stone fruit), and Vitis vinifera (grape). S. aurantii it is under eradication in Portugal and Spain. It has also been reported from parts of Africa, Yemen, and Australia.
A few weeks ago I wanted to conclude this blog by stating my hope that APHIS is using this information to alert port and on-the-ground staff and perhaps initiating more in-depth risk assessments. Now – as we learn about mindless firings of USDA staff, I fear I must limit my hopes to a future for APHIS’ programs and skilled staff in more general terms.
Do we face shut-down of pest prevention/response efforts across the board?
Posted by Faith Campbell
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For a detailed discussion of the policies and practices that have allowed these pests to enter and spread – and that do not promote effective restoration strategies – review the Fading Forests report here or here.