Page 32 - Simply Vegetables Spring 2022

Planting seed potatoes protects your and our biosecurity.
Finally, there are hitchhikers that
arrive on food. Some of you might know of the Colorado beetle (Leptinotarsa decemlineata). You’ll have noticed a Solanaceae pattern by now – the beetle’s larvae are voracious foliage feeders of the potato and other plants in the nightshade family. The Americans have found that
it is resistant to most chemicals, and it
is widespread in most countries of the northern hemisphere, but not in the
UK. We want to keep it that way. We occasionally find the beetle on imported lettuce, carrots and other crops from fields that had recently grown infected potatoes, or photographs on social media posts containing images of Colorado beetle with the strapline “What is this beastie?”. At which point Plant Health leaps into action, and we send out an inspector to investigate.
Inspectors are not immune from pests and diseases in their own allotments. In the summer of 2020, my sweetcorn was attacked by what look remarkably like
a quarantine corn borer I’d found when inspecting baby corn from Asia (Ostrinia furnacalis). Mine turned out to be the European corn borer (Ostrinia nubialis)
and was one of two strains in the UK.
This was the Z strain, which has been attacking maize in the UK since 2010. The E strain, known to have been here since the Thirties, has previously been found only on Artemisia.
Plant Health inspectors also regularly test for emerging pests and diseases.
My most recent survey was for blueberry rust (Thekopsora minima). It was initially recorded in both Japan and North America and has since been recorded elsewhere. Blueberry production in Australia and the US has been badly affected by it. Its small yellow spots develop, enlarge, coalesce and become necrotic. They can develop
on the fruits and cause premature leaf drop and defoliation. You can read all about it and find pictures on the Plant Health Portal.
The survey was part of our regular work for the Defra Risk & Horizon scanning team. They conduct pest risk analyses
of pests and diseases coming our way
and could be a threat to our economy, environment, and biosecurity. It is essential that we prove the negative as well as the positive.
If the UK wants to add regulations to control the import of a pest or disease on a plant or produce, according to International Plant Protection Convention (IPPC) rules,
a country has to prove that the pest is
not known to occur in that country. We regularly take samples of Xylella high-risk hosts (olives, lavender, rosemary, coffee plants, Polygala myrtifolia and almond trees) to prove that we are free from the bacterium. Samples are sent to the lab throughout the year but mainly in the active growing season in high summer. I also do vineyard inspections, taking leaf samples from the 30-something vineyards in the county to test for Xylella and leafroll virus.
Next year we are expanding the pathogens we test for. The work of Plant Health is never done.
Get involved with National Plant Health Week (9th to 15th of May) and show off your beautiful healthy plants - Plant Health 2022 (planthealthaction.org)
HELPFUL WEBSITES
Plant Health Portal https:// planthealthportal.defra.gov.uk/
Forestry Research (www.forestresearch. gov.uk)
Observatree (www.observatree.org.uk) Monitoring tree health
Tree Alert (www.forestresearch.gov.uk/ tools-and-resources/fthr/tree-alert) Alerting Forest Research about potentially harmful tree pathogens
BeeBase www.nationalbeeunit.com
Plant and seed imports guidance: google Guidance: import requirements for plants, plant produce and products
https://www.gov.uk/government/ publications/plant-species-by-import- category/import-requirements-for-plants- plant-produce-and-products
European and Mediterranean Plant Protection Organisation (EPPO) www.eppo.int
Centre for Agriculture and Bioscience International (CABI) www.cabi.org
Garden Organic www.gardenorganic.org. uk/pests-and-diseases
RHS new pest and disease risks www.rhs. org.uk/science/plant-health-in-gardens/ protect-your-garden/new-pd-risks
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