Our use of Cookies

This site uses only cookiesstrictly necessaryto ensure the site works correctly.

Please read about how we use cookies.

Hide this message

Strictly necessary and non-essential cookies

Accept all cookies

Accept necessary cookies only

Set Cookie Preferences

By clicking accept all cookies, you agree to our use of cookies and to our cookie policy.

We use third-party cookies on this site.

You have accepted necessary cookies only

You can change your cookie settings at any time

Hide this message

UK Risk Register Details for Phyllachora maydis and Microdochium maydis

Please note: there are high levels of uncertainty associated with the risk scores for this pest.

This record was last updated on 11/05/2022

Common Names

  • Black spot: maize
  • Tar spot: maize

Scenario and Pathways

Scenario for Risk Register

  • show / hide
  • Pest is introduced

Pathway Assessed for Entry to UK

  • show / hide
  • Plant waste

Common Pathways

  • show / hide
  • Fruits or vegetables
  • Plant waste

Risk Ratings and Current Mitigations

Unmitigated Risks

Likelihood [1 - 5] 2
Spread [1 - 5] 3
Impact [1 - 5] 4
Value at Risk [1 - 5] 3
Likelihood x Impact [1 - 25] 8
UK Relative Risk Rating [1 - 125] 24

Current Mitigations

  • show / hide

Key mitigation for pest



Industry Scheme

Contingency Plan



Mitigated Risks

Likelihood [1 - 5] 1
Spread [1 - 5] 3
Impact [1 - 5] 4
Value at Risk [1 - 5] 3
Likelihood x Impact [1 - 25] 4
UK Relative Risk Rating [1 - 125] 12

Proposed Actions

Proposed Actions



Management By Industry

Targeted Survey


Contingency Plan



Distribution and Pest Details


Country / Territory Status Notes
United Kingdom Absent
North America
Mexico Present
United States Present P. maydis only
Canada Present P. maydis only
South America
Bolivia Present
Colombia Present
Ecuador Present
Peru Present
Venezuela Present
Central America
Costa Rica Present
Cuba Present
Dominican Republic Present
El Salvador Present
Guatemala Present
Haiti Present
Honduras Present
Nicaragua Present
Panama Present
Puerto Rico Present
Trinidad and Tobago Present

Type of Pest

  • Fungus

Host or Industry at Risk

  • show / hide

Zea mays

Major Hosts

  • Zea mays L.

Threats to Protected Cultivation

  • N/A

Forest Tree Pests and Pathogens

  • N/A

Further Information

PRA Availability

PRA not available

Regulation and EPPO listing

  • show / hide

Not currently listed

Actions Indicated

  • show / hide


Statutory action on interceptions and outbreaks

General Comments

Fungi found in North America that can cause damage to sweetcorn, particularly if found in combination. Action should be taken on finding either of the two fungi, due to the possibility that the second could arrive and the combination lead to high impacts. A PRA will help to better assess the risk to the UK.

Further Information


  • show / hide

Key uncertainty for pest

There are uncertainties over the distribution of the second, more damaging fungus, which in particular could have consequences for the scores.


Current distribution






UK distribution