Colletotrichum acutatum Simmonds ex Simmonds 1968 Black spot of strawberry

California Pest Rating for

Colletotrichum acutatum Simmonds ex Simmonds 1968 Black spot of Strawberry
Pest Rating: C


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Posted by tn

2 thoughts on “Colletotrichum acutatum Simmonds ex Simmonds 1968 Black spot of strawberry”

  1. Comments from: Janet C “Jenny” Broome, Ph.D.
    Global Research – Plant Health Dept Manager
    Driscoll’s, Inc.

    I want to share Natalia Peres’ recent paper with you all. And ask why C.a. which is now pretty much C.n. gets a C rating but C.f. which is also in the C.a. species complex and is noted in this paper by Natalia and likely has been here for years as the PCR primers detect it as well as C.n. gets a B rating?

    I saw that the C.a. was open for comment and I wanted to call to your attention that based on the paper, attached, and I was wanting to share, that C. acutatum is generally thought of as a species complex these days, and due to recent molecular characterization of the species complex, it might make more sense to call it C. nymphaeae, or for sure reference this recent work and understanding. And then C. fiorinae is also a member of the C. acutatum species complex, and is reported on strawberry in Florida, and according to Peres’ research likely arrives there on transplants from California, North Carolina or Canada. She reports it as actually less aggressive on strawberry. Unfortunately, I missed the earlier comment period on C.f., but I do think it should also be a C rated pathogen, as likely it has been here for a while on strawberry, as it is a member of the C. acutatum species complex, and the PCR primers often used to detect it would not distinguish between the two. However, for classical mycologists, it does look slightly different in culture, as the paper shows, and has probably been referenced over the years as a “chromogenic isolates” with pink coloration to it, unlike the C. nymphaeae. The spores look identical I believe.

    We just spoke with Natalia Peres two days back and confirmed that likely it has been in California and Florida, and she also agrees that for strawberry, at least, it should be treated the same as, and considered a member of the C. acutatum species complex, and should also be a C rated pathogen in California. And then she sent me this paper by Jim Adaskaveg, UC Riverside, where he mentions the chromogenic isolates in California almonds back in this 1999 paper. And in earlier years we had noticed Colletotrichum isolates from almond when inoculated onto strawberry – I do not know how those colonies looked as Mansun Kong was our lab bench pathologist at that time and has since retired – but he found the “almond isolates” less aggressive on strawberry.
    I can provide more details if that is required in a more formal comment, but first wondered if you all might want to read this paper and let me know when you might be re-opening the rating for C.f.?

    Wang et al., 2019

    Forster and Adaskaveg, 1999
    DOI: 10.1094/PHYTO.1999.89.11.1056

    Thanks, Warm regards, Jenny

    1. Dr. Broome;

      Thank you for the communications and information.

      CDFA has a legal process for pest rating proposals

      While CDFA can review the current pest risk and rating for C. fioriniae in California every 2 years, “Any interested party/organization (in this case, Driscoll’s) may complete the Pest Rating Proposal Form to either propose a change or propose a new pest rating and submit it to CDFA” ( ). This is especially noteworthy when a comment period has expired for a pest.

      California Code of Regulations: 3 CCR § 3162 (c) provide the Pest Rating Process:

      (c) Pest Rating Process.
      (1) Any interested party/organization may complete the California Pest Rating Proposal Form to either propose a change or propose a new pest rating and submit it to the Department. The form and instructions for submitting the form are available at the following Website: 5 (SEE MY NOTE BELOW)
      (2) Within 30 days of completion California Pest Rating Proposal Forms shall be posted for a 45 day public comment period on the Department’s Website at:
      (3) The Department shall respond to any posted comments within 30 working days and shall make the final determination of the pest rating for the organism under consideration.
      (4) All Department pest ratings shall be posted at the following Website:

      NOTE: The website has CDFA’s instructions for submitting the form and contains information in line with what is enumerated in section 3162 (c) above. This form (website also available), is self-explanatory, and can be filled in and submitted directly to the Primary State Plant Pathologist at Providing information for each category in the form is essential for a proper assessment of the proposal. I suggest that Driscoll’s fills and submits the form to clearly state their assessment for posting, review, and response by CDFA in accordance with the above process.

      Please note that assessments must be based on documented reports and official evidence/record of the presence and/or distribution of a pest in California. In other words, references are essential. If non-documented detections are being communicated (especially those that would increase the known in-state distribution of a pest), then they must be verified by official samples collected by a regulatory official (such as the County Ag. Officer) and submitted to the CDFA PPDB Lab for official diagnosis and record.

      Until the entire process for a proposed pest rating/change is complete, the current rating of the pest will remain in effect – with its consequential mitigation actions in accordance with 3CCR §3162 (e).

      I appreciate your expertise as an experienced pathologist as we work through these taxonomic issues.

      Heather Scheck, Primary State Plant Pathologist, CDFA

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