- Author: Mark P Bolda
- Author: Yu-Chen Wang
We had picture brought in by a grower on Friday of some fruit from his field showing clear signs of anthracnose. That is to say, dark, lens shaped lesions on the fruit. It's understood that these are very early fruit and they have been exposed to some pretty tough conditions but nevertheless knowing that this disease is around gives reason for concern for local PCA's and growers.
While temperatures in the upcoming week are leaning on the cool side of the 20-25o C (68-77o F) optimum for the disease, the abundance of precipitation predicted and the resulting splashing onto flowers, fruit and leaves is going to be good for disease growth and spread.
Briefly, anthracnose in strawberry is most often caused by the pathogen Colletotrichum acutatum, and can have a number of sources, including the soil, the surrounding environment or the plants themselves. What we saw are the lesions on the fruit, and these lesions start as small sunken oval to round brown to black spots (some people describe them as “cigarette burns”) that can expand to the entire fruit.
What to do about an anthracnose fruit infestation in strawberry is fairly straightforward. For conventional growers there are several fungicides (see the UC IPM link below for specifics) registered for topical application, and if one is unable or not willing to spray, physical removal of the infested fruit will help to reduce the disease load.
A lot has been written about anthracnose in strawberry already:
https://ipm.ucanr.edu/agriculture/strawberry/anthracnose/
And we at the UC have put out a wonderful grower guideline about it as well:
https://ucanr.edu/blogs/strawberries_caneberries/blogfiles/47929.pdf
And that same guide is also available in Spanish:
https://ucanr.edu/blogs/strawberries_caneberries/blogfiles/47930.pdf
Also, the grower who came spoke Spanish and was wondering if we don't have the UC IPM guidelines in Spanish? Why, of course we do, the link is posted here:
https://ipm.ucanr.edu/legacy_assets/pdf/pmg/pmgstrawberry_espanol.pdf
Even more, Gerald Holmes from the CalPoly Strawberry Center wrote in to remind us of the excellent efficacy and timing guide that can be referenced for anthracnose in strawberry:
https://ipm.ucanr.edu/legacy_assets/pdf/pmg/fungicideefficacytiming.pdf
- Author: Mark P Bolda
Nationally recognized and long time California strawberry entomologist Frank Zalom will join Christine Tabuloc and myself this coming Friday April 19 at my office in Watsonville to discuss recent developments in insecticide resistance in our populations of spotted wing drosophila (SWD). It's no secret to anybody that these flies have been tougher to control as our insecticides lose efficacy because of resistance; this seminar will give some insight as to how and why this is happening with some thoughts at the end by these entomology leaders on what steps to take next.
Meeting set to start at 9:30 am and continue until noon. It's a fairly specialized topic, but all are welcome to attend.
More details can be found in the pdf agenda attached below.
Zalom SWD Resistance Seminar - April 19
- Author: Mark P Bolda
California Berry Cultivars (CBC)will host a field day in Watsonville on Tuesday, May 7th starting at 10:30AM. Content will be solid; along with a presentation and field walk around by CBC staff and a talk on soil disease by Samantha Simard from CalPoly I'll be giving a talk on some findings on cold conditioning in strawberry. A BBQ lunch will be provided afterwards.
Agenda is attached below; key meeting data is here:
When: May 7th, at 10:30AM
Where: 181 Dairy Rd, Watsonville, CA
Look forward seeing you all there!
CBC May 7 2024 Agenda