This is the fourth and final post in the strawberry anatomy blog series. Root systems are complex, and they can quietly determine how well your crop performs. Understanding how they function can help you make better decisions about irrigation, fertility, fumigation, and runner management. Figure 1. Bareroot strawberry transplant with labeled structures. (photo by G. … Continue reading Strawberry anatomy: part 4 – roots & crowns
Author: Gerald Holmes
Strawberry anatomy: part 3 – leaves and stems
Compared to the flower and the fruit, the anatomy of the strawberry leaf and stems seems like it would be much simpler. But it's not. To begin with, strawberry leaves are trifoliate, meaning that there are three leaflets for each leaf (Fig. 1). Leaves are connected to the crown by a stem called the petiole. … Continue reading Strawberry anatomy: part 3 – leaves and stems
Strawberry anatomy: part 2 – the fruit
We continue this 4-part series on strawberry anatomy by now focusing on the mature fruit. See also, part 1 - the flower. All the structures of the flower are present on the mature fruit, they just look a little different. The calyx is slightly expanded and sits at the "top" or "stem end" of the … Continue reading Strawberry anatomy: part 2 – the fruit
Strawberry anatomy: part 1 – the flower
This is going to be a four-part series on strawberry anatomy. We'll start with the flower (part 1), move to fruit (part 2) and leaves (part 3) and finish on the crown and root (part 4). Knowing a plant's anatomy is important because it helps us understand how it grows and develops and allows us … Continue reading Strawberry anatomy: part 1 – the flower
When mildew evolves: Understanding strawberry powdery mildew’s secret weapon
Powdery mildew is a common disease that affects strawberries and is caused by a fungus called Podosphaera aphanis. It thrives on dry leaf surfaces when weather is mild (between 60° to 80° F) and humidity is high. What does it look like? Early in its development, powdery mildew can be easily overlooked. Infections usually start … Continue reading When mildew evolves: Understanding strawberry powdery mildew’s secret weapon
Current Issues in the Strawberry Industry: 2025 lectures now available
Each year in the Spring academic quarter we invite a series of speakers to Cal Poly to deliver a lecture on a current issue in the California strawberry industry. We just finished this year's series and thought you might like to see the lineup. All lectures are posted to our YouTube channel. Each one is … Continue reading Current Issues in the Strawberry Industry: 2025 lectures now available
The race to cool: keeping strawberries fresh postharvest
Quick cooling and maintaining a fruit pulp temperature of 34°F are essential for reducing spoilage and extending the shelf life of strawberries. With recent temperature increases and more on the near horizon, it's critical to remember: strawberries should be cooled within one hour of harvest. As stated in the 1996 UC publication Handling Strawberries for … Continue reading The race to cool: keeping strawberries fresh postharvest
Strawberry Commission Hosts Regional Strawberry Grower Meeting in Santa Maria, Friday April 25, 2025
CSC-Annual-Production-Research-Meeting-Agenda-04.25.25-1 (1)Download WHEN: Friday, April 25, 2025; 7:30 AM to 2:30 PM WHERE: Santa Maria Fairpark Pavillion; 937 S. Thornburg St., Santa Maria, CA CONTINUING EDUCATION UNITS: 3.5 DPR CEUs hours; 4.5 CCA CEUs hours This is a key strawberry research meeting that brings together the best and brightest in strawberry science. Topics include an … Continue reading Strawberry Commission Hosts Regional Strawberry Grower Meeting in Santa Maria, Friday April 25, 2025
New UC fungicide efficacy table published
Drs. Adaskaveg, Michailides, and Eskalen of the University of California just published the latest edition of "Fungicides, Bactericides, Biocontrols, and Natural Products for Deciduous Tree Fruit and Nut, Citrus, Strawberry, and Vine Crops in California, 2025." Center Director Dr. Holmes and Field Research Manager Kyle Blauer collaborate with these authors on the Strawberry tables found … Continue reading New UC fungicide efficacy table published
What causes fruit splitting?
In early Spring, I often observe a problem on fruit that is very dramatic and consistent. It happens almost every year to some degree and is often more severe in certain cultivars/varieties. The incidence of the problem ranges from less than 1% to as high as 15-20%. Fruit will split down the middle along a … Continue reading What causes fruit splitting?
Why don’t we grow strawberries from seed – REVISITED
Back in August 2023, I wrote a blog post titled "Why don't we grow strawberries from seed." This blog post became way more popular that I expected (over 58,000 views as of 11 March 2025). One potential reason is this week's announcement about Ohala's strawberry consortium to market strawberries as true seed. So, I re-read … Continue reading Why don’t we grow strawberries from seed – REVISITED
Prime time for angular leaf spot
We posted last March about angular leaf spot and it's back this year for a repeat performance. We got about two inches of rain yesterday afternoon and last night. This morning, the angular leaf spot showed so much bacterial ooze that it looked like someone with a bad sinus infection sneezed on the underside of … Continue reading Prime time for angular leaf spot
Fruit size and catfacing
In case you missed it, Mark Bolda and I co-authored a blog on Mark’s Strawberries and Caneberries blog on Feb 17, 2025. The topic is fruit development as it relates to fertilization and development of the achenes and fruit. Catfacing results when fertilization isn't uniform but it may also affect fruit size without causing catfacing. … Continue reading Fruit size and catfacing
BOOK REVIEW: Yielding Fruit – The Life and Times of Royce S. Bringhurst
Royce S. Bringhurst (Fig. 1) helmed the UC Davis strawberry breeding program from 1953 to 1989, leaving an indelible mark on California agriculture. His biography, written by his son John R. Bringhurst, was published in 2018 and is available for purchase here. This 559-page book, supplemented by 165 pages of detailed notes, references, and an … Continue reading BOOK REVIEW: Yielding Fruit – The Life and Times of Royce S. Bringhurst
“Old but Gold”: Meta-analysis shows the value of Captan in strawberries
A team of scientists at the University of Florida, Corteva Agriscience and Syngenta Crop Protection recently published a meta-analysis using data from 25 field trails conducted in Florida from 2005 to 2021. The analysis showed that Captan applications significantly improved marketable yields and reduced Botrytis fruit rot (Fig. 1) and anthracnose fruit rot incidence. They … Continue reading “Old but Gold”: Meta-analysis shows the value of Captan in strawberries
Macrophomina’s host range was exaggerated
Figure 1. Strawberry plants dying from Macrophomina root rot. Because the pathogen attacks the crown and roots, above-ground symptoms are similar to other root pathogens (i.e., wilting, necrosis and death) and accurate diagnosis requires laboratory assays. A paper just published in Phytopathology by Pennerman, Dilla-Ermita and Henry (https://doi.org/10.1094/PHYTO-05-23-0154-R) reports that the host range of Macrophomina … Continue reading Macrophomina’s host range was exaggerated
Current Issues in the Strawberry Industry: 2024 lectures now available
Each year in the Spring academic quarter we invite a series of speakers to Cal Poly to deliver a lecture on a current issue in the California strawberry industry. We just finished this year's series and thought you might like to see the lineup. Most of the lectures are posted to our YouTube channel. Each … Continue reading Current Issues in the Strawberry Industry: 2024 lectures now available
Angular leaf spot showing up
We are seeing quite a bit of angular leaf spot (ALS) in our fields and getting some calls about it in other areas of the state. Angular leaf spot is a bacterial disease caused by Xanthomonas fragariae. It typically shows up this time of year when rains are more frequent. The optimum temperature of the pathogen … Continue reading Angular leaf spot showing up
It’s Botrytis fruit rot season :-(
Our most economically important fruit disease is Botrytis fruit rot (BFR). BFR thrives under cool, wet conditions. Temperatures between 60F and 75F and wetness lasting over 16 hours are ideal for infection and disease development. These conditions are most likely to occur during the winter and early Spring, when fruit supply is low and prices are high. This … Continue reading It’s Botrytis fruit rot season 🙁
New publication confirms trends in fungicide resistance
Figure 1. Botrytis fruit rot often starts beneath the calyx where moisture can get trapped, along with petals, where it will persist long enough for the pathogen to germinate and infect the fruit. (photo by G. J. Holmes) A recently published paper in Phytopathology by Naegele et al. adds to the work done by Cosseboom … Continue reading New publication confirms trends in fungicide resistance
Botrytis and Bees
Wouldn't it be wonderful if we could get bees to deliver an effective agent to strawberry flowers that would protect them from infection by Botrytis cinerea? Researchers in Sweden (Iqbal et al. 2022; https://doi.org/10.1094/PHYTO-05-21-0205-R) used bumblebees to pick up a biocontrol fungus (Aureobasidium pullulans) and deliver it to strawberry flowers, reducing Botrytis fruit rot by … Continue reading Botrytis and Bees
What is the most popular strawberry cultivar grown in California?
It depends on what year(s) you're interested in and if you're talking about public or proprietary cultivars. For example, if you're talking about 2022, 'Monterey' was the most popular public cultivar, grown on 10,003 acres or 33.4% of the total acreage grown in the state. Proprietary cultivars are those held by private companies such as … Continue reading What is the most popular strawberry cultivar grown in California?
Highest rainfall in 18 years
The much-needed rainfall this year has already exceeded annual rainfall for the previous 18 years and we still have two months to go before we're out of our normal wet season. As of January 17, 2023 rainfall for the current Water Year (measured from July 1 to June 30) is at 36.5 inches (927 mm) … Continue reading Highest rainfall in 18 years
New publication reports efficacy of UV-C against powdery mildew in FL and CA
A recent publication by Mello et al. reports that strawberry powdery mildew (SPM) was reduced by nighttime application of UV-C to field plots at 200 J m-2 . Disease reduction was equivalent to that provided by weekly fungicide applications in CA and superior to that provided by twice weekly fungicide applications in FL. No negative … Continue reading New publication reports efficacy of UV-C against powdery mildew in FL and CA
Off-cycle Zythia leaf blotch
We usually see Zythia leaf blotch (caused by Zythia fragariae) during the early spring when plants are small and the weather is cool and wet. With summer planting in Santa Maria occurring in May, especially in fields close to the coastline where fog and heavy dews are common, the same conditions exist (i.e., small plants … Continue reading Off-cycle Zythia leaf blotch