Cal Poly Strawberry Center Disease Diagnostic Service

Figure 1. A grower field affected by Macrophomina crown rot. About the plant disease diagnostic service Soil-borne pathogens such as Macrophomina phaseolina are challenging strawberry production as they become increasingly prevalent across California (Fig. 1). Accurate disease diagnosis is the cornerstone of integrated pest management. The Strawberry Center's disease diagnostic service has been serving California … Continue reading Cal Poly Strawberry Center Disease Diagnostic Service

Tunnel plastics, UV and powdery mildew

In the vast majority of seasons, powdery mildew (PM) (caused by Podosphaera aphanis) is the most economically important foliar disease of strawberries in California. Many growers have observed that PM is particularly destructive in glasshouses and under plastic tunnels. This could be due to the difference in temperature and relative humidity or to filtering UV … Continue reading Tunnel plastics, UV and powdery mildew

New research shows 1,3-D is effective against Macrophomina

A new publication by Baggio et al. (2022) out of the University of Florida provides evidence that 1,3-dichloropropene (1,3-D) alone and in mixture with chloropicrin were more effective in reducing inoculum of Macrophomina phaseolina than chloropicrin alone. We generally think of 1,3-D (known under the trade name TELONETM) as an effective nematicide with minor efficacy … Continue reading New research shows 1,3-D is effective against Macrophomina

JUST PUBLISHED: Fungicide performance against powdery mildew, 2021

Figure 1. Greenhouse-grown strawberry leaf showing a few powdery mildew lesions. The results of two powdery mildew fungicide trials conducted in 2021 were just published in Plant Disease Management Reports. In these trials, 17 unique products were evaluated for performance against powdery mildew under greenhouse conditions (Fig. 1). Weekly disease incidence and severity was assessed … Continue reading JUST PUBLISHED: Fungicide performance against powdery mildew, 2021

RECENTLY PUBLISHED: Fungicide resistance in strawberry powdery mildew in California

Strawberry powdery mildew caused by Podosphaera aphanis, is an important disease in California strawberries (Fig. 1). Strawberry Center master's student Michael Palmer recently published his work on fungicide resistance in the journal Plant Disease (https://doi.org/10.1094/PDIS-12-20-2604-RE). Because P. aphanis is an "obligate parasite" all of the experiments were done using live plant tissue (Fig. 2). This … Continue reading RECENTLY PUBLISHED: Fungicide resistance in strawberry powdery mildew in California

JUST PUBLISHED: Fungicide performance against Botrytis fruit rot 2021

The results of two fungicide trials conducted in 2021 were just published in Plant Disease Management Reports. In these trials, 20 unique products were evaluated for performance against Botrytis fruit rot (Fig. 1). After 5 applications (Fig. 2), fruit were evaluated in the field (at-harvest) and postharvest after storage at room temperature for 10 days. … Continue reading JUST PUBLISHED: Fungicide performance against Botrytis fruit rot 2021

Frost injury

Recent frosts at the Cal Poly farm has brought frost injury in all its variety. According to the Compendium of Strawberry Diseases "frost injury is probably the most common non-pathogen related and non-insect-related disorder affecting strawberry flowers and fruit." Whenever temperatures dip to below freezing, expect to see a variety of deformed fruit and blackened … Continue reading Frost injury

JUST PUBLISHED: Strawberry host plant resistance to powdery mildew

The author (Michael Palmer) in a strawberry field in Santa Maria, CA. Photo by G. J. Holmes Michael Palmer finished his master's thesis last winter and his second paper just appeared in the journal Plant Health Progress (https://doi.org/10.1094/PHP-12-20-0101-RS). This paper works out the methods for screening strawberry cultivars for their susceptibility to powdery mildew caused … Continue reading JUST PUBLISHED: Strawberry host plant resistance to powdery mildew