Virginia Cooperative Extension

California produces approximately 80% of the world’s almonds [Prunus dulcis (Miller) D. A. Webb]. In May of 2024, yellow spots and orange to dark red-brown blotches, were detected in an almond orchard (Nonpareil, Monterey, and Fritz cvs.) in Merced County. Similar symptoms were observed during June of 2024 from 12 additional orchards in Fresno, Madera, Merced, San Joaquin, and Stanislaus counties. Disease incidence in orchards varied from a few infected leaves to nearly 100%. Symptoms were characteristic of red leaf blotch caused by the fungal pathogen Polystigma amygdalinum. Leaves from all orchards were collected and taken to the laboratory in sealed resealable bags to conduct morphological and DNA analyses to identify the pathogen involved. For molecular identification, we used a quantitative real-time PCR detection method, and a primer pair (PamyI2F4/PamyI2R2) previously developed for P. amygdalinum (Zúñiga et al. 2018). Following direct DNA extraction from necrotic leaf tissues, the assay confirmed the detection of P. amygdalinum in symptomatic leaves. In addition, four lesions on separate leaves from different orchards were selected for genomic DNA extraction and sequencing of the internal transcribed spacer region (ITS) using ITS1F/ITS4 primers (Gardes and Bruns 1993) and a segment of the 28S region of the large subunit (LSU) ribosomal RNA gene using LR5 and LR0R primers (Guterres et al. 2018). Resulting sequences (ITS: GenBank Accession PV491257-PV491260; LSU: GenBank Accession PV487836-PV487836) were compared to reference sequences (Habibi et al. 2015; Guterres et al. 2018) using BLAST analysis. The ITS sequences of the Californian isolates were 100% identical to at least one of P. amygdalinum reference strains MH205935 or KC756362; LSU sequences were at least 99.46% similar to that of P. amygdalinum reference strain (KM111540.1). Morphological analyses were done by mounting sections of necrotic leaves on microscopic slides for observation under a light microscope (Leica DM2000 LED Microscope, Wetzlar, Germany). Conidiomata consisted of globose pycnidia, 80-120 μm diam. Conidia were hyaline, aseptate, filiform, 22.1 to 36.9 × 1.6 to 2.5 μm (n = 60). Perithecia formed in fallen leaves during January and were flask-shaped and contained clavate asci with eight ascospores. Asci were 95.4 to 129.5 × 18.3 to 25.1 μm. Ascospores were aseptate, ovoid to cylindrical with one end round and one end slightly acute, sometimes slightly constricted in the middle, hyaline, and measured 15.2 to 20.7 × 6.1 to 8.4 μm. Pathogenicity tests were conducted on potted, 1-year-old almond trees (cv. Monterey and Nonpareil) under greenhouse conditions. An ascospore suspension of 1 × 104 ascospores·ml-1 was obtained by crushing fallen almond leaves that contained mature perithecia of P. amygdalinum. The emerging leaflets from 10 plants of each cultivar were spray-inoculated with the ascospore suspension and then covered with plastic bags for 48hrs. After 40 days, typical symptoms of red leaf blotch appeared on leaves of all inoculated plants for each cultivar and no symptoms occurred in the control plants. Koch’s postulates were satisfied after confirming P. amygdalinum from symptomatic leaves through molecular identification as described above. This is the first detection of P. amygdalinum from almond in California, the United States, and North America. These findings improve our knowledge of the etiology and biology of red leaf blotch of almond in California.

Abstract Biomass sorghum [ Sorghum bicolor (L.) Moench] is an alternative biofuel feedstock to maize [ Zea mays (L.)]. One advantage of biomass sorghum over maize is relatively lower nitrogen (N) requirement and its ability to tolerate late planting or fit into double cropping systems. To evaluate the most economic rate of N (MERN) for biomass sorghum in the Mid‐Atlantic region, a 3‐year (2017, 2018, and 2019) field trial was conducted at two locations (Holland and Hare) in Southeastern Virginia. Treatments were two planting dates (early [EP] versus late [LP]) and seven N rates (0, 56, 112, 168, 224, 280, and 336 kg ha −1 ) conducted in six environments. Data on dry matter yield of biomass sorghum, plant height, stem diameter, susceptibility to foliar diseases, and stalk lodging were recorded. Between the two planting dates, EP had 52%, 19%, and 16% higher dry matter, plant height, and stem diameter, respectively, compared to LP. However, LP exhibited lower disease pressure in four of 6 site‐years and lodging severity likely in response to weather conditions. Nitrogen rates between 112 and 224 kg ha −1 significantly improved dry matter, plant height, and stem diameter, with lower disease and lodging severity. At the MERN of 123 kg ha −1 , dry matter yield (20.66 Mg ha −1 ), plant height (454 cm), disease (61%), and lodging severity (34%) were least as compared to other treatments. Application of N at 123 kg ha −1 can provide the highest economic return while reducing the potential for N loss in the Mid‐Atlantic region.

Abstract Agricultural conservation practices are often used to protect stream health while continuing food production. However, recovery of stream health is often not as rapid or extensive as planned. The efficacy of practices may be improved by promoting their continued use by landowners (i.e., persistence) after cost‐share contracts with government agencies end. Persistence rates and their drivers are typically unknown. Therefore, we mail‐surveyed 889 landowners to understand persistence in grazing practices in southwest Virginia. Survey responses were analyzed quantitatively using logistic regression and qualitatively via coding. We found that persistence rates for vegetative practices, cattle‐exclusion fencing, off‐stream watering structures, and pasture management were 74%, 84%, 94%, and 94%, respectively. Both the quantitative and qualitative analyses indicated that landowner cognitions (i.e., attitudes toward practices, environment, and agencies), environmental motivations, and practice durability influence persistence. Our results highlight that persistence could be encouraged by: (1) providing targeted messaging that demonstrates persistence benefits and aligns with landowners' motivations, (2) ensuring that responsibility to maintain practices is transferred during land‐tenure changes, and (3) allocating more agency funding to practice maintenance.

Groundwater nitrate contamination is largely attributed to fertilizer and intensive livestock manure inputs in agricultural systems. California's Salinas Valley is an area where regional policy is aimed at reducing nitrate leaching. Nonlegume winter cover crops can help decrease nitrate leaching by scavenging residual soil nitrogen (N) during winter fallow periods following the cropping season. However, the ability of fall-incorporated cover crops to decrease nitrate leaching and recycle N to subsequent cash crops is unknown. We conducted a 112-day laboratory soil incubation experiment using Merced rye (Secale cereale) cover crop shoot biomass, with four carbon-to-nitrogen (C/N) ratios (10, 14, 19, and 30), at three temperatures (10°C, 15°C, and 20°C). Destructive soil sampling was done at six intervals during the incubation to measure plant-available nitrogen. Rye biomass with the lowest C/N ratio (10) had the highest average nitrogen mineralization (Nmin) rate (56%) at the warmest temperature (20°C). Conversely, biomass with the highest C/N (30) showed net nitrogen immobilization at 10°C and 15°C during the incubation, transitioning to net mineralization only at 20°C. We found a linear correlation between soil temperature and nitrogen mineralization (at Day 112) for higher C/N ratios. Furthermore, doubling the soil mineral nitrogen content had a negligible impact on the percent mineralization of the C/N 30 residue. These results provide useful information to help farmers and policymakers understand mineralization dynamics from fall-, winter-, or spring-terminated cereal cover crops.

Exercise protects against several diseases including cardiometabolic disorders. However, the molecular mechanisms driving these adaptations remain incompletely defined. Endothelial nitric oxide synthase (eNOS), a key source of nitric oxide (NO), is implicated in regulating glucose uptake, fatty acid metabolism, and mitochondrial remodeling in response to exercise. eNOS is expressed in both endothelial and non-endothelial cells and its effects on metabolism are multifaceted. Notably, eNOS is highly expressed in endothelial cells which are ubiquitous throughout all organ systems allowing them to closely integrate with surrounding cell types. This unique feature of the endothelium enables eNOS to influence both local microenvironments and signaling across organ systems. This review summarizes current findings on the role of eNOS-derived NO in exercise metabolism. Evidence suggests eNOS contributes to improved metabolic flexibility, enhanced mitochondrial function, and tissue crosstalk. However, data across experimental models remain mixed, with both supportive and conflicting results. Collectively, the literature indicates that eNOS plays a central, though context-dependent, role in facilitating exercise-induced metabolic benefits. Identifying the specific mechanisms and tissue contributions of eNOS activity remains an important area for future investigation, with potential relevance to metabolic disease prevention and treatment.

Boxwood blight, caused by the fungal pathogen Calonectria pseudovaniculata, has been reported in over 30 U.S. states and is a threat to boxwood production worldwide. While considerable research has been conducted to evaluate the efficacy of conventional fungicides and cultural controls for this disease, the potential of host defense inducers remains largely unexplored. This study evaluated the effects of application method and frequency for managing boxwood blight in both container and field production systems in 2018 and 2019 at two locations in North Carolina. Actigard 50WG (acibenzolar-S-methyl) and LifeGard WG (Bacillus mycoides isolate J) were applied as drench and foliar treatments to container-grown boxwoods artificially inoculated with C. pseudonaviculata and to field-grown boxwoods exposed to natural inoculum. Drench applications of Actigard resulted in lower disease incidence than the untreated control plants under container production. High efficacy of Actigard was also observed under field production despite favorable environmental conditions for the development of boxwood blight. Application frequency did not affect disease for either of the tested host defense inducers in either production system. These findings support the integration of host defense inducers into cultural practice- and conventional fungicide-based management programs for boxwood blight.