In a study from 2017 to 2026 conducted under minimal input and nonirrigated conditions, we evaluated 10 modern garden rose ( Rosa × hybrida ) cultivars, three species roses ( Rosa rugosa , Rosa virginiana , and Rosa palustris ), and an heirloom landscape rose, ‘The Fairy’, in Durham, NH, USA. We evaluated landscape performance and symptoms of Cercospora leaf spot and quantified bloom time phenology over a period of several years. The three species roses and ‘The Fairy’ showed over 85% tissue survival after the coldest winter in our study, which reached −13 °F, when the remaining cultivars evaluated showed a moderate amount of winter injury (5% to 32% tissue survival). Size index ranged from 0.11 to 5.07 m 3 , with R. rugosa , R. palustris , and The Fairy significantly larger than many other genotypes. No differences in Cercospora leaf spot ratings were observed in 2024, but in 2026, R. rugosa, R. palustris , R. virginiana , and the cultivars The Fairy and ChewPatout (Oso Easy® Urban Legend) had the lowest Cercospora ratings. The species roses all had a single early bloom period with less than 30% estimated bloom cover, so they lacked flowers for much of the growing season. In contrast, the percentage bloom coverage reached or exceeded 50% during an early-season peak for most modern cultivars evaluated. In addition, the modern cultivars and The Fairy had additional bloom peaks later in the summer, commonly maintaining over 10% bloom and sometimes exceeding 30% bloom throughout the summer and early fall. For those prioritizing cold hardiness, we would recommend the cultivar The Fairy and R. rugosa, R. palustris, and R. virginiana . For those interested in maximizing bloom coverage throughout the season, we would recommend any of the modern cultivars evaluated or The Fairy. Last, for those most interested in late fall bloom coverage, we would suggest the cultivars Meipeporia (Oso Easy® Double Red), RADrazz (Knock Out®), RADtko (Double Knock Out®), or RADcon (Pink Knock Out®).
The United States is a top world blueberry ( Vaccinium spp.) producer. Within the United States, Georgia consistently ranks among the top blueberry-producing states. In 2020, a grower survey was conducted to understand production practices and challenges facing the Georgia blueberry industry. Survey responses represent 4046 bearing acres of Georgia blueberry production (15% of the 2020 statewide planted area). Compared with a 1999 survey, respondents reported increased planting of southern highbush cultivars as well as increased irrigation and yield. Scale insects as well as spotted-wing drosophila, an invasive pest not present during the last survey, were major pest concerns. Damage caused by freeze events continues to be an important issue. A majority of respondents expected to expand their production. At present, the use of plant biostimulants within the Georgia blueberry industry is low. While Extension was growers’ primary source for information about biostimulants, nearly one-third primarily relied on information from commercial sources. Given the continued growth and existing production challenges, research evaluating the effectiveness of soil health practices and biostimulants may be able to offer growers additional tools to mitigate environmental and production related stresses. Additional research examining how information about biostimulants is communicated to and received by growers could help future Extension and industry outreach efforts.
We developed and validated a diagrammatic scale (DS) for assessing freeze-induced leaf damage in Citrus spp. The proposed DS consists of six color images representing severity levels ranging from 6.9% to 84.1% of affected leaf area. Validation was performed using 15 raters, who assessed the same set of 20 leaf images independently in two consecutive evaluations: first, without the DS and, second, using it as a visual aid. Accuracy, measured by the bias accuracy correction factor, increased from 0.84 to 0.91 with the use of the DS; precision, measured using the correlation coefficient, increased from 0.86 to 0.89. Overall agreement, assessed using Lin’s concordance correlation coefficient, improved from 0.73 to 0.81. In addition, the reliability of the estimates increased with the DS, as indicated by a greater coefficient of determination (r2 = 0.74 vs. 0.80), and scale and location shift values closer to the ideal values of 1 and 0, respectively. These results demonstrate that the DS improved significantly the accuracy, precision, and reliability of visual assessments of freeze-induced leaf damage in Citrus spp.
Bell pepper (Capsicum annuum L.) is a high-value vegetable crop, and its productivity in greenhouse and controlled-environment systems depends strongly on irrigation and nutrient management. Arbuscular mycorrhizal fungi (AMF) have been proposed as biological tools to improve plant water and nutrient acquisition, but their functional value in intensively managed vegetable systems remains uncertain. This study evaluated whether commercial AMF inoculation improves physiological performance, growth, yield, nutrient status, and root colonization in greenhouse-grown bell pepper. Two complementary experiments were conducted using a commercial AMF product containing Rhizophagus irregularis, Funneliformis mosseae, Rhizophagus aggregatum, and Claroideoglomus etunicatum. In the first experiment, pot-grown plants were subjected to well-watered or water-deficient irrigation regimes, with or without AMF inoculation at seeding. Water deficiency reduced stomatal conductance, increased leaf temperature, decreased plant height and biomass, and substantially reduced fruit yield relative to well-watered conditions. Although AMF-inoculated plants showed measurable root colonization, inoculation did not improve water consumption, delay wilting, increase stomatal conductance, enhance photochemical efficiency, or mitigate yield losses under water deficit. In the second experiment, the timing and method of AMF application were evaluated at two nitrogen fertilizer rates. Inoculation at seeding and direct placement near the root zone increased AMF colonization compared with later or irrigation-based application methods; however, neither inoculation treatment nor nitrogen rate significantly affected plant height, shoot or root biomass, fruit yield, foliar nutrient status, or time to flowering. Overall, these results indicate that AMF root colonization does not necessarily confer physiological or agronomic benefits in intensively managed greenhouse bell pepper production. The effectiveness of commercial AMF bioinoculants appears to be highly context dependent and may be limited when irrigation and fertigation already provide favorable resource availability.
Uncovering and closing operations of thermal insulation rolling curtains in solar greenhouses in cold and arid regions lacks quantitative standards, and traditional management experience is difficult to adapt to the light-temperature characteristics of double-layer shed structures. Using a solar greenhouse with an inner arch shed for overwintering celery cultivation as the experimental object, we conducted continuous in situ monitoring of CO2 concentration, air temperature, and light intensity inside the greenhouse in winter. Three classic photosynthetic models—the nonrectangular hyperbola, exponential equation, and modified rectangular hyperbola models—were selected to construct a multifactor integrated photosynthetic model by coupling temperature and CO2 concentration correction factors. The dynamic changes of crop net photosynthetic rate under different curtain uncovering times were quantitatively simulated to screen the optimal uncovering period of the thermal insulation rolling curtain. The results show that after curtain uncovering in the morning, light radiation intensity is the dominant regulatory factor of net photosynthetic rate, with a significantly higher influence weight than temperature and CO2 concentration. Under sunny conditions, 8:30 to 9:00 AM is the rapid growth window of net photosynthetic rate, which is the optimal operation interval for uncovering the thermal insulation rolling curtain. Under cloudy conditions, the photosynthetic rate increases gently, and uncovering the curtain at ∼9:30 AM can balance thermal insulation safety and photosynthetic production efficiency. The research results can provide a theoretical basis and technical reference for the refined environmental regulation of solar greenhouses with inner arch sheds in cold and arid regions of northern China in winter.
