Day-neutral strawberry cultivars Albion and San Andreas were cultivated hydroponically in a climate-controlled greenhouse (temperature and light regulated) to assess fruit quality and anthocyanin composition, which are important attributes for flavor and color (visual appeal), respectively. Fruits were collected from 6 Feb 2023, until 18 May 2023, at Auburn University, AL. Soluble solids content (SSC), titratable acidity (Tacid), pH, total phenolics (TPC), and anthocyanins [total anthocyanins (TAC), cyanidin-3-glucoside (C3G), pelar-gonidin-3-glucoside (P3G), pelargonidin-3-rutinoside (P3R), pelargonidin-3-malonylglucoside (P3M)] were determined from the juice of thawed frozen fruits. Average fruit yield (Fyield; g & centerdot;plant-1) was similar between cultivars. Both cultivars were similar for SSC, Tacid, TPC, TAC, and the major pigment (P3G) when averaged across days after transplanting (DAT). Pelargonidin-based pigments predominantly characterized the anthocyanin profile. Minor pigments differed, with more C3G (mg 100 g/fresh weight) in 'Albion' than in 'San Andreas' (0.39 and 0.18, respectively), whilst 'San Andreas' had more P3R (mg 100 g/fresh weight) than 'Albion' (2.26 and 1.81, respectively). Plant age (DAT, non-replicated) influenced SSC, Tacid, and most of the anthocyanins. Fyield, Tacid,and SSC were higher in plants at 140 DAT (early spring), but lower in plants at 180 DAT (late spring), indicating a potential plant age effect on fruit productivity and quality. Correlation analysis indicated a robust positive correlation between TAC, C3G, pelargonidin anthocyanins (P3G, P3R, P3M), and Fyield, whereas Fyield was inversely correlated with Tacid and TPC. Our results indicate that strawberry fruit quality is influenced by cultivar-specific pigment profiles, seasonal variations, and yield interactions, highlighting the need to balance productivity with market-preferred traits in hydroponic greenhouse systems.

The prediction of floral bud progression in commercial peach cultivars promotes knowledge about the adaptability of cultivars to the climatic conditions in a specific location under a climatic variability context. Phenology is relevant to improving the scheduling of cultural practices in peach orchards. This research aimed to predict the floral bud progression of three peach cultivars: ‘Harvester’, ‘Red Globe’, and ‘Rubyprince’. Floral bud progression was assessed using one-year-old shoots collected from an orchard located at the Chilton Research and Extension Center, Alabama. Samples were evaluated under laboratory and growth chamber conditions. We recorded the flower developmental stages daily to identify the transition among stages. Daily temperature records were used to estimate the heat requirement in terms of Growing Degree Days (GDD). After dormancy release, samples needed between 23 to 39 and 37 to 42 days to reach the petal fall stage for season 1 and season 2, respectively. In terms of heat requirements, cultivars needed between 425.5 to 721.5 and 684.5 to 777 GDD to end flowering. A logistic curve was adjusted to describe the growth of the different floral stages over time. The results are key to supporting peach growers in crop management practices such as orchard establishment, irrigation, fertilization, freeze and frost protection, and pollination under climate variability scenarios.

Sterol demethylation inhibitor (DMI) fungicides continue to be essential components for the control of brown rot of peach caused by Monilinia fructicola in the United States and worldwide. In the southeastern United States, resistance to DMIs had been associated with overexpression of the cytochrome P450 14α-demethylase gene MfCYP51 as well as the genetic element Mona, a 65 bp in length nucleotide sequence located upstream of MfCYP51 in resistant isolates. About 20 years after the first survey, we reevaluated sensitivity of M. fructicola from South Carolina and Georgia to propiconazole and also evaluated isolates from Alabama for the first time. A total of 238 M. fructicola isolates were collected from various commercial and two experimental orchards, and sensitivity to propiconazole was determined based on a discriminatory dose of 0.3 μg/ml. Results indicated 16.2, 89.2, and 72.4% of isolates from Alabama, Georgia, and South Carolina, respectively, were resistant to propiconazole. The detection of resistance in Alabama is the first report for the state. All resistant isolates contained Mona, but it was absent from most sensitive isolates. It was unclear if the resistance frequency had increased in South Carolina and Georgia. However, the resistance levels (as assessed by the isolate frequency in discriminatory dose-based relative growth categories) did not change notably, and no evidence of other resistance genotypes was found. Analysis of the upstream MfCYP51 gene region in the resistant isolate CF010 revealed an insertion sequence described for the first time in this report. Our study suggests that current fungicide spray programs have been effective against increasing resistance levels in populations of M. fructicola and suppressing development of new resistant genotypes of the pathogen.

Peach is an important specialty fruit crop in the United States, and phony peach disease (PPD), caused by Xylella fastidiosa subsp. multiplex, has been a major cause of yield loss since it was first observed in 1885. Under a federal eradication program, surveys of PPD were conducted from 1929 to 1972, when the program was terminated. No surveys have been conducted in approximately 50 years; therefore, the current prevalence of PPD in the United States is unknown, especially in the Southeast, where damage was previously most severe. To ascertain the status of PPD, we surveyed orchards in Alabama, Florida, Georgia, and South Carolina from June to August 2020 and, except for South Carolina and northern Georgia, PPD was prevalent. Trees in 17 orchards were subjected to confirmation of X. fastidiosa using the AmplifyRP XRT+ for X. fastidiosa to corroborate our visual assessments; based on these tests, PPD incidence in the orchards ranged from 0 to 30.5%. Ancillary written surveys of relative PPD presence and prevalence were sent to fruit pathologists from universities in 20 states where PPD was historically reported. Only 35.0% of respondents reported that PPD either currently or recently occurred in their state and, of these, three reported PPD to be of significant concern. The results of the physical and written surveys indicate that PPD remains prevalent mainly in the southeastern region of the United States but, in other states where previously reported, it is either not present or has very low prevalence when compared with historical accounts of the disease.

Stink bugs, including Halyomorpha halys (Stål) and Nezara viridula (L.), are agricultural pests that feed on fruit in a variety of crops. Monitoring predation and parasitism of stink bug egg masses furthers our understanding of potential biological control tactics. However, best practices for laboratory and field assessments of parasitism and predation of egg masses require further attention. We carried out a series of laboratory and field experiments to test whether parasitism and predation for three types of sentinel H. halys egg masses, fresh, frozen, and refrigerated, varied in agricultural commodities. In addition, we asked if predation and parasitism differed between sentinel and naturally occurring H. halys and N. viridula egg masses in soybean. In the laboratory, more H. halys eggs were parasitized by Trissolcus euschisti (Ashmead) (Hymenoptera: Scelionidae) if they were frozen or refrigerated compared to fresh eggs. Similarly, in the field, parasitism was higher for frozen egg masses than fresh. In 2018 and 2019, H. halys natural egg masses had higher parasitism and lower predation compared to sentinel egg masses in soybean. In a paired field test during 2020 and 2021, there was no difference in parasitism between H. halys natural and sentinel eggs, but much higher incidence of parasitism was detected in natural N. viridula egg masses than sentinel eggs. Collecting natural egg masses is the best methodology for field assessment of parasitism of stink bug egg masses; however, if natural egg masses are not easily available, deploying refrigerated sentinel egg masses is a good alternative.

Phenological shifts in peaches have been observed over the last few years due to the fluctuation of the seasonal climate conditions experienced during dormancy, affecting orchard management practices and influencing production and harvest dates. This study aimed to model the vegetative and floral budbreak of selected peach cultivars. Three peach cultivars, including “Rubyprince”, “Harvester”, and “Red Globe”, were considered in this study based on the representation of the early, early-mid, and mid-seasons. The prediction of the budbreak in peaches was assessed using different models that integrate the combination of chill and heat requirements. Models used include the Weinberger model, the modified Weinberger model, Utah, the dynamic model, and the growing degree model. The accumulation of chill varies according to the season evaluated. A model that considers both chill and heat accumulation is presented for each cultivar. Budbreak as an indicator of dormancy completion was established for each cultivar. The outcome of this study is to determine the amount of chilling accumulation and thermal time required to mark the beginning of the budbreak in selected cultivars with a model that predicts the duration of the dormancy. These results are valuable information that can be used for crop management practices and support the mitigation of cold damage during this critical period of crop development.

Methyl benzimidazole carbamate (MBC) fungicides were once widely used for brown rot (Monilinia fructicola) control of peach (Prunus persica (L.) Batsch) in the southeastern US, but their use was substantially reduced and often eliminated due to widespread resistance. In this study, 233 M. fructicola isolates were collected from major peach production areas in Alabama, Georgia, and South Carolina, and sensitivity to thiophanate-methyl was examined. Isolates were also collected from one organic and two experimental peach orchards. A discriminatory dose of 1 μg/ml was used to distinguish sensitive (S) and moderately sensitive (S-LR) isolates from low resistant phenotypes, while 50 and 500 μg/ml thiophanate-methyl concentrations were used to determine high resistant (HR) phenotypes. Sequence analyses were performed to identify mutations in the β-tubulin target gene and detached fruit assays were performed to determine the efficacy of a commercial product against isolates representing each phenotype. Results indicated 55.7%, 63.5%, and 75.9% of isolates from Alabama, Georgia, and South Carolina, respectively, were S to thiophanate-methyl; 44.3%, 36.5%, and 21.4% were S-LR; no isolates were LR; and only 3 isolates (1.3%) from South Carolina were HR. No mutations in S or S-LR isolates were found, but HR isolates revealed the E198A mutation, an amino acid change of glutamic acid to alanine conferring high resistance. The high label rate of a commercial product containing thiophanate-methyl controlled brown rot caused by S and S-LR isolates in detached fruit studies but was ineffective against HR isolates. The combinations of thiophanate-methyl with azoxystrobin or isofetamid, when mixed together and applied in an experimental orchard 14 days preharvest, significantly reduced brown rot incidence on pre and postharvest commercially ripe fruit and efficacy was comparable to that of a grower standard fungicide. These results indicate that thiophanate-methyl may again be useful to peach growers in the southeastern US for brown rot and fungicide resistance management.

The invasive brown marmorated stink bug, Halyomorpha halys (St($)over-circlel) (Hemiptera: Pentatomidae), is an agricultural and nuisance pest in Georgia and Alabama, USA. Natural enemies may provide significant suppression of the brown marmorated stink bug, and sentinel egg masses are deployed commonly on plants in the field to measure their effects. The objective of this study was to evaluate the effect of deployment duration (2-5 d) on parasitism and predation of brown marmorated stink bug sentinel egg masses in plum, peach, blueberry, tomato, sassafras, corn, and soybean in these 2 states. Retrieved egg masses were processed to quantify rates of predation and parasitism and identify parasitoid species and predation types. Across crops, predation and parasitism were higher significantly in plum at 5 d compared to 2 d deployment but was similar in soybean regardless of exposure time in 2017. Predation and parasitism were higher significantly after 5 d of exposure compared to 2 d and 3 d whereas parasitism was significantly higher at 3 d compared to 2 d exposure in 2018 to 2020. For individual crop trials, though, effects of time of exposure were tested in different yr, sampling dates, and crops with variable results. When significant differences were detected for parasitism in plum, peach, tomato, and sassafras, a 5 d deployment resulted in higher parasitism compared to 2 d. Given the variability of factors that affect parasitism and predation under field conditions, we conclude that a 5 d deployment is optimal and a 3 d exposure time is minimal for assessing predation and parasitism. An additional benefit for a 5 d exposure is that it increases the probability of detecting hyperparasitism.

Consumer awareness of the health promoting qualities of strawberries has sparked a nation-wide expansion in demand. The Alabama strawberry industry is a part of the South Atlantic Region (SAR), which is the third most productive region in the United States. While strawberry cultivar selection is crucial to the growth of this industry, the most productive cultivars used in SAR are from California breeding programs. Furthermore, there is little documented information concerning the performance and the antioxidant qualities of these strawberry cultivars in Alabama. The objective of this study was to determine the production potential and antioxidant concentration of selected strawberry cultivars produced in Alabama to enhance the sustainability of the strawberry industry in the state and the SAR. A strawberry cultivar evaluation was conducted in Central Alabama over a five-year period. Included in this trial were 'Albion', 'Camino Real', and 'Ruby June', the current market standard 'Camarosa' and the former market standard 'Chandler'. Plant size was smallest for 'Camino Real', offering an opportunity for producers to increase the number of plants per hectare. In contrast, 'Ruby June' produced fewer stolons per plant, thus reducing labor costs. Of the most recently developed cultivars 'Camino Real', 'Ruby June', and 'Albion', 'Camino Real' and 'Ruby June' were the most comparable to 'Camarosa' in both early and total yield. Both cultivars produced a significantly lower number of cull fruits per hectare. 'Albion' produced the largest individual fruit weight during the first season, but all cultivars were similar to the market standard 'Camarosa' in fruit weight in subsequent seasons. Soluble solids concentration (SSC) varied with season and cultivar. 'Ruby June' SSC was significantly higher than all other cultivars in 2018, and similar to 'Camarosa' in 2017. In contrast, 'Albion' and 'Camino Real' had the lowest SSC in 2018 and were similar to 'Camarosa' in 2019. Titratable acidity (Tacid) and SSC:Tacid ratio of 'Camino Real' tended to be numerically lower than other cultivars though differences were not statistically significant at the 5% level. Total monomeric anthocyanin and phenolic concentrations were consistently among the lowest for 'Ruby June' although SSC, pH, and titratable acidity indicate fruit were fully ripe. Plant and fruit qualities and yield potential indicate that 'Camino Real' can serve as a desirable cultivar to replace 'Camarosa' in the SAR.

The Actinidia chinensiscultivars, ‘AU Golden Sunshine’ and ‘AU Gulf Coast Gold’ produce heavy crop loads of large, commercially acceptable kiwifruit in central Alabama. However, due to fluctuations in annual winter temperatures, these vines may not always receive sufficient amounts of chilling hours or units or portions they require to break bud and flower effectively. When these vines do not receive 700–900 chilling hours, they can exhibit nominal and intermittent bud break and flowering. This leads to insufficient cropping and negative economic impacts for growers. Experiments were conducted over 2 years on ‘AU Golden Sunshine’ and ‘AU Gulf Coast Gold’ to determine the effectiveness of the dormancy breaking chemical, hydrogen cyanamide (HC). Applications of HC were made ~28 (1 Feb.) and ~14 (15 Feb.) days before natural bud break to assess the effect on timing of application. Bud break was advanced in response to HC applications, with earlier applications causing bud break to occur earlier. In year one, vines receiving applications ~14 days before natural bud break showed increased bud break and flowering intensity as well as a reduction of lateral flower buds over the vines treated at ~28-day before natural bud break. The nontreated controls had the fewest lateral buds throughout the study. During year two, all vines were injured by a late frost event that occurred 7 Mar. 2019. Vines receiving the earliest HC applications were damaged the most, followed by the vines receiving the second HC application, which led to reduced flower production compared to nontreated vines. Control vines had the greatest number of floral shoots after the frost event because they were the last to experience bud break. Hydrogen cyanamide may be a beneficial tool to growers experiencing lower than normal chilling, however caution is advised due to the possibility of late spring frost.