The trial run in Watsonville, California, showed a numerical reduction of eggs when the food grade gum was applied as standalone and in combination with pesticide. As discussed previously, multiple factors may have impacted the trial. Meta-analysis to determine differences between food-grade gum and untreated control and mean larvae resulted in a highly significant difference. Despite the non-statistical significant results gotten in multiple trials, the meta-analysis showed that by analyzing together all the trials, the food-grade gum has a significant positive effect on protecting fruits from D. suzukii infestation. The data originated clearly indicate that the presence of the food-grade gum substrate is a valid approach to keep D. suzukii away from berries. This analysis seems extremely valuable because it provides a general idea of how, overall, the use of the new tool has the potential to bring benefits to the small berry industries all over the world. The parameters used for modeling simulations were obtained from previous laboratory and semi-field experiments. For this study, the initial D. suzukii adult densities were fitted to match the untreated control treatment. The relatively similar trends displayed between simulations and real data suggest that model assumptions are close to representative of treatments.

The simulations suggest an earlier buildup of D. suzukii populations compared to the sudden increase of infestation in the field trial. A reason for this difference could be that the model output was compared with the experimental data by assuming that the simulated egg population is proportional to the mean number of eggs found per fruit in the experiments. This assumption is reasonable for constant fruit levels, stackable planters but the availability of ripe fruit in the trials were not constant. Under commercial field conditions, fruit is harvested every 7-10 days for this cultivar. This means that less susceptible fruit is available directly after every harvest event, likely negatively impacting D. suzukii population levels. Therefore, a high availability of ripe fruit in the middle portion of the experiment likely resulted in fewer eggs laid per berry compared to later in the season when fruit are less available. These differences in ovipositional resources likely resulted in the sudden increase in recorded infestation levels towards the latter portion of the experiment. Future work should focus on these relationships of pest population level and crop availability to determine risk. Finally, data collected under different environmental conditions over periods ranging from 10 to 60 days do not appear to impact the efficacy of the food-grade gum. Treated fruits were less damaged by D. suzukii. Additional factors such as active distance, commercial field longevity and improved formulation will result in additional improvements and future adoption.

Elderberry is a part of the Viburnaceae family and grows all over the world, including Europe, North America, and Asia. Due to the vast geographic and morphological variety within Sambucus, there have historically been many species within the genus. However, a reorganization by Bolli reclassified some of the most common species under Sambucus into subspecies of S. nigra. More recently, elderberry was moved out of the Adoxoaceae family, which had already been changed before when elderberry was taken out of the Caprifoliaceae family. These changes have impacted the three subspecies most of interest in this work: the European elderberry S. nigra ssp. nigra; the American elderberry S. nigra ssp. canadensis; and the blue elderberry S. nigra ssp. cerulea . However, due to wide acceptance of this naming scheme for the subspecies, it will be used through this work to align with the current naming, but previous works cited may use the former species names. Furthermore, some sources refer to the entire plant as an “elder”, while others refer to the plant as “elderberry”, which is also used to denote the fruit of the plant. In this work, “elderberry” is used to discuss the plant as well as the fruit. “Elderflower” is used to refer to the blossoms of the plant. European elderberry is the most well-studied and widely used subspecies of elderberry in the market. This subspecies grows throughout the European continent, including countries such as Slovenia, Portugal, and Austria. The fruit and flower have been studied for decades for their composition and bioactivity, and while elderberry and elderflower are not new ingredients to the market, they have garnered more attention in the last several years as consumers look for more natural remedies and supplements to support their health.

This has been especially true during the COVID-19 pandemic, in which elderberry became a popular ingredient in immunity-supporting supplements. Thus, investigating other elderberry subspecies like the blue elderberry, the focus of future chapters, allows for farmers in the United States to capitalize on this demand, but more information is needed on this particular plant if it is going to be used in consumer products.There is a long, rich history of the use of different parts of the elderberry plant by many cultures. For example, the wood has been used for kindling and musical instruments. Indeed, the name of the plant is derived from various ancient words related to instruments. The flowers and berries have been used in a variety of beverages, foods, and other herbal supplements. Folklore has many stories about the healing power of the elderberry and elderflower. The plant itself has been revered by many cultures, with a story about the “Elder Mother” living within the plant would protect those near the plant. It was even expected to ask the Elder Mother for the berries or flowers before taking them; without permission, she may seek revenge. The leaves, branches, flowers, and berries were believed to have protective powers for a home and the leaves were also used during burial rituals by some Celtic people. The personification and deep reverence for the elderberry show the importance of the plant through generations. Hippocrates and Pliny the Elder both wrote about elderberry and its medicinal properties. Tribes indigenous to North America used flowers and fruit for medicinal and beverages. Berries were also used as a natural dye for baskets and branches were used to make musical instruments.Elderberry is a perennial, deciduous plant native to many regions of the northern hemisphere. Elderberry plants are neither tree nor bush, as the plant sends new canes up each season, which without pruning, can lead to a large, shrub-like plant that can be several meters tall and wide. They prefer to grow in sunny, riparian climates with moist, well-drained soil, though subspecies in North America can be drought-tolerant. While pruning even down to the ground level of the elderberry can improve yield and accessibility for harvesting, there is a limitation on pruning of the blue elderberry in the Central Valley of California. Due to the threatened status of the Valley Elderberry Longhorn Beetle , which lives only in the elderberry, branches larger than one inch in protected areas should not be pruned or removed from a growing site. Elderberry shrubs typically produce small white flowers with five petals in the spring, though the elder flowers of the blue elderberry are a creamy yellow color. Small, dark blue-purple berries ripen in the summer in large clusters called umbels or cymes, though there are examples of subspecies that have some variation to these morphologies, stackable flower pots such as the blue elderberry that has a white bloom on the berries, causing the berries to look blue, and S. racemosa, which are red. Variation can also occur within a subspecies due to growing conditions, such as soil type, precipitation, and temperatures, as well as a key differentiation tool: cultivars or genotypes. There are established cultivars or genotypes of the European subspecies , such as Sambu or Haschberg, as well as of the American subspecies , like Bob Gordon or Wylewood. Cultivars can have more consistent growing patterns, such as blooming or ripening all at once, and desired chemical compositions, such as increased anthocyanins, thus are more desirable to use in large scale growing of elderberry for commercial use. Blue elderberry does not have any established genotypes to date. If commercial interest inthis subspecies continues to expand, effort should be made to develop cultivars with consistent quality and improved harvestability, which is hampered right now due to flowers and berries ripening throughout a season, instead of a smaller window of time like the American and European subspecies. Indeed, starting this work can help increase the commercial interest viability of the blue elderberry.

A primary driver in interest in the composition of elderberry and elderflower is for their potential health benefits. Several reviews have recently been published on this topic; thus, it will not be explored in depth here. European elderberry has been studied for its antioxidant, antimicrobial, anti-inflammatory, anticancer, immunomodulatory, and antidiabetic properties, as well as neuroprotection and cardiovascular protection in vitro and in vivo. These activities have been mainly attributed to the phenolic compounds like cyanidin 3-glucoside and cyanidin 3- sambubioside, but some other compounds have been shown to be bioactive as well, including terpenes, lectins, pectin, peptides, and malic acid. 10,20 Using data from randomized, controlled clinical trials, a recent review found that elderberry could reduce symptoms from upper respiratory viral infections, providing support for the use of elderberry supplements by consumers to combat colds and flus without the use of antibiotic medicine. In a more unique application, elderberry and elderflower extracts have both shown to be effect in combatting gingival inflammation using a topical herbal patch and elderflower tea, respectively. A study of the mechanism of cyanidin 3-glucoside to treat against the influenza virus showed that elderberry extract had some inhibitory effect during the early stages of virus cycle with stronger impacts during post-infection. The mechanism proposed was that the elderberry extract blocks viral glycoproteins which prevent the virus from attaching or entering cells to replicate, and increases expression of IL-6, IL-8, and TNF. Inflammatory modulating activity of elderberry and elderflower extracts have been investigated. Results showed that quercetin, rutin, and kaempferol are strong inhibitors of nitric oxide production, and metabolites from phenolic degradation including caffeic acid and 3,4-dihydroxyphenylacetic acid were also strong inhibitors without cytotoxicity. Only a few studies have been done on the bioactivity of S. nigra ssp. canadensis. In one, the fruit was evaluated for anticancer properties, which showed chemo-preventative activity by inducing quinone reductase and inhibiting cyclooxygenase-2, as well as inhibiting ornithine decarboxylase. These activities are attributed to flavonoids and lipophilic compounds. Another study evaluated two Canadian cultivars of this subspecies evaluated the anti-proliferative efficacy of the fruit and flowers on glioma and brain endothelial cells and results showed that elderberry and elderflower extracts inhibited the proliferation of cells under normoxic and hypoxic conditions. The elderberry extracts performed the best and the bioactivities were attributed to the synergistic work of cyanidin 3-sambubioside-5-glucoside and rutin content of the berries, though the rutin concentration in the flowers still had beneficial effects. Blue elderberry has only been evaluated as antioxidant activity using the ABTS assay, which indicated that this subspecies has 11.62 ± 0.38 mM Trolox kg-1 FW, roughly one third of S. nigra ssp. nigra evaluated in the same study, where all fruit samples were grown in Slovenia. Further work on elucidating the biological activity of this subspecies through in vivo assays and preferably clinical trials should be explored, especially using blue elderberry plants growing in North America to support its use in supplements.Elder flowers have also been evaluated for their biological activities. A review of antioxidant activity in S. nigra ssp. nigra flowers has recently been published 2 , including ABTS, DPPH, FRAP and CUPRAC assays, therefore it will not be re-summarized here. In general, the data showed that elderflower has higher levels of antioxidant activity compared to the elderberry. Similarly, elderflower extracts had higher nitric oxide inhibition compared to elderberry extracts in vitro. Elderflower is antidiabetic by increasing insulin-dependent glucose uptake, diuretic, treat respiratory infections, antiviral. 10 While phenolic compounds like flavonols are presumed to be the most active compounds, pectic polysaccharides are also bioactive in elderberry and elderflower, inducing complement fixing and macrophage stimulation. Flowers of the blue elderberry have been evaluated for their antioxidant activity using the ABTS assay, which showed they have 44.87 ± 0.54 mM Trolox kg-1 DW, significantly less than flowers of S. nigra ssp. nigra . Aqueous extracts of wild elder flowers of this subspecies were also found to have neuroprotective effects, especially related to Parkinson’s disease, by increasing the antioxidant response mediated by Nrf2 in cortical astrocytes and improving mitochondrial function in neurons.