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Wildflowers attract wildlife, increase pollinator habitat, and enhance the aesthetic value of the landscape. Wildflower establishment is increasingly part of an effort to reduce maintained turfgrass on golf courses, lawns, and other maintained environments. Weed competition decreases wildflower establishment and results in poor long-term stands. Research was conducted in a controlled environment to investigate the tolerance of wildflower species to common postemergence herbicides. Wildflower species included California poppy (Eschscholzia californica Cham.), common sunflower (Helianthus annuus L.), cornflower (Centaurea cyanus L.), garden coreopsis (Coreopsis lanceolata L.), partridge pea [Chamaecrista fasciculata (Michx.) Greene], plains coreopsis (Coreopsis tinctoria Nutt.), purple coneflower [Echinacea purpurea (L.) Moench], rosering gaillardia (Gaillardia pulchella Foug.), and violet prairie clover (Dalea purpurea Vent.). Herbicides evaluated were fluazifop at 0.28 kg⋅ha–1 a.i., mesotrione at 0.14 kg⋅ha–1 a.i., clopyralid at 0.29 kg⋅ha–1 a.i., bentazon at 0.56 kg⋅ha–1 a.i., halosulfuron at 0.053 kg⋅ha–1 a.i., and imazaquin at 0.42 kg⋅ha–1 a.i. An untreated check was included for comparison. Excessive damage (≥ 53% phytotoxicity) was observed on all wildflower species in response to clopyralid, except for California poppy. Fluazifop and bentazon were relatively safe (≤ 19% phytotoxicity, regardless of herbicide) on all wildflower species; however, bentazon resulted in ≥ 40% aboveground biomass reduction in several species. Common sunflower and garden coreopsis were susceptible to halosulfuron (37% and 73% phytotoxicity, respectively) and imazaquin (37% and 87% phytotoxicity, respectively), but on all other wildflower species, phytotoxicity was ≤ 18%. Although both halosulfuron and imazaquin only resulted in ≤ 18% phytotoxicity to purple coneflower, a 43% to 44% aboveground biomass reduction was recorded. Mesotrione was only safe on California poppy and cornflower (≤ 11% phytotoxicity and ≤ 24% aboveground biomass reduction). Results suggest high tolerance variability across herbicides and species considered, but may prompt new investigation of safety and utility within field and production scenarios.
Spotted-wing drosophila (Drosophila suzukii; SWD) is an invasive pest in the United States that is responsible for significant economic damage to soft-skinned fruit and berries worldwide. SWD uses a wide variety of cultivated and wild fruit for reproduction. Host suitability may depend on physical and chemical factors of the fruit, with a positive correlation of SWD oviposition and larval development generally associated with soluble sugar content, softer fruit, and higher pH, and a negative correlation of oviposition with fruit firmness. Variety selection is an important tool for integrated pest management, but few studies have reported host suitability across varieties within a single cultivated crop species for SWD. In this study, we investigated SWD oviposition and larval development in five half-high blueberry cultivars, Chippewa, Northblue, Northland, Patriot, and Polaris, using no-choice and two-choice laboratory bioassays. Using a host potential index, our results showed that Chippewa was the most preferred cultivar for oviposition as measured in the number of eggs laid per fruit, and Polaris was the least preferred. The inverse was true for larval development, with a higher survival rate and adult emergence in ‘Polaris’ than in ‘Chippewa’. There was a negative relationship between fruit firmness and oviposition and a positive correlation between pH and larval development. The results of this study indicate that cultivar selection for half-high blueberries may be a promising integrated pest management (IPM) tool, although further research under field conditions is needed for validation.
The genus Capsicum has been distinguished by its lack of compatible rootstocks with commercial cultivars to successfully protect against Phytophthora capsici. Criollo de Morelos 334 (CM334) has been used worldwide in crosses and as a rootstock to protect against P. capsici. However, novel sources of resistance to this pathogen, such as ‘Pasilla 18M’ have not yet been explored as rootstocks. A good rootstock should be highly compatible with the scion and also maintain the quality and/or provide a benefit to the grafted cultivar. Our objectives were 1) to evaluate grafting survival using ‘Pasilla 18M’ and CM334 as rootstocks of two susceptible commercial cultivars: Sweet Pepper California Wonder (CW) and Serrano Coloso; and 2) to evaluate the efficiency of ‘Pasilla 18M’ as rootstock against P. capsici using CM334 as a resistant control. Grafting survival was analyzed over 58 days after grafting in sets of 60 plants per varietal combination. Disease severity and incidence were recorded during 24 days after inoculation with P. capsici (DAI). Incidence was also evaluated at 54 and 84 DAI. A severity scale from 0 (healthy plant) to 4 (dead plant) was applied to evaluate root rot per plant. Incidence was recorded as the percent of diseased plants (severity >0). Grafting survival of intervarietal grafts was 87% to 94%, similar to ungrafted cultivars, and exceeding autograft survival. Ungrafted and autografted Sweet Pepper and Serrano showed root rot severities 2.3 to 3.3, with 89% to 100% incidence. In contrast, intervarietal grafts remained almost free of infection (severity 0.14; incidence 0% to 4%). CM334 and ‘Pasilla 18M’ rootstocks are highly compatible with ‘Serrano Coloso’ and ‘Sweet Pepper CW’. ‘Pasilla 18M’ confers the same level of protection against P. capsici as CM334.
We investigated sugar (solute) accumulation in watermelon [Citrullus lanatus (Thunb.) Matsum. et Nakai] fruits at the immature stage. Watermelon plants were grown hydroponically in a nutrient solution with an electric conductivity (EC) of 1.2 S⋅m−1 (EC 1.2 regime); then, fruits were harvested 21 days after anthesis. The flesh of each fruit was divided into seven different parts to measure the sugar concentration and water status. The results indicated that the sugar concentration was higher in the center of the fruit flesh than in the other parts, such as around the pericarp. Moreover, the lowest osmotic potential was observed in the center of the fruit flesh, indicating solute accumulation. Concurrently, when the transport of photosynthates in the fruit was investigated using the 13CO2 isotope, the active solute accumulation in the center of the fruit flesh was observed, supporting the observed sugar accumulation in this part. Consequently, this active solute accumulation and distribution occurred in the center of the watermelon fruit, as demonstrated by the data of osmotic pressure and sugar concentration and supported by the observed active photosynthate accumulation. Additionally, we investigated these measurements by increasing the nutrient solution concentration 14 days after anthesis. As a result, fruit growth was slightly inhibited using the EC 3.0 regime, and 13C translocation was also inhibited in the fruit, especially in its center. Even though the sugar concentration and osmotic pressure of the fruit flesh were not clearly affected by high nutrient solution concentrations, the cell turgor of the central flesh of the fruit grown using the EC 2.0 and 3.0 regimes was lower than that of the fruit grown using the EC 1.2 regime. Treatments with higher nutrient concentrations might have negative effects on immature watermelon fruits.
Crapemyrtle bark scale (CMBS; Acanthococcus lagerstroemiae Kuwana), a fast-spreading invasive insect, has been causing damage to popular landscape plants in at least 17 states in the United States since 2004. This invasive insect has a list of documented plant hosts in ∼23 genera, which includes its primary hosts, crapemyrtles (Lagerstroemia spp.), as well as other important plant species, such as pomegranates, apple, and the native plant American beautyberry. Previous studies have shown CMBS causes different levels of feeding damage among its plant hosts, while the underlining plant defense mechanisms toward CMBS attacks remain elusive. A better understanding of plant–CMBS interactions and how CMBS performs under different plants (e.g., a susceptible vs. a resistant host) can provide valuable guidance for integrated pest management. Therefore, in this study, we conducted the age-stage, two-sex table study analysis to evaluate the biological parameters of CMBS on different species or cultivars of crapemyrtle under laboratory conditions (25 °C and 250 μmol·m−2·s−1 light with a photoperiod of 12 hours:12 hours (light:dark). Crapemyrtle bark scale development was found to be greatly influenced by the hosts. This study aims to provide important biological and ecological data on CMBS using a comprehensive life table study to gain a thorough understanding of its development, survival, and fecundity on different crapemyrtle species or cultivars.
Open-pollinated seeds from grapevines in Parlier and Davis (in California) and Geneva (in New York) were collected in 2016, 2017, and 2018. Seeds were subjected to a series of cold stratification treatments of varying lengths and germinated in incubators to compare germination rates. Two V. vinifera cultivars (Chardonnay and Cabernet Sauvignon) and three other cultivars (V. labrusca hybrids) with a similar genetic background were compared across three locations to test for maternal environmental effects on germination rates under different cold stratification durations. Two interspecific hybrids (‘Salamander’ and ‘Sovereign Rose’) and three genotypes each from two species, V. riparia and V. cinerea, were evaluated to compare germination rate variability at different cold stratification durations among and within species and hybrids. Large variability in germination rates was evident among and within grape species, with some accessions requiring little to no cold stratification, and others requiring 10 to 12 weeks. These differences could be useful for breeding grapevines with high or low dormancy requirements. The maternal plant environment impacted the seed weight and total seed germination across years and locations.
An online survey of plant purchasers was conducted to ascertain the influence of plant benefits messaging on consumer behavior. Three plant attributes, including type of plant, price, and plant availability, were used to distinguish purchasing preferences. To assess plant purchasing behavior, participants viewed a list of 12 different plant types and selected those they had purchased in the past year. The 12 plant types included annuals, vegetables, herbs, perennials, flowering shrubs, evergreen shrubs, fruit trees, evergreen trees, shade trees, flowering plants, foliage plants, and succulents. The most common retail locations patronized for plant purchases were home improvement stores, closely followed by independent garden centers. Consumers were grouped according to eight different plant benefit messages that they were exposed to, including physical, emotional, cognitive, social, educational, environmental, financial, and aesthetic benefits. Although some of the groups (clusters) exhibited similar purchasing behaviors in terms of plant types purchased, price levels preferred, and their preference for rare, common, or moderately available plants, there were just enough differences among groups to be able to distinguish them from other groups. The plant benefits were obviously affecting purchasing behavior, but further study is needed to understand the underlying reasons more fully.
Anthocyanins are a group of human-health-promoting phenolic compounds that influence the pigmentation of red-leaf lettuce (Lactuca sativa). Ultraviolet A (UVA; 315–399 nm) and blue (B; 400–499 nm) light can increase the concentrations of phenolic compounds but also suppress cellular expansion, which can limit harvestable biomass accumulation. It is not known whether UVA or B light is more effective at increasing phenolic compound concentrations when they are each applied at the same photon flux density. Our objective was to evaluate the efficacy of UVA and B light when added during the end of production (EOP) at promoting phenolic compound synthesis and red-leaf coloration without limiting biomass accumulation. We grew red-leaf lettuce ‘Rouxai’ in a controlled indoor environment at an air temperature of 22 °C under warm-white and red light-emitting diodes (LEDs). On day 24, 30 or 60 µmol·m−2·s−1 from UVA, B, UVA plus B, or red plus green LEDs was added during the last 6 days of the 30-day production period. UVA and B light, alone or combined, similarly increased leaf redness (by up to 72%), total phenolic concentration (by up to 92%), total anthocyanin concentration (by up to 2.7-fold), and relative chlorophyll concentration (by up to 20%) and did not inhibit growth, compared with lettuce grown without EOP supplemental lighting. Considering B light was as effective as UVA light at increasing leaf color and phytonutrient density and that B LEDs are more electrically effective, economical, and durable, an enriched blue-light spectrum at the EOP is a comparatively sustainable method to increase crop quality without suppressing biomass accumulation.