The issue of native invasive species management rarely occurs and is fraught with biological, social, and economic challenges as well as posing difficulties in decision-making for land managers. The terminology for categorization of invasive species is examined in the context of their bias(es), which complicates control. An example of a newly determined native species, which is also invasive, is used as an example to navigate control and regulatory issues. Native, invasive reed canarygrass (Phalaris arundinacea L.) occurs throughout Minnesota and most likely the entire midwest region of central United States and Canadian provinces. The species was previously assumed to be an exotic, nonnative Eurasian import but recent molecular evidence supports its status as a native but invasive species. We address how this change to being a native but highly invasive species modifies approaches to mitigate its potential control for state, Tribal, and local authorities. The implications of these new findings will require differential shifts in land managers’ perspectives and approaches for control. Particular differences may exist for Tribal Land Managers vs. departments of natural resources and private agencies. Additionally, regulatory challenges have yet to be decided on how to legislate control for a native invasive species that had been previously assumed as exotic or foreign in origin. These opportunities to change attitudes and implement judicial control measures will serve as a template for other invasive species that are native in origin.
Neil O. Anderson, Alan G. Smith, Andrzej K. Noyszewski, Emi Ito, Diana Dalbotten, and Holly Pellerin
Michael A. Schnelle and Lyn A. Gettys
Irfan Ali Sabir, Xunju Liu, Songtao Jiu, Matthew Whiting, and Caixi Zhang
Sweet cherry (Prunus avium L.) is a valuable fruit crop worldwide. Farmers’ incomes are closely related to fruit quantity and quality, yet these can be highly variable across years. As part of a broader project for optimizing fruit set and fruit quality in sweet cherries, this study was conducted to evaluate the potential of various plant growth regulators (PGRs) for improving fruit set and fruit quality. Cytokinins, gibberellins, auxin, and polyamines were used as treatments. Treatments were applied as foliar sprays at full bloom to ‘Bing’ and three low-productivity genotypes, ‘Regina’, ‘Tieton’, and ‘PC8011-3’. We assessed the fruit set, fruit quality, and return bloom from each treatment. 4-chlorophenoxyacetic acid (4-CPA) increased fruit set by 53% and 36% in ‘Bing’ and ‘Tieton’, respectively. The combination of gibberellin (GA)3 + GA4/7 was more effective for improving fruit set than other isomers of gibberellin alone. Cytokinin treatments had slight adverse effects or no effect on fruit set except for CPPU. In ‘PC8011-3’, both N-(2-chloro-4-pyridyl)-N'-phenylurea (CPPU) and 4-CPA enhanced fruit set by ≈81% and 100% compared with untreated control. The response of cherry trees to polyamine sprays depended on the properties of the cultivars and the treatment concentration. Foliar application of GA3, GA4/7, or N-phenyl-N'-(1, 2, 3-thiadiazol-5-yl) urea (TDZ) in ‘Bing’ trees has negative effects on return bloom, whereas GA1 can increase the yield and flower buds. These results suggest that PGRs may have varied effects on sweet cherry fruit set and that more work is needed to develop practical programs for improving yield security.
Wenjing Li, Zihang Zhang, Ji Tian, Jie Zhang, Yanfen Lu, Xiaoxiao Qin, Yujing Hu, and Yuncong Yao
Ravneet K. Sandhu, Nathan S. Boyd, Lincoln Zotarelli, Shinsuke Agehara, and Natalia Peres
Vegetable growers in Florida face rising production costs, reduced crop value, and competition from foreign markets. Relay cropping is a variant of double cropping, where the second crop is planted into the first crop before the harvest is finished. This cropping system may be a potential solution to lower production costs per crop by sharing some inputs for two crops. The objectives of this study were to determine the effect of cropping sequence and transplanting date of the secondary crop when relay cropping tomato and bell pepper. Two field experiments were conducted at the Gulf Coast Research and Education Center in Balm, FL, in 2018 and 2019. In the first experiment, tomato was grown as the primary crop and bell pepper was added as the secondary crop, with multiple transplanting dates (8 Aug., 23 Aug., 7 Sept., and 24 Sept.). The second experiment had the same setup but the reverse cropping sequence. Bell pepper yield as the secondary crop was reduced by 65% when grown with tomato as the primary crop compared with bell pepper planted alone. Transplanting date had no effect on bell pepper yield (P = 0.091). Tomato yield was unaffected by the presence of the secondary crop. In the second experiment, tomato yield as a secondary crop was 36% lower when grown with bell pepper as the primary crop compared with tomato crop alone (monocropped). However, tomato yield was significantly reduced by the presence of bell pepper only when tomato crop was planted within 30 to 45 days after planting bell pepper. Based on these results, we recommend relay cropping tomato as the secondary crop within 30 days of planting of bell pepper as the primary crop. However, we do not recommend relay cropping bell pepper as the secondary crop with tomato.
Florence Breuillin-Sessoms, Dominic P. Petrella, Daniel Sandor, Samuel J. Bauer, and Brian P. Horgan
Consumers often have multiple choices when purchasing retail lawn products in stores. In this study, we evaluated the acute drought performance of locally available retail lawn seed products (mixtures or blends) at two mowing heights of 2.5 and 3 inches. We hypothesized that the species present in the products and the height-of-cut differentially influence the drought resistance and recovery of the mixtures and blends. In Fall 2016 and 2017, 28 different products consisting of 25 mixtures and 3 blends of turfgrass seeds were established under a fully automated rainout shelter at the St. Paul campus of the University of Minnesota. The drought treatments lasted for 67 days in 2017, and 52 days in 2018; both the 2017 and 2018 treatments were followed by a recovery period. Data were obtained during acute drought treatments and recovery periods for visual turfgrass quality and green turfgrass cover using digital images of the plots. During the first year, several products displayed higher green stability (or the ability to remain green) at the 3-inch height-of-cut compared with the 2.5-inch height-of-cut. Products with tall fescue (Schedonorus arundinaceus) and fine fescue (Festuca sp.) as dominant species generally performed better during the drought treatments, whereas an increasing presence of perennial ryegrass (Lolium perenne) and kentucky bluegrass (Poa pratensis) decreased the visual drought performance of the products. During the recovery period, an effect of the interaction between mowing height and the date of data collection on the percentage of green cover was observed: the lower mowing height improved the early recovery of green cover after acute drought. These findings suggest that consumers in the upper midwestern United States and areas with a climate similar climate to that of St. Paul, MN, who are challenged with multiple choices of lawn seed products should choose products containing a higher tall fescue content and adjust their mowing heights to optimize recovery.
Laban K. Rutto, Yixiang Xu, Shuxin Ren, Holly Scoggins, and Jeanine Davis
‘Hop’ (Humulus lupulus) cultivar trials were conducted at sites in three Virginia counties (Northampton, Chesterfield, and Madison) in response to demand by the craft beer industry for local ingredients. In 2016, a replicated study involving five cultivars (Cascade, Chinook, Newport, Nugget, and Zeus) was established on an 18-ft-tall trellis system at each site. Weather data influencing infectivity of downy mildew (Pseudoperonospora humuli) and powdery mildew (Podosphaera macularis), two economically important hop diseases, was collected, and to the extent possible, similar cultural practices were applied at each site. Climatic conditions favorable to P. humuli and P. macularis were present throughout the experimental period, and P. humuli infection was widespread at all sites starting from 2017. Among common pests, Japanese beetle (Popillia japonica) was the only one observed to cause significant damage. Unseasonably high rainfall in 2018 led to crop failure at all but the Northampton site, and harvesting was done at all sites only in 2017 and 2019. Yields (kilograms per hectare by weight) in 2017 were found to be ≥45% lower than second-year estimates for yards in the north and northwestern United States. Quality attributes (α and β acids; essential oil) for cones harvested from the Chesterfield site were comparable to published ranges for ‘Cascade’ in 2019, but lower for the other cultivars. More work is needed to identify or develop cultivars better suited to conditions in the southeastern United States. The influence of terroir on quality of commercial cultivars produced in the region should also be examined.
Michael A. Schnelle
Four ornamental species, lyreleaf salvia (Salvia lyrata), roughleaf dogwood (Cornus drummondii), northern sea oats (Chasmanthium latifolium), and cholla (Cylindropuntia imbricata), are all native to Oklahoma and nearby states. They all possess ornamental attributes and range from widespread to niche crops in the nursery industry and are also cultivated for their utilitarian, herbal, and miscellaneous merits. Their allure to customers and their ability to thrive in a myriad of environments is a major impetus for commercial growers and retailers to carry these species. However, their extraordinary ability to adapt to a plethora of environmental conditions, in the built environment or in their native range, also enables them to often outcompete neighboring flora. Their predisposition to be opportunistic, and ability to grow in challenging locations, sometimes results in their becoming a nuisance or even invasive (i.e., capable of displacing other native flora or fauna). Plants featured are described for their marketable attributes but also reviewed for control measures (e.g., herbicides, prescribed burning, improved grazing practices) when they grow in an aggressive manner.
Sandra B. Wilson, Julia Rycyna, Zhanao Deng, and Gary Knox
Over the course of nearly 2 decades, the resident or wild-type form of heavenly bamboo (Nandina domestica) and 25 additional selections have been evaluated for landscape performance and invasive potential in various trial locations in Florida. Overall, in northern Florida (Quincy and Citra), ‘Royal Princess’, ‘Umpqua Chief’, ‘Gulf Stream’, ‘Monfar’ (Sienna Sunrise®), ‘Emerald Sea’, ‘Greray’ (Sunray®), ‘Lemon-Lime’, ‘Murasaki’ (Flirt™), ‘SEIKA’ (Obsession™), and ‘Twilight’ performed well throughout much of the study with average ratings between 3.0 and 4.9 (1 to 5 scale). In southern Florida (Balm and Fort Pierce), ‘AKA’ (Blush Pink™), ‘Compacta’, ‘Emerald Sea’, ‘Firestorm’™, ‘Greray’, ‘Gulf Stream’, ‘Harbour Dwarf’, ‘Jaytee’ (Harbor Belle™), ‘Lemon-Lime’, ‘Monum’ (Plum Passion®), ‘Murasaki’, and ‘SEIKA’ performed well with average ratings between 3.0 and 5.0. Among selections evaluated, plant sizes were categorized as small, medium, or large, where the final plant height ranged from 20 to 129 cm, and the plant perpendicular width ranged from 15 to 100 cm. Almost three-fourths of the selections evaluated had little to no fruiting when compared with the wild-type form. ‘AKA’, ‘Chime’, ‘Filamentosa’, ‘Firehouse’, ‘Firepower’, ‘Firestorm’, ‘Greray’, ‘Lemon- Lime’, ‘Moon Bay’, and ‘SEIKA’ did not fruit at any of the trial sites. In northern Florida, small amounts of fruit (94% to 99.9% reduction) were observed for ‘Gulf Stream’, ‘Harbour Dwarf’, ‘Jaytee’, ‘Monfar’, ‘Murasaki’, ‘Royal Princess’, ‘Twilight’, and the twisted leaf selection. Moderate amounts of fruit (62% to 83% reduction) were observed for ‘Alba’, ‘Emerald Sea’, ‘Lowboy’, ‘Moyer’s Red’, and ‘Umpqua Chief’. Heavy fruiting comparable or greater than the wild type was observed for ‘Compacta’ and ‘Monum’. Pregermination seed viability ranged from 67% to 100% among fruiting selections with 5.5% to 32.0% germination in 60 days. Germination was considerably higher (58% to 82%) when the germination time was extended to 168 days. Nuclear DNA content of selections were comparable to the wild type suggesting they are diploid. Thus, ploidy level does not appear to be associated with female infertility of those little-fruiting heavenly bamboo selections. Overall, our findings revealed certain selections of heavenly bamboo that have little potential to present an ecological threat and thus merit consideration for production and use. As a result, the University of Florida(UF)/Institute of Food and Agricultural Sciences’ (IFAS) Status Assessment on Non-native Plants in Florida’s Natural Areas infraspecific taxon protocol has concluded that ‘Firepower’ and ‘Harbour Dwarf’ are noninvasive and can be recommended for production and use in Florida. In addition, due to acceptable plant performance and low to no fruiting capacity, our research supports that ‘Firehouse’, ‘AKA’, ‘Firestorm’, ‘Gulfstream’, ‘Jaytee’, ‘Monfar’, ‘Royal Princess’, ‘Greray’, ‘Lemon-Lime’, ‘Murasaki’, and ‘SEIKA’ be considered for future noninvasive status approval.
Chia-Hsun Ho, Man-Hsia Yang, and Huey-Ling Lin
The volatile profile of the edible vegetable Gynura bicolor [Gynura bicolor (Roxb. ex Willd.) DC] was analyzed using gas chromatography-mass spectrometry (GC-MS). Isocaryophyllene (23.2%), α-pinene (16.8%), α-humulene (9.1%), β-pinene (7.3%), and copaene (7.0%) were identified as the major compounds in the leaves. In the stems, α-pinene (27.1%), β-pinene (13.0%), isocaryophyllene (7.8%), β-myrceneb (7.8%), 1-undecene (5.7%), and copaene (5.3%) were the main components. G. bicolor grows best at 25 °C. When cultivated at different temperatures (20 to 35 °C in incements of 5 °C), the volatile profiles shifted. The proportion of isocaryophyllene was lower at 20 °C than at the other temperatures. The relative amounts of α-pinene and α-humulene were highest at 20 °C, whereas copaene was highest at 35 °C. Principal component analysis (PCA) was used to explore the correlation between volatile compounds identified from the vegetative tissues and temperature treatments. It reveals the same trend with the previous statements and the first principal component (PC1) and the second principal component (PC2) explains up to 90% of the variance. Experimental results revealed that both temperature and vegetative organ correlate with the volatile emission profile of G. bicolor.