The Desert Whale: the boom and bust of hemp in Arizona.

BACKGROUND: This paper examines the factors that led to the collapse of hemp grown for cannabidiol (CBD) in Arizona, the United States of America (USA), and particularly in Yuma County, which is a well-established agricultural area in the state. METHODS: This research uses a combination of mapping analysis along with a survey of hemp farmers to assess the reasons why the hemp industry collapsed as well as to foster solutions to these problems. RESULTS: In 2019, 5430 acres were sown with hemp seed in Arizona with 3890 acres inspected by the state to determine if they could be harvested. By 2021, there were only 156 acres planted, and only 128 of those acres were inspected by the state for compliance. (Crop mortality accounts for the difference between acres sown and acres inspected.) CONCLUSIONS: A lack of knowledge about the hemp life cycle greatly contributed to the failure of high CBD hemp crops in Arizona. Other problems included noncompliance with tetrahydrocannabinol limits, poor sources for seeds and inconsistent genetics of the hemp varieties sold to farmers, and diseases that hemp plants were susceptible to such as Pythium crown and root rot and beet curly top virus. Addressing these factors will go far in making hemp a profitable and widespread crop in Arizona. Additionally, hemp grown for other traditional uses (e.g., fiber or seed oil) as well as new applications (e.g., microgreens, hempcrete, and phytoremediation) offers other pathways for successful hemp agriculture in this state.

First Report of Crown and Root Rot Caused by Pythium aphanidermatum on Industrial Hemp (Cannabis sativa) in Arizona.

During July and August 2020, symptoms of leaf yellowing and browning, sudden wilting, and death were observed on industrial hemp plants (Cannabis sativa L.) in several drip-irrigated fields in Yuma and Graham county, Arizona. About 85% of plants showed severe crown and root rot symptoms. A high percentage of affected plants collapsed under intensive heat stress. Shriveled stem tissue with necrotic lesions can often be seen at the base of the plant, extending upwards more than 5 cm. Internal tissue of main stem and branches was darkened or pinkish brown. Outer cortex of root bark was often completely rotten, exposing the white core. Cottony aerial mycelium was visible on the surface of stalk of some of the infected plants in two fields in Yuma. To identify the causal agent, a total of twenty symptomatic plants were collected from several fields across the state. Crown and root tissues from affected plants were harvested and rinsed in tap water to remove soils. Approximately 2 to 4 mm tissue fragments were excised from the margins of the affected stem and root lesions, surface sterilized in 0.6% sodium hypochlorite for 1 min, rinsed copiously in sterile distilled water, blotted dry, and plated on potato dextrose agar (PDA), and on oomycete-selective clarified V8 medium containing pimaricin, ampicillin, rifampicin, and pentachloronitrobenzene (PARP). Plates were incubated at room temperature for 2 days. Sixteen isolates were recovered and their mycelial colonies resembled the morphology of Pythium. Based on the culture morphology on V8 medium, all isolates were tentatively identified as P. aphanidermatum with fast-growing, aseptate hyphae ranging from 3 to 7 µm in width, globose oogonia ranging from 25 to 31 µm in diameter, barrel-shaped antheridia, globose oospores ranging from 15 to 21 µm in diameter (10 measurements) (Watanabe, 2002). Genomic DNA was extracted from mycelial mats of three isolates using DNeasy Plant Pro Kit (Qiagen Inc., Valencia, CA) according to the manufacturer's instructions. The internal transcribed spacer (ITS) region of rDNA was amplified with primers ITS1/ITS4 and three nucleotide sequences were obtained. All three sequences were identical and deposited under accession number MW380253 in GenBank. A BLASTn search revealed that MW380253 had a 100% query coverage and 100% match with sequences MK611609.1, KJ162355.1, and AY598622.2, obtained from isolates of P. aphanidermatum. To fulfill Koch's postulates, pathogenicity tests were conducted with 2 isolates using 12 seeds of a hemp line 14 sown in 12 1.9-liter pots filled with a steam-disinfested potting mix. Pots were placed in a plastic container and watered three times a week by flooding, to create waterlogged conditions. Plants were maintained in a greenhouse supplemented with artificial lighting of 14 h/10 h day/night light cycle. Plants were fertilized weekly with a 20-20-20 fertilizer at 1mg/ml. Three weeks after sowing, four plants were inoculated with each isolate by drenching each plant with 200 ml of a 1×105 zoospore/ml suspension. Four plants, serving as control, received each 200 ml of distilled water. Symptoms of leaf chlorosis, crown and root rot, and wilting were observed 3 weeks afterwards, while control plants remained asymptomatic. P. aphanidermatum were re-isolated from necrotic roots of inoculated plants, but not from control plants. P. aphanidermatum was previously detected on industrial hemp in a research plot in Indiana (Beckerman et al., 2017) and is also known to affect other crops in Arizona during the summer months as well (Olsen & Nischwitz, 2011). This report is the first publication documenting P. aphanidermatum on field grown hemp in Arizona. Industrial hemp (Cannabis sativa) is an emerging crop in Arizona. The first plantings of hemp were in June of 2019, where 5,430 acres of hemp was planted in thirteen counties in Arizona before the end of the year. The Arizona Department of Agriculture Industrial Hemp Program, 2019 Year End Report confirms that nearly one-quarter of all hemp planted in 2019 did not receive a final state inspection due to crop loss. This disease is a potential constraint to hemp production in hot, arid climates, where copious water is used in combination with plastic mulch and/or drainage is poor.

First Report of Beet Curly Top Virus Infecting Industrial Hemp (Cannabis sativa) in Arizona.

Industrial hemp (Cannabis sativa) is an emerging crop in Arizona, with many uses, including fiber, cosmetic products, and health food. In 2020, severe curly top disease outbreaks were observed in several hemp fields in Yuma and Graham Counties, Arizona, where disease incidence and severity were considerably high, up to 100% crop loss occurring in some fields. A wide range of symptoms have been observed at different infection stages and plant growth stages at the time of infection. Early stage symptoms manifest as light green-to-yellowing of new growth, similar to sulfur or micronutrient deficiency, usually combined with older leaves with dark green "blotchy" mosaic mottling overlaying light green chlorosis. Mosaic mottling of older leaves continues into mid-growth stage, and is coupled with more severe yellowing and witch's broom (stunted leaves and shortened internode length of stem) of apical meristematic tissue. Curling and twisting of new leaves has also been observed. Symptoms often appear to be isolated to individual branches, with other branches showing no visual symptoms, often outgrowing and covering affected branches until harvest. Late stage symptoms include severe leaf curling with or without twisting, continued stunting, and necrosis of yellow leaves, resulting in significant yield reduction. Severely affected plants dwarfed by the virus experienced high mortality rates later into the season, most likely attributed to reduced ability to overcome abiotic stress conditions. These symptoms indicated the likelihood of curly top caused by Beet curly top virus (BCTV), which has been recently reported in Colorado (Giladi et al., 2020). Shoots were collected from thirty-eight symptomatic and nine asymptomatic hemp plants from July to August, 2020. Leaves were also collected as positive control from four chili pepper plants with or without curly top symptoms in Cochise County. Genomic DNA was extracted using DNeasy Plant Pro Kit (Qiagen Inc., Valencia, CA) according to the manufacturer's instructions. BCTV-specific primers BCTV1 and BCTV2 were used to detect BCTV following a method by Rondon (Rondon et al., 2016). A 500 bp DNA fragment, indicative of BCTV, was amplified from all symptomatic hemp and chili pepper samples, but not from asymptomatic samples. Sequence analysis of this 500 bp DNA fragment revealed 98.99 % identity with GenBank accession MK803280, which is Beet curly top virus isolate from hemp identified in Western Colorado (Giladi et al., 2020). The full-length genomes of BCTV isolates from hemp and chili peppers were generated with additional primers 328F/945R (620bp), 455F/ 945R (490bp), OutR/ 2213F (1,190bp), 2609R/ 1278R (1,340bp), BCTV2/ 2609R (1,890bp) (Rondon et al., 2016, Strausbaugh et al., 2008). The complete nucleotide sequence (MW182244) from hemp was 2,929 bp and had 99.35% sequence identity with GenBank accession KX867055, which was a Worland strain of Beet curly top virus isolated from an Idaho sugar beet plant (Strausbaugh et al., 2017). Our hemp BCTV genome sequences shared 96.08% identity with the hemp strain of BCTV from Colorado (MK803280) and 99.50% identity with the BCTV isolate (MW188519) from chili pepper identified in this study. BCTV was reported on outdoor hemp in Western Colorado, in 2020 (Giladi et al., 2020). This is the first report of BCTV in Arizona causing curly top of industrial hemp in the field. In Arizona, BCTV is widespread on many agronomic crops including chili peppers and spread primarily by the phloem-feeding beet leafhoppers: Circulifer tenellus (Hemiptera: Cicadellidae) (Bennett, 1967). Due to the wide distribution of beet leafhoppers and abundant range of host plants for the virus, BCTV may become one of the most yield-limiting factors affecting the emerging industrial hemp production systems in Arizona.

Physical and Physiological Determinants of Rock Climbing.

PURPOSE: Rock climbing performance relies on many characteristics. Herein, the authors identified the physical and physiological determinants of peak performance in rock climbing across the range from lower grade to elite. METHODS: Forty four male and 33 female climbers with onsight maximal climbing grades 5a-8a and 5a-7b+, respectively, were tested for physical, physiological, and psychological characteristics (independent variables) that were correlated and modeled by multiple regression and principal component analysis to identify the determinants of rock climbing ability. RESULTS: In males, 23 of 47 variables correlated with climbing ability (P < .05, Pearson correlation coefficients .773-.340), including shoulder endurance, hand and finger strength, shoulder power endurance, hip flexibility, lower-arm grip strength, shoulder power, upper-arm strength, core-body endurance, upper-body aerobic endurance, hamstrings and lower-back flexibility, aerobic endurance, and open-hand finger strength. In females, 10 of 47 variables correlated with climbing ability (P < .05, Pearson correlation coefficients .742-.482): shoulder endurance and power, lower-arm grip strength, balance, aerobic endurance, and arm span. Principal component analysis and univariate multiple regression identified the main explanatory variables. In both sexes, shoulder power and endurance measured as maximum pull-ups, average arm crank power, and bent-arm hang, emerged as the main determinants (P < .01; adjusted R2 = .77 in males and .62 in females). In males, finger pincer (P = .07) and grip strength also had trends (P = .09) toward significant effects. Finally, in test-of-principle training studies, they trained to increase main determinants 42% to 67%; this improved climbing ability 2 to 3 grades. CONCLUSIONS: Shoulder power and endurance majorly determines maximal climbing. Finger, hand, and arm strength, core-body endurance, aerobic endurance, flexibility, and balance are important secondary determinants.

A regional assessment of white-tailed deer effects on plant invasion.

Herbivores can profoundly influence plant species assembly, including plant invasion, and resulting community composition. Population increases of native herbivores, e.g. white-tailed deer (Odocoileus virginianus), combined with burgeoning plant invasions raise concerns for native plant diversity and forest regeneration. While individual researchers typically test for the impact of deer on plant invasion at a few sites, the overarching influence of deer on plant invasion across regional scales is unclear. We tested the effects of deer on the abundance and diversity of introduced and native herbaceous and woody plants across 23 white-tailed deer research sites distributed across the east-central and north-eastern USA and representing a wide range of deer densities and invasive plant abundance and identity. Deer access/exclusion or deer population density did not affect introduced plant richness or community-level abundance. Native and total plant species richness, abundance (cover and stem density) and Shannon diversity were lower in deer-access vs. deer-exclusion plots. Among deer-access plots, native species richness, native and total cover, and Shannon diversity (cover) declined as deer density increased. Deer access increased the proportion of introduced species cover (but not of species richness or stem density). As deer density increased, the proportion of introduced species richness, cover and stem density all increased. Because absolute abundance of introduced plants was unaffected by deer, the increase in proportion of introduced plant abundance is likely an indirect effect of deer reducing native cover. Indicator species analysis revealed that deer access favoured three introduced plant species, including Alliaria petiolata and Microstegium vimineum, as well as four native plant species. In contrast, deer exclusion favoured three introduced plant species, including Lonicera japonica and Rosa multiflora, and 15 native plant species. Overall, native deer reduced community diversity, lowering native plant richness and abundance, and benefited certain invasive plants, suggesting pervasive impacts of this keystone herbivore on plant community composition and ecosystem services in native forests across broad swathes of the eastern USA.

Intervertebral Micro Access Surgery for Transforaminal Lumbar Interbody Fusion.

BACKGROUND: Minimally invasive spine surgery (MIS) has undergone tremendous progress in the past 2 decades. The intervertebral micro access surgery (iMAS) technique represents a hybrid of both open and minimally invasive techniques. OBJECTIVE: To describe the surgical technique and operative nuances of the iMAS technique. METHODS: We describe a novel operative approach for the standard transforaminal lumbar interbody fusion with pedicle screw fixation. Described are the preoperative planning, incision and approach, pedicle screw insertion, facetectomy and discectomy, transforaminal interbody placement, and direct decompression. RESULTS: Early experience suggests that iMAS is well suited for the same degenerative conditions currently treated with open or MIS transforaminal lumbar interbody fusion, including grade I spondylolisthesis, unilateral synovial cysts with instability, unilateral disc herniations with instability, and recurrent disc herniations. CONCLUSION: The novel integration of both open and MIS techniques makes iMAS an attractive approach for select degenerative lumbar disease processes. Similar to other MIS procedures, minimal tissue disruption may allow for more rapid patient recovery, reduced blood loss, and reduced length of hospital stay.