Papers presented at IPPS-SRNA Annual Meeting in Mobile, Alabama, Oct. 23- 27, 2021

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Technical Sessions of International Plant Propagators’ Society-Southern Region of North America (SRNA) Annual Meeting

Author: Brie Arthur

The 45th Annual Meeting of the International Plant Propagators’ Society-Southern Region of North America (SRNA) convened at 8:00 am on 25 October 2021 at the Renaissance Mobile Riverview Plaza Hotel, Mobile, Alabama, with President Brie Arthur presiding.

Keywords: Annual Meeting, Southern Region of North America (SRNA)

Keeping Consumer Demand High: Riding the Green Wave of the COVID-19 Garden Explosion

Author: Heather Kirk-Ballard

During the Covid-19 pandemic as the nation enforced a precautionary lockdown to help prevent the spread of infection, many households became restless. While other businesses were experiencing hardships because of shutdowns, the green industry was in high demand with many reporting significant gains in sales and profits. Garden stores reported greatly increased sales of vegetable crops, edibles, seeds and gardening supplies. The Cooperative Extension Service also experienced an dramatic increase in requests for information on home gardening. In the 2018 National Garden Survey conducted by the Garden Media Group, 12 million Americans said, “I’m too busy to have much time for gardening” (Garden Media Group, 2018). Now with time on their hands, Americans began gardening in droves - and this is good news for the green industry!

Keywords: Covid-19, home gardening, green industry, new gardeners, increased plant demand, increased sales.

“To Eat, or Not to Eat, That is the Question” - Answered by Real-Time Monitoring Techniques

Author: Bin Wu, Elizabeth Chun, Runshi Xie, Gary W. Knox, Mengmeng Gu, Hongmin Qin

“To Eat, or Not to Eat, That is the Question” - Answered by Real-Time Monitoring Techniques Combining with Computational Analysis for Feeding Behavior Study of Crapemyrtle Bark Scale (Acanthococcus lagerstroemiae)

Crapemyrtle bark scale [(CMBS) Acanthococcus lagerstroemiae], an invasive and polyphagous sap feeder, has spread across 17 U.S. states. The infestation of CMBS negatively impacts the flowering and fruiting of various ornamental and fruit plants. Crapemyrtle bark scale host confirmation is critical to determine the insect's potential risks to the Green Industry and help develop strategic management of CMBS. Previously confirming CMBS hosts was time-consuming. We investigated the CMBS feeding activities using the electrical penetration graph (EPG) to monitor real-time stylet penetration to determine potential hosts more efficiently. First, we characterized typical EPG waveforms (waveform C, waveform potential drop, the total duration of E1 and E2, and total duration of waveform G) of feeding activities for CMBS on a validated host, Lagerstroemia limii. We then tested the feeding behavior of CMBS using different species, including L. speciosa, L. indica 16√ó" style="width: 8pt; height: 14pt;"> speciosa ‘18096’, Mexican beautyberry (Callicarpa acuminata), three Ficus species (F. pumila, F. tikoua, and F. auriculata), and soybean (Glycine max), with the positive control (L. limii). Results showed that plant species significantly impacted phloem sap ingestion of CMBS, which could be used to rapidly confirm a a potential CMBS host.

Keywords: Data mining, electrical penetration graph, sap-sucking hemipteran, stylet penetration

Evaluation of Surfactants for Use in One-Time Foliar Auxin Applications in the Propagation of Woody Ornamentals

Author: Anthony T. Bowdena, Patricia R. Knight, Christine E.H. Coker, Jenny B. Ryals, Scott A. Langlois, Shaun R. Broderick, Eugene K. Blythe, Hamidou F. Sakhanokho, and Ebrahiem M. Babiker.

Use of foliar applications are increasing in the nursery and greenhouse industries. However, previous research has shown that insufficient auxin is being absorbed or translocated to the site of action. Addition of surfactants to foliar applications of auxin may help with the absorption and translocation of auxin to the site of action. Research was conducted to determine whether addition of surfactants to one-time foliar applications of indole-3-butyric acid (IBA) would be as effective as the current industry standard, the basal quick dip. Terminal cuttings of common camellia (Camellia japonica) and Teddy Bear® magnolia (Magnolia grandiflora ‘Southern Charm’) were sprayed to the drip point using Hortus IBA Water Soluble Salts™ at concentrations of 0, 500, 1,000, or 1,500 ppm or dipped for 1-sec in a solution of either 4,000 or 2,500 ppm for camellia or magnolia, respectively. A foliar application of 1,500 ppm after sticking was as effective as the basal quick-dip for cuttings of Teddy Bear®, while other spray treatments were less effective. A basal quick-dip was more effective than a foliar spray for rooting cuttings of camellia.

Keywords: Adventitious rooting, indole-3-butyric acid (IBA), surfactant

Growth of Liverwort (Marchantia polymorpha) and Spotted Spurge (Euphorbia maculata) Decreases with Substrate Stratification and Strategic Fertilizer Placement

Author: Yuvraj Khamarea, S. Christopher Marble, James E Altland, and Annette Chandler

Substrate stratification is a method of filling nursery containers with “layers” of substrates (e.g., pine bark) comprised of different physical properties to manipulate soil moisture dynamics, improve irrigation and fertilization efficiency. However, stratification could also potentially serve as a weed management tool. The objective of this research was to assess the effect of stratified substrates and strategic fertilizer placement on the germination and growth of spotted spurge (Euphorbia maculata) and liverwort (Marchantia polymorpha) establishment in nursery pots. Before experiment initiation, aged pine bark was screened to three different sizes that consisted of particles ranging from 0.3 to 0.6 cm, 0.6 to 1.3 cm, and 1.3 to 1.9 cm. Bark was also screened to pass through a 1.3 cm and included all fines (all particle sizes less than 1.3 cm). The stratified treatments consisted of either the 0.3 to 0.6 cm, 0.6 to 1.3 cm, or 1.3 to 1.9 cm applied at depths of either 5 or 7.5 on top of the < 1.3 cm substrate. An industry-standard treatment was also included in which the substrate was not stratified but consisted of only the < 1.3 cm bark used throughout the container. A controlled-release fertilizer (CRF) was used at same rate (35 g per pot) in all the treatments; However, fertilizer was incorporated in only the bottom layer in all stratified treatments (no fertilizer in the top 5 or 7.5 cm of the container media) while the industry standard had fertilizer incorporated throughout. Results showed that in comparison with the industry (non-stratified) standard, substrate stratification decreased spotted spurge germination by 30% to 84%. Spotted spurge shoot dry weight was reduced by 45% to 55% in stratified treatments when the top layer was applied at a depth of 7.5 cm, while a decrease of 14% to 42% was observed when the top layer was applied at a depth of 5 cm. Liverwort coverage was substantially reduced by nearly 100% in all the stratified substrate treatments. Overall, results suggest substrate stratification could be implemented in container production as part of an integrated weed management strategy.

Keywords: Container media, resource efficiency, weed control, weed management

Exploring Water Movement Through Stratified Substrates

Author: Kristopher S. Criscione, Jeb S. Fields, James S. Owen Jr.

An increase in horticultural production requires a greater demand for more water use. Soilless substrates, particularly bark-based systems used in nursery production, can be inefficient with regards to resource utilization. Substrate stratification is an innovative substrate management technique that involves the layering or stacking two substrates of unique hydraulics properties within the container system. The objective of this study was to monitor how stratifying substrates influences substrate water potential between two different irrigation schedules. Stratified substrates allow for added water retention in the upper half of the container, whereas in the lower half, air-filled porosity was increased. Moreover, stratified substrates significantly reduced tension fluctuations that notoriously occur in the upper portion of the substrate profile. Oscillations were even further reduced when a cyclic irrigation schedule was implemented. Thus, stratified substrates have potential for improving water efficiency in nursery crop production.

Keywords: Container media, container water dynamics, irrigation, water efficiency

Rooting Response of Piedmont Azalea (Rhododendron canescens) Softwood, Single-Node Cuttings to a Basal Auxin Quick-Dip.

Author: Jenny B. Ryals, Patricia R. Knight, Christine E. H. Coker, Gary R. Bachman, Jim M. DelPrince, Patricia R. Drackett, Scott Langlois, David Brand and Anthony T. Bowden

Piedmont azalea (Rhododendron canescens) is a deciduous azalea native to the southeastern United States as well as areas in Maryland and Pennsylvania. Cutting propagation reduces the variability observed when propagating from seed. As a whole, deciduous azaleas are known to be difficult to root via cuttings, however, piedmont azalea has been reported as moderate to easy to propagate from softwood cuttings. Piedmont azalea has been observed to root as softwood cuttings treated with a range of indole-3-butyric acid (IBA) quick dips from 5,000 to 10,000 ppm. The objective of this research was to determine rooting response of softwood, single-node cuttings to a basal auxin quick dip in order to provide growers with relevant cutting propagation recommendations. Naturally occurring auxins are produced in newly forming tissues. Therefore, a low dose of endogenous auxin might encourage young plants to root faster and more efficiently than older cuttings. Our results indicate that softwood, single-node Piedmont azalea cuttings will root with or without the use of an auxin basal quick dip. 

Keywords: Hortus IBA Water Soluble SaltsTM, IBA, propagation

Using Poinsettia and Pepper as Model Plants to Investigate Biochar and Trichoderma Suppressing Effects on Plant Diseases

Author: Ping Yu, Kevin Ong, Kevin Crosby, Terry Gentry, Mengmeng Gu

Biochar (BC) is a carbon-rich by-product from biomass pyrolysis (thermochemical biomass decomposition under an oxygen-depleted or oxygen-limited environment with specific time and temperature conditions). Biochar is of commercial importance for replacing more costly peat moss-based substrate for greenhouse plant production - and its potential to suppress plant diseases such as Phytophthora capsici and Pythium aphanidermatum. The application of Trichoderma did not significantly reduce disease severity. However, hardwood biochar (HB) mixed at 20% by volume could replace peat moss-based substrate to reduce poinsettia root rot disease caused by P. aphanidermatum without negatively affecting poinsettia plant growth. Incorporating HB by replacing 30% and 50% peat moss in the substrate could also reduce pepper blight disease caused by P. capsici.

Keywords: Disease control, hardwood biochar, Phytophthora capsica, Pythium aphanidermatum

Identification of New Crapemyrtle Bark Scale (Acanthococcus lagerstroemiae) Hosts (Spiraea and Callicarpa) through DNA Barcoding

Author: Runshi Xie, Bin Wu, Mengmeng Gu, Stacey R. Jones, James Robbins Hongmin Qin

Global trade and international travel have led to the establishment of invasive pests in territories outside the pests' normal range. We have been following the distribution of crapemyrtle bark scale [(CMBS) Acanthococcus lagerstroemiae], an invasive insect first discovered in the United States in 2004. In addition to the rapid geographical expansion of the CMBS distribution, one crucial concern is its ability to infest a wide range of plant species, beyond its primary host - Lagerstroemia. Studying the molecular evidence helps determine the genetic relationships of CMBS specimens from different geographical locations and hosts. Naturally occurring CMBS infestations were confirmed on native plant species, American beautyberry (Callicarpa americana L.), and Spirea (Spiraea L.) in the United States. The new infestation of CMBS found on Spiraea raises the alarm for the green industry that other economically important crops in the Rosaceae family might potentially be susceptible to CMBS attacks.

Keywords: Scale insect, crapemyrtle bark scale (CMBS), host range, phylogeny, species identification

Is Your Fertility Program Stuck in the 1950’s? Well, it Should be: A Nutritional Approach to Passive Plant Pest Immunity

Author: Michael Roe

Many green industry production systems are not sustainable and inherently wrong. Changes are needed in our nutritional and chemical programs that enhance sustainability: environmentally, economically, and culturally. It is possible to manage plant nutrition in such a way that plants become more resistant to insects and diseases. The plant health pyramid from Advancing Eco Agriculture® illustrates what we are trying to achieve in terms of plant growth and health. Mineral nutrition and microbiology are the foundation of plant immunity and pest resistance. Base Saturation or “ideal ratios of cations” in the soil/ container media are critical for balanced plant nutrition, health and pest resistance. Testing the leaf Brix index of plant sap with a refractometer is a quick way to determine plant health. The leaf Brix level/insect relation chart is an excellent tool for gaging plant health and pest resistance. A low leaf Brix level (0-6) indicates plant susceptibility, whereas plants are largely resistant to insects and disease at Brix levels 12 to 14. Optimizing the plant nutrient levels and minimizing pesticide usage - can significantly increase photosynthesis, Brix levels – and increase pest resistance.

Keywords: Brix, disease and pest resistance, fertilizer systems, integrated pest management, microbiology, mineral nutrition, plant health, point of deliquescence, reducing plant stress

Camellia Propagation From Cuttings

Author: Robert Black

This paper describes the protocol for production of camellias from rooted cuttings. Camellia japonica,
C. sasanqua, and C. hybrida are propagated by semi-hardwood cuttings. Cuttings are fully submerged in a
114 L (30-gal) tank of Jet-Ag® Solution (hydrogen peroxide, and peroxyacetic acid) to prevent diseases such as Pythiumand Phytophthora. The semi-hardwood cuttings are trimmed to three or four leaves, approximately 15 cm (6-in.) in length, with green mottled tan or solid tan stems. The lower leaf is removed leaving a node about 2.5 cm (1-in.) from the base. No wounding is necessary. Bundles of cuttings are basal quick-dipped for 5-sec with 8,000 ppm IBA solution using Hortus IBA Water Soluble Salts® (20%). Misting is controlled with a Phytotronics® VPD clock to maintain well-hydrated unrooted cuttings. The misting system is composed of Tavlit® 866 mini-compact sprinklers. Mist applications are significantly reduced upon root initiation. Four weeks after root initiation, both C. sasanqua and C. japonica cultivars will have rooted, and misting is discontinued. Camellia japonica cultivars require six to eight weeks to initiate rooting.

Keywords: Camellia production, Camellia japonica, Camellia sasanqua, disbudding, herbicides, Hortus IBA Water Soluble Salts®, semi-hardwood cuttings, Jet-Ag®, propagation systems, production systems, pruning, vapor pressure deficit (VPD) controller, weed management

Cutting Propagation of Magnolia Grandiflora

Author: John Davy

In Northwest Florida (Zone 8B), propagation of Magnolia grandiflora with semi-hardwood cuttings is done from 15 August to 30 November (first frost), depending on the cultivar. Soil mix and flats are drenched with the fungicide, Subdue®, before sticking. Cuttings are 10-15 cm (4-6 in.) in length, with bottom 1-2 leaves removed. Cuttings are scored 2.5 cm (1-in.) on one side, then quick-dipped for 30-sec in 10,000 ppm indolebutyric acid with potassium salt (K-IBA). ‘Brackens Brown Beauty’ is also treated with 500 ppm naphthaleneacetic acid (NAA). Avoiding over-watering cuttings is critical. Foliar application of Peters® N-P-K is applied to cuttings at low rates after callus develops. After adventitious roots appear, cuttings are drenched with the fungicide, Safari®. Rooting success rates of cultivars are as follows: ‘Claudia Wannamaker’ 95-100%, ‘DD Blanchard’ 95-100%, ‘Kay Parris’ 80-95%, ‘Bracken’s Brown Beauty’ 70-85%, ‘Little Gem’ 60-95%, ‘Opal Beach’80-90%, and ‘Seagrove’ 80-95%.

Keywords: Indolebutyric acid (IBA), naphthaleneacetic acid (NAA), semi-hardwood cuttings, Southern Magnolia.

The Does and Don’ts of Using Biologicals

Author: Chris Hayes

Nursery producers can use biologicals in integrated pest management (IPM) or Integrated Plant Health Management (IPHM) programs as stand-alone methods, or to complement chemical products for protecting plants from disease, insects, mites, nematodes, weeds – and other pests. Biologicals for plant pest control are derived from microorganisms, plant extracts, beneficial insects and organic matter. This paper describes how to properly use biologicals in IPM systems for green industry crops.

Keywords: IPM, integrated pest management, IPHM, integrated plant health management, Trichoderma harzianum

Thirty-Five Years of Propagation in 30 Minutes: Tricks and Tips

Author: Maarten van der Giessen

Van der Giessen Nursery is a 20-ha (50-ac) wholesale liner and container growing operation with a wide pallet of woody ornamental plants. We produce over two million liners a year. Our timeline for propagation begins in January and ends in December. We have five keys to successful propagation: 1. use juvenile stock -if limited to field grown material, it is best to coppice the material and take the resulting flush; 2. proper nutrition and healthy stock are critical - a nutritionally-stressed cutting will never make a good liner; 3. know what growth stage is best to maximize rooting success: softwood, semi-hardwood, or hardwood cuttings; 4. know the optimal window of opportunity to take successful cuttings; and 5. if you have correctly managed 1-4, then optimize use of rooting hormones. Recommendations are given on propagation of select species.

Keywords: Liner production, Semmes, Alabama nursery industry, propagation media, Phytotronics 1626 Clock® mist controller, side-veneer graft, softwood, semi-hardwood and hardwood cuttings, potassium salt-Indole-butyric acid (K-IBA)

Connecting Veterans to Horticulture

Author: Robert Elliott and Lis Meyer

Agriculture, the green industry and horticulture can help returning veterans integrate back into civilian life with productive careers. Likewise, the human talent and skill-sets that veterans offer can be a great employee resource for the green industry. After 15-years of service, veteran Robert Elliott returned to his family farm and developed a profitable small farming operation. Suicide is the second leading cause of death in the US military. His success (“Farming saved my life”) – the story of a veteran finding peace and a life worth living with real purpose - brought a flood of veterans to Robert’s doorstep to learn how to become farmers. Robert began working with veterans across the country and developing programs for those interested in agriculture. He also continued with his own education, pursuing a B.S. in Biological and Agricultural Engineering with a minor in Horticultural Science at North Carolina State University (NCSU). Lis Meyer of NCSU not only introduced him to the possibilities of plant propagation as a science, but also career opportunities in the nursery industry. One of the initial programs Robert started in his efforts to connect veterans with agriculture, which first involved Lis - was the Soldier to Agriculture Program (STAG) at NCSU. Robert went on to also start the Vetearns Farm of North Carolina (VFNC), which provides consultation and training to veterans and transitioning military on agricultural production methods of all scales and sizes. Its newest program is a six-month, hands-on farm training program known as the Veterans Agricultural Training and Education Program (VATEP).

Keywords: Career Skills Program (CSP), Soldier to Agriculture Program (STAG), Transition Assistance Program (TAPS), leadership, nursery industry profession, superior problem-solving skills, work ethic, Veteran’s Farm of North Carolina, Inc. (VFNC), Veterans Agricultural Training and Education Program (VATEP)

IPPS European Exchange 2019

Author: Shea A. Keene

In 2019, I was selected by the IPPS-Southern Region for their Early-Career Professional International Exchange Program to attend the European Region’s annual meeting in Stratford-upon-Avon, England. It was an awesome professional and personal experience – and my first trip abroad, alone! The exchange program was one of the best, most amazing and impactful experiences of my entire life. It was truly a priceless, once-in-a-lifetime experience that I will treasure forever - and it was only possible because of IPPS. It was my first trip abroad, alone. My gracious host was, IPPS International Chair, Tim Lawrance-Owen. I describe a number of fascinating commercial production nurseries and gardens visited, the IPPS-European Conference, some interesting historical sites and a horseback ride through Hyde Park on the final day of the exchange program.

Keywords:IPPS-Southern Region, Early-Career Professional International Exchange Program, English nurseries and gardens, Royal Horticultural Society (RHS) Garden at Wisley, IPPS-European Region Conference

Weed Control in Propagation: Hand Weeding is NOT the Only Option

Author: Anthony Witcher and Isha Poudel

Weed control in nursery crop propagation is difficult due to the limited methods that are safe and effective. Hand weeding is labor intensive and time consuming and the availability of agriculture labor has become limited in recent years. Adoption of sanitation practices helps minimize weed infestations, but utilization of pre-emergent herbicides and mulches may be a viable weed control method in propagation. Although certain pre-emergent herbicides may cause injury to seedlings and rooting cuttings, there are non-root-inhibiting herbicides that may be safe for use in propagation. Three studies were conducted evaluating pre-emergent herbicides and mulches in seedling and stem-cutting propagation in small diameter containers. For seedling propagation, we found that isoxaben (Gallery) was safe when applied to small seedlings of several tree species after transplant and several pre-emergent herbicides were safe when applied prior to germination of oak seeds. For stem cutting propagation, oxadiazon+oxyfluorfen (Regal O-O) provided broad spectrum weed control and was safe when applied 2 weeks after sticking cuttings of several crop species. Pine pellet mulch provided excellent weed control at 1-cm (0.5-in.) depth with no impact to cutting root development.

Keywords: mulch, pre-emergent herbicide, seedlings, stem cuttings

Ornamental Winners and Losers in the Record Texas Freeze of February 2021

Author: David Creech, Lais Machado and David Kulhavy

There was a record 100-year freeze in Texas from 15-21 February 2021. Temperatures dropped as low as -20oC (-4oF). For landscape plants, going from Zone 8b to a 5 was a bit much. Besides the low temperatures, the heavy ice and snow load further stressed plants in the Pineywoods of East Texas. We are developing a tome that describes the immediate and long-term impact of winter storm Uri on the Texas landscape. Recording a list of plants that thrived, survived or died would be useful to future landscape planners. While the tolerance of common plants was evaluated, the focus was on rarely encountered ornamentals. Stephen F. Austin Gardens (SFA) Gardens is a perfect platform to deliver freeze data - because it is a collector’s garden of exotic plants. Hundreds of new plants are added to the landscape each year, which is a perfect crucible to test a wide variety of ornamentals exposed to extreme temperatures. The focus of this paper is limited to a few select genera, particularly those with adequate numbers for evaluation at SFA Gardens.

Keywords: hundred-year freeze, tome, low-temperature - woody ornamental plant stress tolerance, plant evaluations