Fig. 1. Caterpillars feeding on the underside of leaf
Photo: Raymond Cloyd, KSU
Microbial pesticides, which are a class of biopesticides, consist of microorganisms such as bacteria, fungi, viruses and protozoans. The most widely used microbial pesticides are those derived from Bacillus thuringiensis (Bt), which is a naturally occurring soil bacterium. Individual strains of the bacterium produce a different mix of proteins that specifically kill one or a few related species of insect larvae. The most commonly used microbial pesticide is Bacillus thuringienesis subsp. kurstaki (Btk), which is only active on caterpillars that feed on greenhouse-grown vegetable crops (Figs. 1 and 2). A common product used in greenhouse vegetable production systems is Dipel (Fig. 3).
Bacteria, unlike fungi, must be ingested to be active. Therefore, thorough coverage of all plant parts, especially the upper and lower side of leaves on which caterpillars feed, is important so that residues of the bacterial spores can be ingested during feeding. Once consumed, the bacteria produce an endotoxin or crystalline protein that dissolves in the alkaline content (>7 pH) of the caterpillar stomach. The crystals then bind to the lining of the gut membrane, dissolve the stomach lining and create pores that result in leakage and swelling. The swelling continues until cells burst, which allows the highly alkaline gut contents to enter into the insect’s body cavity and bloodstream (hemolymph). This disrupts the blood, resulting in paralysis and death within 24 to 72 hours.
Fig. 2. Caterpillar feeding on the underside of lettuce leaf
Photo: Raymond Cloyd, KSU
Btk must be applied when caterpillars are present, and young and small. When caterpillars are small, they do not have to consume as much plant material for the bacteria to be effective. Caterpillars must also be killed before they cause substantial plant damage and prior to reaching the reproductive phase (adulthood) of development. If Btk is applied later in the growing season when caterpillars are larger, it is too late because the caterpillars have to ingest much more plant material containing the bacteria to be effective. Furthermore, caterpillars may transition from the growing phase to the reproductive phase before consuming enough of the bacteria, which results in a higher probability of adult survival, leading to new generations of adults that will be produced in the future.
Btk has very short residual activity due to breakdown when exposed to sunlight (ultraviolet degradation). In addition, the wavelength of light transmitted may influence residual activity. For example, wavelengths greater than or equal to 400 nm can significantly reduce the viability (ability to survive and live) of Btk spores. Therefore, frequent applications and applications made in the evening are warranted in order to maintain residues of Btk spores on leaf surfaces. In addition, Btk is slower-acting than most conventional insecticides and must be applied before caterpillar populations reach damaging levels. Due to the selectivity of Btk, there is minimal potential direct harm to natural enemies including parasitoids and predators. However, Btk will kill host caterpillars, which can indirectly affect natural enemy populations.
Fig. 3. Product (Dipel) containing Bacillus thuringiensis subsp. kurstaki as the active ingredient
Photo: Raymond Cloyd, KSU
The mode of action of Btk is specific to caterpillars, so there are no harmful effects to mammals. Btk must be stored under temperatures between 50 and 60° F to prolong shelf-life. Exposure to cold (<32° F) and hot (>90° F) temperatures will reduce the viability of the bacteria. Water quality may also negatively influence the viability of the bacteria. For instance, alkaline water, with a pH >8, will reduce the effectiveness of the toxin associated with Btk. The appropriate water pH should be =7.
Fig. 4. Diamondback moth larva
Photo: Raymond Cloyd, KSU
It is important to not solely rely on Btk to suppress caterpillar populations because, like most insect and mite pests, using the same mode of action continuously can result in resistance. For instance, both the cabbage looper, Trichoplusia ni, and the diamondback moth, Plutella xylostella (Fig. 4) can develop resistance to Btk. Therefore, be sure to rotate Btk with other insecticides registered for use against caterpillars to mitigate any issues associated with resistance. In greenhouse vegetable production systems, applying Btk in conjunction with early releases of certain species of the parasitoid Trichogramma ssp. may be an effective strategy of maintaining specific caterpillar pest populations below damaging levels.
Raymond is a professor and extension specialist in horticultural entomology/plant protection in the Department of Entomology at Kansas State University. His research and extension program involves plant protection in greenhouses, nurseries, landscapes, conservatories and vegetables and fruits. rcloyd@ksu.edu or 785-532-4750
When I was in Auckland, New Zealand late last year, I was amazed at how much greenery there was throughout the city. We spent a couple of days meandering between towering skyscrapers and historic city parks with giant trees, exploring beautiful urban cemeteries and university gardens, and strolling along flower-lined walking paths and through busy commercial zones.
I suppose I shouldn’t have been surprised to come across community gardens bursting with fresh veggies, seeing as a large portion of the rest of the country is dedicated to agriculture, but somehow, I’m still not used to seeing produce growing in what probably was once a parking lot between two buildings. But those tomatoes, peppers and bee hives were a welcome sight, and we stopped to take a look.
More and more cities are taking note of the fact that incorporating plants and gardens into cityscapes is beneficial both for the residents’ mental and physical wellbeing. This month’s Urban Agriculture series article is about these community gardens and plants, and how growers can be more involved. Read it here.
Going further, finding ways to produce more locally grown food on a commercial scale is of increasing interest to cities like Atlanta, featured in this month’s cover story. The city hosted its second annual AgLanta conference this past March, with a focus on boosting urban agriculture and improving the city’s connection to its food, eliminating food deserts along the way. In addition to AgLanta, Atlanta is working with 100 Resilient Cities, an organization that aims to strengthen the cities it works with. To read more about how Atlanta is striving to become a hub for urban agriculture, click here.
At the 2018 AgLanta Conference in late March, growers, tech professionals, business owners, venture capitalists and government officials convened at the Georgia Freight Depot in Atlanta with one overarching topic in mind: urban agriculture.
The second annual event featured panels covering topics from smart resource management to the value of urban agriculture to what consumers want from food in a digital age. Attendees came to Atlanta with varying levels of experience — some were still in college, still looking for their first break; others were seasoned professionals who owned or worked for thriving businesses — but everyone was there to learn.
But the AgLanta Conference also was, and will be in years to come, part of Atlanta’s investment in urban agriculture. Since 2015, Georgia’s largest city — population 472,522, according to the most recent U.S. census — and state capital has been working to improve and stay attuned to the needs of its citizens. An essential part of those efforts is urban agriculture and making fresh, healthy food more readily available to the people of Atlanta. In addition, they're working toward improved housing, civic unity and an overall stronger city.
“These are chronic stresses,” Otis Rolley, the managing director for 100 Resilient Cities, says. “So we need to build them up on both an individual level and a structural level of our cities to think about what you have to do, and how you can invest, to make cities more resilient and deal with the shocks and stresses.”
An exercise in resilience
100 Resilient Cities, an extension of the Rockefeller Foundation, is an organization that aims to do exactly what its name implies: make cities stronger. It helps cities all over the world adapt and react to the “physical, social and economic challenges of the 21st century,” according to its website. Cities such as Accra, Ghana; Athens, Greece; and Singapore are among the non-North American cities involved with the organization. In the United States, Atlanta is one of 22 cities — including New York City, San Francisco and Dallas — working with 100 Resilient Cities. San Juan, Puerto Rico, is also a resilient city, as are Calgary, Montreal, Toronto and Vancouver in Canada.
In each city, 100 Resilient Cities implements a plan custom-fit for its needs, although there are some core principles to each resiliency plan. To start, a Chief Resiliency Offer is appointed — in Atlanta, Stephanie Stuckey originally held the role and Cicely Garrett is the current Interim Chief Resilience Officer — and 100 Resilient Cities covers the officer’s salary for the first two years. Additionally, an overall resiliency plan is developed between city leaders and 100 Resilient Cities. Member cities also consult with other cities about what worked in different locales, and seek partners in private, public and NGO sectors to help each city implement its plan. More than 7,000 Atlanta residents were engaged during the city’s resiliency planning phase.
“We try to help people and help them understand how the world operates,” Rolley says.
In Atlanta, one of the main concerns the resiliency plan aimed to address was access to fresh, local food. According to Stan Vangilder, program manager at the Southern Company, an energy company in Georgia, 25 percent of people living in the Atlanta metropolitan area live more than half a mile to the grocery store and do not have access to a car; this is more commonly known as a food desert. Also, Vangilder says one in four Atlanta families with children are considered food-insecure, which the USDA defines as a situation when “consistent access to adequate food is limited by a lack of money and other resources at times during the year.”
Otis Rolley (left) and Mario Cambardella (right)
Photo courtesy of Agritecture
In short: Many Atlanta residents are simply not in a position to be able to buy and eat the kind of food they need to sustain a healthy diet.
“Any movement towards more plants can improve your health,” Vangilder says. “Diets for [people in food-insecure communities] tend to be high in processed, high-calorie and low-nutrient foods. That is not good stuff. Food security and health are inextricably linked.”
A central part of Atlanta’s resiliency plan is making fresh food available within one half-mile of 75 percent of its residents by 2020 and increasing that to 100 percent of citizens by 2025. At AgLanta, Rolley called this a “non-negotiable” benchmark for the city. Vangilder also notes that work needs to be done to prove to people that locally grown, healthy food doesn’t have to be expensive and only for higher-paid citizens.
He also said that to help black Atlanta residents — who make up 54 percent of the city’s population, according to the most recent census — improving business opportunities and access to healthier food are key parts of the plan. According to the 2010 census, Atlanta is the fourth-largest black-majority city in the U.S., and Rolley says data shows that they are at a disadvantage.
“There is a huge disparity between African-American wealth and white wealth,” he says. “If a city is really serious about being a global city, then we have to deal with, in a substantial way, around creating more economic activity particularly for African-American Atlantans.”
Events like the AgLanta conference aim to engage the community with agriculture.
Photo courtesy of Agritecture
Making progress
In an effort to meet its goals, Atlanta hired Mario Cambardella as the city’s urban agriculture director. He is the first person in the United States to hold that role in a major city.
Cambardella is a graduate of the University of Georgia, where he earned his master’s degree in environmental planning and design. He calls his job of developing Atlanta’s urban spaces a “dream job.” Agriculture is part of his family history as well. His grandparents emigrated from a small farming community in Naples, Italy to Brooklyn, New York, in the 1930s, and helped build community gardens there.
Cambardella’s day-to-day tasks can range from helping an Atlanta resident place a water meter at a community garden to issuing a permit.
“My job is to empower constituents,” he says.
Overall, Atlanta’s agricultural efforts are centered on helping residents better their lives. AgLanta.org serves as the digital component of the efforts. There, residents can find digital resources about local food and different events the city is holding to engage the community and help them better understand food. One such event is the AgLanta Eats food festival, which took place in July and raised money for AgLanta's Grows-A-Lot program.
The Grows-A-Lot program is at the core of what Cambardella and the rest of the city strive to improve. Organized by Groundwork Atlanta, a local branch of the Groundwork USA network that works with the environment, equity and civic engagement and the office of resilience, Grows-A-Lot gets urban farming space to citizens who can utilize it. In the program, vacant property owned by the city and Georgia Power is made available to urban farmers and community gardeners who want to put the property to good use. Lots are available to parties interested and can be rented with five-year leases, with an option to renew for three more years after that.
“We want to enable all Atlantans to prosper,” Rolley says. “We also realize that we cannot push forward a resilient Atlanta without the citizens of Atlanta.”
Other AgLanta initiatives include the AgLanta Academy, a public workshop series that allows citizens to learn about urban ag and helps attendees establish connections with various local businesses that can help train citizens in urban agriculture. There is also an urban food forest in southeast Atlanta that produces fresh food in what was identified as a food desert.
The Grows-A-Lot program puts urban farming space into the hands of Atlanta residents.
Photo courtesy of AgLanta
The next steps in Atlanta’s plan
Georgia's state-wide agriculture industry is a key part of plans for future growth. At the AgLanta Conference, Gary Black, the commissioner of the Georgia Department of Agriculture, said that he saw Atlanta’s developing urban agriculture as a key part of the future of the state’s argricultural business and the #GeorgiaGrown initiative the state is working on to better market produce grown in the Peach State.
Additionally, there is a massive market for locally grown food. According to Vangilder, the Southern Company estimates that there is a $780 million market for new growers and a $300 million market for existing growers in Georgia alone. Vangilder says that Georgians are only producing one-tenth of the lettuce they eat in a given year. This means that there is not only a need for produce local consumers can readily purchase, but also the need for new businesses to form and entrepreneurs to lead those businesses in their neighborhoods.
“We don’t eat what we grow,” Vangilder says. “But what if we did? That could improve community health.”
This is where Atlanta’s plans come to a head. Two years into the collaboration, the city is launching plans that engage citizens and propel it towards its goal. As it moves into its next stage, and leaders like Cambardella and Rolley help to shape the next phase of the plan, the idea is to keep making the plan work for the people of Atlanta by tweaking what's necessary and keeping what’s working going.
“We are building a network,” Cambardella says. “It’s about food, but it’s not about food.”
Cultivating community
Departments - Urban Agriculture
Growers and retailers connect with the community and school garden movement.
Fig. 1. Community gardeners grow a variety of plants, including food and ornamentals. The garden shown here, in Orono, Maine, is an educational community garden with a variety of ornamental beds. However, the community members also grow vegetables that are donated to local food pantries.
Photo: Katherine Garland and Stephanie Burnett
People throughout the nation are eager to grow food to feed themselves and their neighbors. Community gardens are popping up like wildfire to meet the needs of the many home growers who have limited access to quality soil, full sunlight, water and overall space. Many of these gardens are great spaces for those who simply want to garden in the company of others. The American Community Gardening Association estimates there are approximately 18,000 community gardens in the U.S. and Canada. These gardens come in a wide range of organizational formats including, but not limited to: spaces dedicated for certain neighborhoods, leased plots, school gardens, service (food security) gardens, vocational training gardens and guerrilla gardens (Figs. 1 and 2). Community gardens are very fun and exciting, but they often require a surprising amount of time and energy to thrive and become an integral part of the community over the long run. Commercial horticultural enterprises of all sizes can take some simple steps that can play a big role in helping new and existing community gardening initiatives become and remain a successful resource for your communities. This is a wonderful way to connect with some of the most enthusiastic gardeners in your area and support your community.
One of the easiest ways to support community gardens is to tell their story on your website or social media outlets. Building awareness is tremendously helpful, especially as community gardens are just getting established. Consider a live interview on Instagram or Facebook with the community garden organizers or a simple walking tour of the site. Sharing photos of best practices being demonstrated in the community garden is always popular (ex: unique use of vertical space, succession planting, aesthetically appealing layouts, etc.). You could set a goal to profile area community gardens once a month. Be sure to tag the garden and your business to increase your audience reach and build community connections.
Many greenhouses are in a good position to donate excess seed and plant material to community garden resource hubs. Your local Cooperative Extension office is often a great resource to connect you with community gardens that may be in greatest need of these excess materials. In some cases, communities have programs set up to make the donation process quite easy. For example, the Minnesota State Horticultural Society implements a plant redistribution program called Minnesota Green where they help get the word out about donations to leaders of public gardening initiatives.
Many greenhouses can donate excess seed and plant material to community garden resource hubs.
Retail garden centers could also encourage their customers to donate materials through gift registries for community gardens (ex: hoses, watering wands, soil amendments, trellising materials, compost, etc.). Many potential community garden supporters are much more enthusiastic about donating materials than money. They like to see how their dollars are being used and like to support local businesses too. If you don’t have the capacity to do a registry, consider the Christmas is for Kids model, but instead of a Christmas tree with gift wishes for individual kids, have tags for supplies needed by specific community gardens. People can buy the materials at your store too!
Fig. 2. Sometimes, community gardens do not have ideal soil because of their urban settings. However, raised beds and dedication allow these gardens to thrive in sites that would otherwise be barren.
Photo: Katherine Garland
Your employees may also enjoy working in community gardens, and they have knowledge and talent to share with new gardeners (Fig. 3). Some operations, such as Bell Nursery in Baltimore, set aside employee work days for volunteering at a community or school garden. In 2015, their initial community garden project involved building five large raised beds in a vacant city lot shortly after the Baltimore riots. “The following year, we expanded to a second location to assist a community leader that was renovating and reviving a center for youth,” says Susan Summers of Bell Nursery. “Four more raised vegetable gardens and flower beds were planted and now both communities are harvesting hundreds of pounds of vegetables every summer! These areas are all considered ‘food deserts’ as well.” They plan to add a third garden this year at an adult transitioning home.
If you are interested in donating produce to local food pantries, you and your employees could sponsor a plot in a local community garden in which the food is donated to the hungry (Fig. 4). One company in Maine, IDEXX, has expanded on this idea by creating a company-sponsored community garden where employees have paid time to work in raised beds at their corporate offices and food grown is donated to food security agencies. “It’s really strengthened them as employees and work teams . . . a win-win for the business and the people who need the food,” says Amy Witt, UMaine Cooperative Extension horticulturist who helped them get established.
Fig. 3. You can give your employees release time to work on the board of community gardens. Their expertise will help these gardens thrive.
Photo: Stephanie Burnett
Another approach to enhancing food security efforts is to serve as a drop-off site for produce donation for hunger relief organizations. Many community gardeners are interested in donating excess produce from their gardens, but aren’t available to drop it off at food pantries during the specific hours they’re open. Normal retail business hours leave a wider window of opportunity for donors to connect their excess food with neighbors in need. Simply have a good place to temporarily store donated food and make arrangements with a food security agency to stop by to pick up donations on a regular basis.
Horticultural employees might want to serve on a community garden board of directors to provide technical support. This support helps to develop the literal and figurative foundation of the garden. The Yarmouth, Maine, community garden has benefited from the support of a board member from the green industry. Retail professionals in particular often have good insight about how to assess the needs of the community because they might hear of community garden inquiries from their customer base.
Fig. 4. Community gardens, such as the one pictured here, can be sponsored at your greenhouse for employees.
Photo: Lisa Steele
If you own a retail garden center, you can offer a wide variety of services for community gardens. Your greenhouse can serve as a meeting space in winter for planning meetings. People can also sign up for information about community gardens at a central location. Simply having a small resource space can help your customers connect with opportunities that will help them grow and get involved in their community. Some retail operations have roundup days for community gardens. If customers are interested, they can round up their total purchase amount to the nearest $5 increment to donate to a community or school garden project. You can also offer discounts to certified community garden volunteers and educators. Discounts, no matter how large or small, can serve as a great incentive and thank you to those who make community gardens happen. Volunteers are the backbone of community gardens. Make sure they stick around and feel appreciated! Finally, if you host public events, you might consider offering an event where the suggested donations go to a gardening non-profit. This is a great opportunity to bring in new customers, and it also raises awareness about area service agencies.
Acknowledgements. Financial support was received from the USDA National Institute of Food and Agriculture, Multistate Research Project NE-1335: Resource Management in Commercial Greenhouse Production. Katherine is a horticultural professional with the University of Maine Cooperative Extension (katherine.garland@maine.edu) and Stephanie is an associate professor of horticulture with the University of Maine (sburnett@maine.edu).
Be a mentor
Departments - Edible Insights
Serving as a mentor to another employee or industry member can be invigorating.
When you’re young, or transitioning to a new field, treading unfamiliar professional waters can be daunting. You don’t have enough experience to really know what you’re doing, and without guidance it’s easy to make a lot of crucial mistakes. When you’re established in your career it’s easy to get in a rut and find yourself impatient with new perspectives and methods. In both cases, getting out of your own head is advisable. How do you do that? Find a mentor. Better yet, be a mentor.
Pay it forward
If you were lucky enough to benefit from someone mentoring you, it might be time to pay it forward. Being a mentor is sort of like teaching a new topic. When you must teach something, you tend to learn a lot more about it at the same time. So, if you’re finding yourself in a rut, or could use some fresh perspective and inspiration, being a mentor to another employee or industry member can be invigorating. The first signal that you may need to step up to a mentorship role is when you start getting unsolicited inquiries from younger employees or career-transitioners for advice.
I recently interviewed several people in the green industry for their thoughts on industry relationships and networking, asking them, “Do you actively mentor within the green industry?” — all were eager to offer up that mentorship was something they valued and engaged in frequently.
Dr. Bridget Behe, Michigan State University: “Yes. Often and with as many [mentees] as I can. Talking with them about work but also life. Nurture good relationships, keep them as an important part of your life and invest in them. Prune the relationships that aren’t positive and enjoyable. I’m a big believer in the ‘7 Habits of Highly Effective People.’ I teach it and strive to live by it.”
Brie Arthur, horticulturist and green industry communicator: “Yes, I have been very fortunate to connect with students through IPPS and NCSU horticulture programs. It is very rewarding to share my past experiences, host them for garden tours and meals and help guide them through a meaningful career in horticulture. I have written many recommendation letters lately and I believe the future is bright with this new generation rising.”
Christina Salwitz, The Personal Garden Coach: “I get requests to mentor people frequently, and I am always happy to do that whenever I can. It’s often a coffee chat, email connection or meeting at an industry event. Sometimes, a person needs details about steps they might take or confirmation of decisions from a subjective source, and sometimes they want to learn what I do in my own processes. I was given an invaluable mentoring opportunity when I began, and we are still friends and valued confidants to this day. I am a firm believer that women use this ability the best because of our natural nurturing skills.”
Jill Hoffman, Hoffman Nursery: “Yes, I try to mentor women in the industry — mostly our employees and students. The biggest way to do this is by offering employees opportunities to attend conferences and tradeshows for learning and networking opportunities and offering students opportunities with internships here at the nursery. It is important to get them involved in the industry, whether it is giving them a role on a site committee for an upcoming conference or a chance to speak to others outside the nursery about what they do. It helps to share with them what is going on in the green industry and get them excited.”
Making the connection
Such informal one-on-one relationships are the most typical types of mentorships. And there are many within our industry who are proactively generous with their time. But not all of us are lucky enough to organically cross paths with someone who has the right experience and willingness to become our mentor. Many young employees may either not feel comfortable asking someone to mentor them, or not even think about it as a possibility. Older professionals often have their hands full, and actively pursuing mentorship duties can sometimes feel like an added burden.
Generation gap
I also see a lot of value in creating meaningful relationships between older and younger employees on your team. Doing so can help you bridge common communication gaps and provide invaluable new perspectives to each team member. Now, mentors don’t always have to be older than the people they are mentoring. The ability to mentor comes down to experience and what you have to offer someone building their career.
Structure and incentives
To encourage mentorship within your company, you probably need to create some formal structure and incentives. Depending on the size of your company, consider assigning all new hires the opportunity to formally connect with an assigned mentor within the company. Start by talking to existing staff to find out who wants to volunteer as a company mentor. Mentors should be experienced in the industry and have at least several years under their belt working at your company. Company mentors should aim to meet monthly with the employee they are mentoring — on company time — and of course be available for some emails or phone calls now and then. Give your mentors a small spending budget so the pair can get out of the office for a lunch meeting now and then. For employees willing to volunteer as mentors, consider offering incentives such as some extra paid time off.
Not everyone needs a mentor — or needs a mentor all the time — but just as with industry networking, making meaningful connections with other professionals often opens the door to new possibilities and opportunities.
Leslie (CPH) owns Halleck Horticultural, LLC, through which she provides horticultural consulting, business and marketing strategy, product development and branding, and content creation for green industry companies. lesliehalleck.com
