Aphids are major insect pests of greenhouse-grown horticultural crops including ornamentals and vegetables. One of the most common aphid species encountered in greenhouses is the green peach aphid, Myzus persicae (Figs. 1 & 2), which feeds on >400 plant species in 40 different plant families. Green peach aphid causes direct plant damage by withdrawing plant fluids from the phloem sieve tubes with their piercing-sucking mouthparts, resulting in leaf distortion, plant stunting and plant wilting. Indirect damage is associated with the production of honeydew (clear sticky liquid) and transmission of plant viruses during feeding. In addition, a short generation time and high female reproductive capacity allows green peach aphid populations to quickly reach damaging levels.

Insecticide resistance

Therefore, insecticides are routinely applied to suppress green peach aphid populations (Fig. 3). However, the short generation time and high female reproductive capacity of the green peach aphid also contribute to their propensity to develop resistance to insecticides. As such, the intensive use of insecticides to manage green peach aphid populations has resulted in populations that are currently resistant to a number of insecticide classes. In fact, the continual reliance on insecticides and subsequent intensive selection pressure has led to green peach aphid populations developing multiple resistance mechanisms that have enhanced resistance to most chemical classes including: organophosphate, carbamate, pyrethroid and neonicotinoid. Currently, the green peach aphid has developed resistance to >70 different compounds. Furthermore, the green peach aphid is able to overcome the toxic effects of insecticides based on six different resistance mechanisms.

These resistance mechanisms confer resistance to different chemical classes (indicated in parentheses) and are affiliated with: 1) overproduction or enhanced production of detoxification enzymes that break down the active ingredient before reaching the target site in the central nervous system (organophosphates, carbamates and pyrethroids); 2) changes or mutations in specific enzymes that decrease sensitivity to certain insecticides by modifying the target site (carbamates); 3) changes in the voltage-gated sodium channels (pyrethroids); 4) over-expression of detoxification enzymes (neonicotinoids); 5) reduced penetration through the cuticle (neonicotinoids); and 6) changes or alterations in the target receptor sites (neonicotinoids).

Table: Raymond CLoyd

Most resistance mechanisms are associated with increased or enhanced production of metabolic detoxification enzymes or modification of target receptor sites in the central nervous system, resulting in reduced sensitivity. Moreover, several resistance mechanisms may be present, thus resulting in green peach aphid populations that are resistant to multiple insecticides with different modes of action. Some of these mechanisms evolved early in response to plant chemical defenses or plant-derived toxins and have been manifested after exposure to insecticides. Furthermore, the green peach aphid is a generalist herbivore and has a greater propensity to develop resistance to insecticides due to the presence of a variety of resistance mechanisms that confer resistance to plant chemical defenses or plant-derived toxins. In fact, some insecticides have similar properties to plant-derived toxins. For instance, the pyrethroids are synthetic derivatives of pyrethrins, which are natural components of the chrysanthemum, Tanacetum cinerariifolium, flower. As such, similar resistance mechanisms can confer resistance to pyrethrins and pyrethroids.

Another type of resistance mechanism is referred to as “behavioral avoidance,” which confers resistance to neonicotinoids. Behavioral avoidance is associated with green peach aphids spending more time on untreated leaves than treated leaves. Aphids will disperse away from insecticide-treated leaves. For instance, the green peach aphid tends to avoid residing and feeding on leaves treated with imidacloprid and will move to untreated leaves. However, it should be noted that imidacloprid does have repellent activity, so “behavioral avoidance” may not solely be responsible for resistance.

Mode of action types

There are two mode of action types associated with insecticides: narrow and broad-spectrum. Narrow-spectrum (site-specific) modes of action insecticides are active on specific target sites such as the central nervous system or enzymes associated with metabolism. Broad-spectrum mode of action insecticides are active on a variety of target sites or possess multiple modes of action. For example, some of the more “selective” insecticides such as pymetrozine (Endeavor), flonicamid (Aria) and cyantraniliprole (Mainspring) may be less prone to resistance due to their broad-spectrum modes of action compared to insecticides with narrow-spectrum modes of action. In fact, pymetrozine exhibits no cross resistance (based on a single resistance mechanism conferring resistance to pesticides in the same chemical class and/or having similar modes of action) to either pyrethroid or carbamate insecticides.

The best way to mitigate resistance is to rotate insecticides with different modes of action throughout the growing season when green peach aphid populations are present. Table 1 presents a list of some insecticides that are labeled for use against aphids and their designated mode of action.

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

What’s it like growing up in your family’s greenhouse business? It’s “a lot of work,” says Griffin “Griff” Sprout, the second-generation owner of Sprouts Greenhouse in Lander, Wyoming. His parents, Charlie and Lynn, opened the business in 1978, and their children made up the primary workforce until they could afford to hire employees.

This early exposure to plants cultivated an agricultural interest in Griff, who grew FFA and 4-H projects in his own section of the greenhouse, in addition to working there after school. He wanted to pursue international agricultural economics, with the dream of working at a foreign embassy in Africa.

“I enjoyed the business growing up, but it wasn’t necessarily my plan after school,” he says. “I went to college with no intention of coming back to the business. But working during the summers and busy weekends in the spring, the business started growing on me.”

After college, in 1998, Griff committed five years to the family business. Working alongside his parents wasn’t always easy. But as the retail greenhouse continued to grow, he became more invested in its success. At the end of those five years, he decided to partner with his parents, gaining an equal share of ownership.

Then, following his mother’s death in 2006, Griff bought the rest of his father’s shares in 2010. Now as owner, Griff oversees the day-to-day activities of Sprouts Greenhouse to carry on the family tradition.

Tech tools

Charlie Sprout relied on memory to maintain production schedules. But as Sprouts’ inventory grew, Griff needed new tools to consistently manage all the plants, sales and orders. Over the years, he custom-built his own database to organize and access these details more efficiently.

“Having tremendous diversity really helps our overall sales and differentiates us from the box stores,” Griff says. “It would be a lot easier to only do five colors of pansies, but it’s more fun to do 60 colors. That’s why database management is so important for us: I can track things better.”

Griff’s custom database syncs with the company’s accounting software and point-of-sale system — which he also introduced. This gives him full visibility into critical business data, helping him predict trends and make more informed decisions as new varieties are introduced.

By Griff’s estimate, Sprouts Greenhouse grows 1,500 varieties of annuals, perennials, vegetables and herbs in 35,000 square feet of covered production space. “That’s more than you can keep track of in your mind,” he says. “It becomes very complicated very quickly, but with the right management tools, you can simplify it a lot.”

Community presence

As much as technology has helped manage the family business into the second generation, Griff says that Sprouts’ success still stems from good, old-fashioned relationships with customers and surrounding communities.

He stays involved by donating to the local food bank, churches and civic groups, hosting and speaking at events, and partnering with youth ag education programs like FFA and 4-H — the same ones that helped get him into growing.

“Every time someone comes in for a donation, I believe it’s a much more effective use of money than advertising,” Griff says. “That direct effort to help other organizations is a great opportunity to create a community presence. [That] doesn’t always come [back] directly as sales, but it benefits us in other ways.”

Community engagement, for example, has become an effective recruiting strategy for Sprouts. Through his network of local connections, Griff often encounters high school students who’d make a good fit at the greenhouse, and offers them jobs. They’ve turned out to be some of his best employees.

“A lot of people are complaining about the labor shortage, but that’s not something we struggle with,” Griff says. “If anything, we’ve done really well with employee retention. We get the same [seasonal employees] back every year.”

During peak production, Sprouts employs about 25 people, and up to 30 during heavy retail season. Griff may hire an employee initially to focus on growing, then train them to work in the store when it gets busy. Outside of key positions like head grower, “There’s always a lot of crossover,” he says. “The growing team becomes the retail team, eventually.”

Growing up green

Today, Griff’s children don’t have to work in the business like he did at their age, because he has plenty of employees. Still, he wants to offer his kids the experience he had growing up in the greenhouse, so he brings them in for “Wednesday Workday” every week. His son and daughter are quickly becoming familiar faces at Sprouts, carrying on the company’s kid-friendly tradition.

“Our business is family-oriented, and we want families to come out and bring their kids shopping,” says Griff, who invested in big, kid-friendly carts to improve the family shopping experience. “We want to create an environment that’s friendly for that.”

Most weekdays during the spring, Sprouts Greenhouse hosts educational school tours for local students, from kindergarten through high school. At the end of the tour, each student gets a small plant (usually a coleus or pansy) to take home.

“I’m very passionate about getting the next generation into growing,” Griff says. “I love to see people get excited about growing things. There’s a huge part of our business that’s a fantasy, a dream [of how a plant will turn out], and I really enjoy fostering that in people.”

Brooke is a freelance writer living in Cleveland.

Many greenhouse operations rely on irrigation systems for their watering needs. While different growers use different types of systems, the purpose of each system is the same: to water plants efficiently and effectively.

But sometimes, irrigation systems can become clogged, causing production issues and negatively impacting plant growth. The good news is that it’s a manageable problem with viable solutions that growers can implement.

“We are all very aware of the importance of watering,” says Rosa E. Raudales, an assistant professor of horticulture and a greenhouse extension specialist at the University of Connecticut. “We’re also aware of the importance of not over-watering, but also [of] not stressing our plants. If you allow your system to clog, then you’re losing control because you can’t really estimate how much you’re going to water.”

The three types of clogging

According to Raudales, there are three kinds of clogging growers should be aware of: physical, biological and chemical. She says that each type has different causes and symptoms that when identified, allow growers to zero in on the problem afflicting their greenhouses.

For physical clogging, she says it involves a suspended solid backing up the system, thus preventing water from reaching the plants.

“Think of if you’re [a grower] recirculating water and if you’re carrying any type of remaining debris that’s coming back from the soil,” she says. “You would expect a physical [object] that would plug your system. Mostly that would be a concern for growers who are recirculating water or maybe growers who are using pond water as their water source because it tends to be a little dirtier than other sources.”

Biological clogging occurs when biofilm — commonly known as lime — builds up in an irrigation system’s pipes and slows or stops water flow, Raudales says. It is most often greenish-brown colored, giving growers a visual indicator that their pipes are clogged.

“[Biofilm] is mostly foreign debris caused by bacteria, but you can also think of it as a combination of bacteria and algae,” Raudales says. She adds that biological clogging can be the hardest type of clogging because there isn’t a comprehensive solution for it.

Lastly, there is chemical clogging to treat. Raudales says that this can be caused by different materials building up in the system, most notably iron. This type of clogging, she says, is often caused when a water source such as a well is contaminated and introduces harmful materials into the system. Calcium, manganese and other materials can also precipitate clogging.

Different treatments for different types of clogs

Raudales says treating physical clogging is straightforward and researchers know the most about it — making it the easiest type of clogging for growers to deal with. Often, the material clogging the pipe is something that can be blown out the front of the system and out of the greenhouse altogether. All a grower needs to solve this issue is pressure.

For biological clogging, Raudales says it can take a “big effort” to combat it properly. For instance, if a propagation house’s emitters are clogged with biofilm, growers must choose between a few different treatment strategies. One is to take the emitters down, replace them with clean ones and wash the clogged ones. Chemical treatments are also an option, although bacteria can become resistant to them over time.

As for chemical clogging, the process is like treating physical clogging. Raudales says that it requires using a large concentration of the chemical being used to clear out the pipe and the line being shut down. It also requires an empty greenhouse, or temporarily emptying a greenhouse, to avoid damaging plants.

The best way to combat clogging, Raudales says, is to be aware of the different symptoms of clogging.

The one significant factor that Raudales says links the different treatment options together is that unclogging irrigation systems is a labor-intensive process, and not all growers can take workers off other tasks in the greenhouse and assign them to the problem.

“If we don’t find a way where you can install a system that helps you treat the symptoms, treat the water as it goes and prevent the problem from happening in the end, then this is just going to happen,” Raudales says. “If they don’t have the alternative to do that, then it becomes something that’s very labor intensive. But they don’t have many alternatives other than [to] treat it or [to] spend the time cleaning. It's one or the other.”

Best practices to combat clogging

The best way to combat clogging, Raudales says, is to be aware of the different symptoms of clogging. Mum growers watering their plants with drip irrigation, for instance, should look for wilted plants and check them on a schedule. If a grower notices the wilting early enough and can fix the clogging issue promptly, then it might be early enough to fully salvage the crop.

There are also specific signs of the various types of clogging, Raudales says. For chemical clogging, growers can likely spot some residue in the piping before it is completely built up and causes damage.

“It’s pretty visual because of the way propagation houses are designed. There’s an overlap between the area that the mist is covering,” Raudales says. “You tend to just visualize when the systems are off. But you just see some plants being slightly drier than the others and then you go to check to see if the [pipes] are clogged.”

Raudales also recommends testing the greenhouse’s water supply to evaluate the possibility of it becoming contaminated, and backing up the system. She suggests starting an ongoing, low-dose chemical treatment that can reduce buildup over time in the system. She also recommends installing a water filtration system.

“When we think about the way we grow in greenhouses, it’s kind of an industrialized type of factory production,” Raudales says. “We want to have a product that’s pretty even and we want to be able to have control over timing. You think about clogging, the main problem is that you’re losing control.”

Conversations are swirling these days around diversity in marketing campaigns. Brands of all sorts of products are working — or being pushed — to better represent a broader base of customers in their advertisements. Companies are swiftly held accountable by social media users when they get it wrong. Consumers have their eye on you and whether or not your marketing efforts make them feel included.

In this industry, we all win when more people garden and feel a connection to plants. Yet, how people love and use plants is evolving — as is who is engaging with plants. Your marketing reflects who you are inviting to the conversation. Have you built a big enough tent for everyone who wants to come to the garden party?

Challenging stereotypes is the first step to shaking up dated marketing. Who is the modern-day plant enthusiast and future gardener? Who is the modern-day and future homeowner, or business owner? What do they look like? Are they male or female? Where and how do they live?

As the world becomes more multicultural, and as women continue to strive for meaningful representation, younger consumers expect to see such change reflected in what they buy. Difference and diversity are looked upon much more favorably by younger consumers and they expect brands to be more inclusive. Men love houseplants, too — and women build landscapes. Some plant lovers — or wannabe plant lovers — use a wheelchair. And guess what? They aren’t all white.

If you spend any time watching TV these days, you’ll be hard pressed not to notice the sudden predominance of ads featuring multi-racial families, nontraditional family dynamics and representation of people with disabilities. The biggest brands in the world are doubling down on diversity. Plant growers and retailers need to take their cue.

Beyond these questions of diversity in demographics is one that might matter even more to us as an industry: Who qualifies as a gardener, and what qualifies as a garden? For me, gardening=one plant + one pot. If someone is growing just one plant, in any capacity, I consider it gardening in terms of how they are included in our marketing conversation. Broadening the definition of gardeners, garden-making and plant-keeping, is crucial for the green industry in an ever-urbanizing environment.

While you’re busy ignoring them, your target customers might just be generating their own marketing content around your product to better fit their own narrative. User generated content (UGC), such as video and social media posts, is nothing to sneeze at. At most of the grower and garden center retail-related talks I gave over the past year, I asked attendees if they used and followed Instagram — not many hands were raised. Well, I hate to tell you, but the plant keepers of Instagram are driving almost most of the marketing behind the current houseplant craze — not the industry. And they are apparently doing it completely behind your back.

If you want to know what’s going on in the marketplace — and how your customers want to use your plants and products — you will at least have to be a social media observer. Even if you aren’t engaging heavily on channels like Instagram, you’d better at least be looking at them.

Now, authenticity in marketing and advertising is a must. Pandering won’t get you far these days and how you market should make sense given what you sell. Relevance is required. Be thoughtful about how you proceed and make sure your message connects with real people and real needs. Be mindful about how your message impacts your ideal consumer’s mindset.

Most importantly, your marketing needs to drive actual sales. So while I am encouraging you to evaluate who you are including, or excluding, in your marketing efforts, you still need to make sure you’re hitting the right target. If you haven’t created a marketing plan for your company or product, which includes detailed information on your ideal customer, that’s a good place to start.

While you might think it’s not your business as a brand to get involved in social issues such as diversity — your customers might think otherwise. Remember: At a base level, most consumers want to see themselves reflected in the brands they buy, and they are looking for meaningful connections. As a brand, you have power to impact and shape ideas beyond just the plants and products you sell. There’s responsibility embedded in that power.

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