Poinsettia, Euphorbia pulcherrima, is widely grown in greenhouses throughout the U.S.A., and like many greenhouse-grown horticultural crops, poinsettias are susceptible to a number of insect and mite pests. Therefore, it is important to effectively manage insect and mite pests on poinsettias, especially before bract formation, because very few insecticides and miticides are labeled for poinsettias when in bract. The insect and mite pests of poinsettias feed on the roots, leaves or stems, and bracts:

Roots: fungus gnat larvae;

Leaves and stems: whiteflies, western flower thrips, broad mites, Lewis mites, and mealybugs;

Bracts: western flower thrips;

This article provides a brief description of the damage to poinsettia plants associated with each insect and mite pest. In addition, the article discusses the plant protection strategies that should be implemented to manage insect and mite pest populations, which will help to prevent damage to poinsettia crops.

1. Fungus gnats

Fungus gnat, Bradysia spp., larvae (Figure 1) feed on root hairs and small roots, which inhibits the ability of poinsettia plants to obtain water and nutrients. Fungus gnats are primarily a problem under propagation when low larval numbers can kill cuttings or young plants. Cultural control and scouting practices associated with fungus gnats include the following:

Cultural: 1) avoid keeping the growing medium excessively moist, 2) remove weeds and old growing medium from around the production area, and 3) use either pasteurized or bagged growing medium.

Scouting: 1) use yellow sticky cards to capture fungus gnat adults, which will help to detect early infestations, and 2) use potato wedges to detect the presence of fungus gnat larvae.

A number of insecticides can be used to suppress fungus gnat larval populations in the growing medium, including insect growth regulators [e.g. pyriproxyfen], contact insecticides [e.g. chlorfenapyr], and microbials [Bacillus thuringiensis subsp. israelensis]. In addition, there are three biological control agents that are effective against fungus gnat larvae, including the rove beetle, Dalotia coriaria, the predatory mite, Stratiolaelaps scimitus, and the entomopathogenic nematode, Steinernema feltiae. The three biological control agents must be released before fungus gnat larval populations reach damaging levels.

2. Whiteflies

The sweet potato whitefly, Bemisia tabaci, is the primary insect pest of poinsettias, feeding within the vascular system (phloem sieve tubes) and removing plant fluids with their piercing-sucking mouthparts. In addition, the nymphs excrete honeydew, which is a clear, sticky liquid that serves as a substrate for black sooty mold. Whiteflies typically feed on the underside of poinsettia leaves (Figure 2). Furthermore, all the life stages (eggs, nymphs, pupae, and adults) are located on the leaf underside. The cultural control and scouting practices affiliated with whiteflies are the following:

Cultural: 1) remove weeds from within and around the greenhouse, 2) avoid over-fertilizing poinsettia plants with water-soluble nitrogen-based fertilizers, and 3) remove leaf debris from production areas.

Scouting: 1) use yellow sticky cards to capture whitefly adults, which will help to detect early infestations, and 2) visually inspect the underside of leaves for the presence of eggs, nymphs, and pupae.

Contact insecticides [e.g. cyfluthrin], insect growth regulators [e.g. pyriproxyfen], selective feeding blockers [e.g. pymetrozine], and systemic insecticides [e.g. dinotefuran] can be used to suppress whitefly populations. In addition, the parasitoid, Eretmocerus eremicus, can be released early in the production cycle to regulate whitefly populations. Furthermore, entomopathogenic fungi, including Beauveria bassiana and Isaria fumosoroseus, are effective against whiteflies when applications are made early in the crop production cycle. However, be sure to thoroughly cover leaf undersides with spray applications where all the life stages (eggs, nymphs, and adults) are located.

3. Western flower thrips

Western flower thrips, Frankliniella occidentalis, larvae and adults cause direct damage to the leaves and bracts of poinsettia plants that results in leaf scarring and distortion (Figure 3). Cultural control and scouting practices, which are designed to minimize problems with western flower thrips, include the following:

Cultural: 1) remove heavily infested or damaged plants, 2) screen greenhouse openings, such as vents, with insect micro-screening, and 3) remove all weeds from within the greenhouse.

Scouting: 1) use yellow sticky cards to capture adults, which will help detect early infestations, and 2) shake leaves over a white sheet of paper (8.5 x 11 inches) to detect the presence of larvae and adults.

A number of insecticides can be used on poinsettias prior to bract formation to suppress populations of western flower thrips, such as spinosad, chlorfenapyr, pyridalyl, and abamectin. Insecticides that can also be used include Beauveria bassiana, Isaria fumosoroseus, and spirotetramat. Always apply insecticides early in the crop production cycle and repeat applications, if needed, based on scouting information

4. Broad mites

The broad mite, Polyphagotarsonemus latus, is 1/100 inches long and its eggs have bumps on the surface. A dissecting microscope will allow you to actually see the mites on plant leaves. Broad mite feeding causes distortion or deformation of the terminal leaves of poinsettias (Figure 4). If you suspect broad mites are responsible for the damage observed on poinsettia plants, send samples to a diagnostic clinic for verification. Cultural control and scouting practices for broad mites include the following:

Cultural: immediately remove all plants that are suspected to be or are exhibiting damage caused by broad mites.

Scouting: routinely inspect plants for any visible damage that may be associated with broad mites.

Pesticides with miticidal activity may be used to manage broad mite populations, including abamectin, bifenazate + abamectin, chlorfenapyr, fenpyroximate, pyridaben, spiromesifen, and spirotetramat. However, these pesticides must be applied before damage is observed, otherwise it may be too late.

5. Lewis mites

The Lewis mite, Eotetranychus lewisi, is not a common pest problem of poinsettias, but greenhouse producers should be aware of this mite pest. The Lewis mite resembles the more common twospotted spider mite, Tetranychus urticae, in appearance, but is smaller. Lewis mites feed on the lower leaves and cause damage on poinsettias that may resemble a nutritional deficiency (Figure 5). The cultural control and scouting practices for the Lewis mite are the following:

Cultural: 1) remove all weeds from within the greenhouse that may serve as an alternate host plant for Lewis mites and 2) avoid over-fertilizing plants with water-soluble nitrogen-based fertilizers.

Scouting: 1) visually inspect leaf undersides for the presence of Lewis mites and 2) shake leaves over a white sheet of paper (8.5 x 11 inches) to detect the presence of Lewis mites.

Miticides with contact or translaminar activity (material penetrates leaf tissues and forms a reservoir of active ingredient within the leaf that provides residual activity after spray residues have dissipated) can be used against Lewis mites, as well as certain biological control agents, including predatory mites and the predatory midge, Feltiella acarisuga. Check miticide labels to determine those that are registered for use against the Lewis mite. Furthermore, consult with your biological control supplier to determine which predatory mites should be released to regulate Lewis mite populations.

6. Mealybugs

Mealybugs are not a major pest of poinsettias; however, they have become more of a problem. One possible reason is that systemic insecticides applied to the growing medium may not be effective against mealybugs on poinsettias. Therefore, mealybug populations may build up and potentially displace other insect pests, such as whiteflies, that are susceptible to systemic insecticides. Mealybugs feed on the leaf underside, on the plant stem (Figure 6), and near the base of the petioles. Like whiteflies, mealybugs feed within the vascular system, removing plant fluids. Mealybugs can cause leaf distortion, plant stunting and wilting. Also like whiteflies, mealybugs excrete copious amounts of honeydew, which serves as a substrate for black sooty mold. The cultural control and scouting practices associated with mealybugs are the following:

Cultural: 1) immediately dispose of heavily infested plants and 2) avoid over-fertilizing plants with water-soluble nitrogen-based fertilizers.

Scouting: visually inspect plants for mealybug life stages, including nymphs (crawlers) and egg-laying females. Mealybug populations may be suppressed on poinsettia plants before bract formation using insecticides such as acetamiprid, pyrifluquinazon, flupyradifurone, mineral oil, and buprofezin. However, multiple applications will be required, and thorough coverage of leaf undersides and plant stems is important.

In conclusion

A number of insect and mite pests may feed on poinsettia plants during the growing season. However, greenhouse producers can alleviate problems with these insect and mite pests by implementing a multitude of plant protection strategies, including cultural control, scouting, pesticides, and/or biological control. Another strategy used by many greenhouse producers involves installing Yellow Stiky Tape™ among a poinsettia crop, which will capture adult fungus gnats, whiteflies and western flower thrips. The use of the Yellow Stiky Tape may help reduce insect pest populations below plant-damaging levels. Always be proactive when dealing with insect or mite pests that feed on poinsettias, especially before bract formation, as options are limited once poinsettias are forming bracts.

Raymond A. Cloyd is a professor and extension specialist in horticultural entomology/plant protection in the Department of Entomology at Kansas State University, rcloyd@ksu.edu.

In July, Greenhouse Management magazine conducted a survey to learn how growers across North America administer pest management plans, budget for insect control, scout for pests and much more. Our survey of more than 300 growers revealed which pests growers battle most often and how they manage controls programs. See how your peers handle insect management.

Editor’s note: Due to rounding, not all percentages add up to 100.

As always, it is an honor for Bayer to sponsor this special issue of Greenhouse Management. In an ever-changing industry, it is more important now than ever for ornamental growers to embrace new solutions, take advantage of innovations and leverage valuable insights. Carefully examining important trends, like the ones in this edition, helps us focus on what matters: bringing innovative ornamental solutions and expertise to support your growing business.

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From humble beginnings in an oversized garage to the regional retail powerhouse it is today, Petitti Garden Centers has seen explosive growth since it got its start in 1971. Ranking No. 2 on Garden Center magazine’s Top 100 list, the nine-store regional chain is celebrating 50 years of learning, growing, renovating, educating and changing the way Ohioans garden.

What started as a small landscape company evolved over the years from pop-up shops in grocery parking lots to state-of-the-art, European-inspired garden centers, acres of growing space both indoors and out, and a reputation for quality.

“It’s been a lot of work and it hasn’t happened by accident,” says Petitti Garden Centers founder and owner Angelo Petitti. “It’s a big milestone for us, for the family, for all the employees and the whole organization.”

50 years in the making

Angelo may come from a family of farmers but he didn’t get his first landscaping experience until he came to the U.S. At just 16 years old, he emigrated from a small town in Southeast Italy in 1963 and moved in with his uncle, who was an avid gardener. When the uncle had a stroke, Angelo went to work in his yard and got his first taste of landscaping.

Around the same time, Angelo was working as a busboy at a high-end nightclub and one of the waitresses there become his salesperson as he did some landscaping jobs for customers.

From those customers, he went on to found Petitti Landscape Company in 1966 and spent the next four years building his clientele. When he and his brother Domenico bought a location in Oakwood Village for their landscape business in 1969, passers-by started asking if they could buy the plant material the brothers would set out for their landscape jobs. Landscaping would remain the dominant source of income for the company until 1988, but the retail idea was planted.

Back in the ‘80s, Angelo bought all of his plant material, and would have to order the year before and collect his plant material by April 15. “So every year when it came to April 15, you either took it or you lost it,” he says, noting that inventory in the ‘80s was extremely tight, just like it is now.

“Back then the business was quite different,” Angelo says. “We didn’t have quite the array of varieties and all of the basket and container world was kind of minimum compared to what it is today.”

So Angelo would take the material and deal with the Cleveland area’s unpredictable spring weather.

“It seems like financially, it never really benefitted the company to where you would maximize the profits off of that,” he says. “That’s where the idea of starting to grow our own really came from.”

In 1989, Angelo started working on the nursery side of the horticulture world. One year later, the company had its own plant material to sell out of the renovated Oakwood headquarters. “It was a rough start,” Angelo says. “I knew nothing about growing. I was not a grower, so it was a bumpy start.”

In 1991, Angelo hired a grower and started to build the company its propagation house. By 1994, the business was seeing the financial benefits of growing its own material and never looked back. “So growing definitely opened up our eyes so say this is really the key that really built the business side,” he says.

Going all-in on the greenhouse investment, Angelo built brand new greenhouses at the Oakwood location in 1993, and just two years later, he was out of growing space in the 5-acre site. So when a close friend, John van Wingerden, founder of Green Circle Growers in northern Ohio, decided to get rid of one of his facilities, Angelo snatched it up and with John’s help, grew the greenhouse side of the business to where it is now, Angelo says.

“When we took this over, we were way over our heads,” AJ says. “I mean we went from the kiddie pool to the big boy pool real quick.”

But today, the grower-retailer produces enough plant material to stock all nine of its stores without buying in any green goods.

Growing more plants, capturing more business

While it was a huge jump to dive headfirst into the greenhouse business, Angelo says that risk is what got Petitti to where it is today, giving the company the tools and the volume of plant material it needed to be financially stable.

But growing their own meant they had to find a way to sell it all.

“We could grow so much and we really had to figure out how to market this product, so every year we would come up with different ideas,” he says.

And that’s when Petitti really started to push the envelope on the Northeast Ohio growing season. In the ‘90s, sales in Ohio tended to end around June 1, but Petitti started to extend the season and grow plants for the summer months. Angelo says it took customers about three years to get accustomed to the extended gardening season.

“That was kind of the culture and that’s what customers were trained to do. They were trained that when June 1st came or Memorial Day was done, the season was over,” Angelo says. “So when we started growing for the month of June and then July and August, it got us to the next level. We were growing annuals, but we really expanded the varieties, the selection, the quality — and we came up with new programs every year. And the same thing with perennials.”

The history of Petitti Garden Centers in photos

Since Petitti Garden Centers doesn’t do any wholesale sales, the company had to find ways to move everything it grew or eat the cost. So they found unique pots, hanging baskets, containers and customized programs that worked for their unique retail situation. And today, the IGC is famous for its hanging baskets.

“It gave us this huge advantage over everybody else and the biggest difference today is when you come in here and you look around, the variety is endless,” Angelo says. “That’s how strong our brand is — when you go to Petitti’s, your biggest problem is trying to figure out what to buy because there’s so much there to choose from.”

And while the huge selection can be a challenge for the consumer faced with so many options, it’s that unique variety that keeps customers coming back. “It’s really that the selection is so different than any place else,” Angelo says, noting that the stores have also evolved over the years to become lifestyle centers with furniture, food, clothing, gifts and more.

But the real driving financial engine is the Casa Verde greenhouses and farms that stock the IGCs and give them the funds to keep each store state-of-the-art, he says. “We really take a lot of pride in keeping everything up to the highest level. But the financial means that really come from the growing.”

From greenhouse to garden center

Petitti Garden Centers and its affiliated growing operation Casa Verde Growers has spent years streamlining the greenhouse to garden center process to eliminate the potential for logistical mistakes.

Before plants even leave the Casa Verde greenhouses or nursery fields, their information is loaded into the Petitti point-of-sale system so that they’re priced and ready to go. Then they’re off to the stores, pre-priced, with their exact location noted.

That streamlined process is part of the reason Petitti doesn’t order any of its plant material from other suppliers. The individual stores order what they need and the process is seamless. That’s particularly important since Casa Verde can ship 15 to 20 semitrucks a day to the stores during the spring season.

“The amount of labor that saves us and the readiness for retail is perfect. When you get the material there, it’s ready to be sold,” Angelo says. “You don’t have to go through a process before you get it onto the floor. We don’t have to order anything. Everything is sort of ordered on the internet automatically so there’s no phone calls, no salespeople, there’s nobody we have to call. So everything is set up for us to handle in our own way. It just happens automatically.”

The detailed POS and management system also ensures that the stores never run out of supply.

Online sales

When COVID first hit the U.S. last year, Petitti was lucky enough to remain open, but the online store became more important, as it did for many in the industry. The big difference Petitti Garden Centers has seen is the amount of pre-visit browsing shoppers are doing online.

“They’re going to the site and you can kind of see when we’ve got sales or promos, if there’s a spike in a different category,” AJ says. “And we can back that up with web analytics.”

The site took about eight months to put together because thankfully, the company had already put years of work into its tag program and had information ready and available to upload. They were able to copy and paste the information onto the website, along with their huge cache of photos, some from their on-staff photographer and some dating back to earlier days when Angelo’s wife and AJ’s mother Maria took the store photos.

“We’ve got huge photo banks, I mean, thousands of SKUs. And so a lot of that content that is really the hardest part to generate, we already had generated. And so that’s how we were able to take that and just plug it right in,” AJ says.

“In any business, you always have to play the long game. It’s never been the short game. You just keep investing and investing and investing,” Angelo adds. “And the time will come that you reap these benefits.”

The marketing team really took control of the site and took it to the next level, increasing digital marketing and e-commerce, which creates a great package and experience for customers, AJ says, but the majority of their efforts are focused on bringing customers into the stores. So while customers can see the price points and the inventory, not everything is available online.

And the information available on the site goes far above and beyond the average online store. The graphics team brands everything with Petitti photos from their on-staff photographer, and each plant description is tailored specifically for the Northeast Ohio gardener.

“It takes all of these pieces in order to make it work, and make it work well,” Angelo says. “And it takes a while to get to that point. It’s not something that happens overnight. And you have to have the financial capabilities to support that. One thing that we have done and will also do is be heavy on the marketing side. We will spend way more than the industry, even when we were doing $30-35 million a year, we were still spending a very high percentage on marketing.”

Marketing through education

Along with robust online information, Petitti Garden Centers provides several other avenues for gardeners to learn, get inspired and be successful in their own gardens. From Angelo’s radio show that’s 40 years in the running to the Gardening with Angelo seasonal magazine, to community outreach, local news spots and more, the Petitti name is well known throughout Northeast Ohio.

“We really focus very heavily on the community and very heavily on the education side. We always believe that in order for you to build the brand, you need the community and you need the marketing and you need to back it up with the product,” Angelo says. “You can market all you want, but in the end, the product has to back that up.”

Investing in education is important in-store as well. The company revised its entire tag program so that each plant is labeled with information specific to the Northeast Ohio area, but the process took years to collect all of the pertinent information.

“When you look at a nursery tag, it’s so general, they’ll give you a height of 2 to 8 feet. Well, is it 2 or is it 8?” Angelo says.

So Noelle Akin, director of education, customized all of the information for Petitti’s clientele. “It was really confusing for the customer,” Angelo says. “So we invested in that and that’s the kind of investment we’ve made for years over and over. The bottom line is we want our customers to be successful.”

Predicting demand

Despite supply chain issues that are plaguing many IGCs and a competitive labor market, Petitti Garden Centers is poised for another great year of sales, building on the big success of last year’s surge in garden interest.

“We did a really good job of getting ahead of things, working with our suppliers, getting that product lined up so that we had it when we needed it this spring and going through summer,” he says, noting that Petitti buyers saw trends coming early. “So I think we’re really well-positioned not only to go through spring and have a strong season but continue to be strong through summer. Because the demand is there.”

On the supply side, Petitti is seeing cost increases and slower timelines than usual, so buyers have had to be “really on top of it,” AJ says. At the regional garden center, they’re thinking six to 12 months in advance. This year, the IGC is ordering new stock before they’ve even put merchandise for 2021 out on the floor.

“And there’s a lot of risk with that,” AJ says. “But if you don’t do that, I don’t think you’re going to get the product.”

The next 50 years

From its humble beginnings to the nine state-of-the-art locations it has today, Petitti Garden Centers is in a constant state of growth. “The building has never stopped,” AJ says. “I don’t think there’s been a year that we have not built. One way or another, it’s different levels and different areas or new equipment but there’s always something going on.”

With AJ ready to lead the company into the next 50 years, the management might change but the values will remain the same — great plants, great service and eyes on the future. AJ says he’s going to honor the same core values they always have. And, of course, they’ll be looking at the business every day and finding ways to improve and grow.

“It all starts from the foundation and the foundation is set on: just be focused on the business to get better and better and do things the right way every day,” Angelo says. “So if you do things right, if you do the right thing every day, chances are that people are just going to keep coming to the store.”

This article originally appeared in the June 2021 issue of Garden Center magazine. This article has been edited for length and relevance to the greenhouse market.