Last week, I spent 2,759 words on poinsettia problems you and your team might face in the next few months. It occurred to me that all that negativity was taking a “glass-half-empty” approach, which is very much NOT like me.

While I was scrolling back through the 185+ Tech On Demand podcast archive searching for poinsettia ’casts, I found a very cool and upbeat three-parter released last year that I want to share this week to change the vibe.

In this miniseries, GrowerTalks’ editor-in-chief Bossman Beytes took the mic and asked three poinsettia experts—Gary Vollmer from Selecta One, Rebecca Siemonsma of Express Seed and Steve Rinehart with Rinehart Poinsettias—to share what they consider to be the VERY BEST poinsettias for a wide range of grower and retailer needs.

Chris asks about every possible use—early- to late-season, small to large pots, best core reds and novelty colors, best varieties for regions from Fairbanks to Miami—and he asks them to pick regardless of breeder! He even asks which competitor's variety they wish was in their catalog, which variety they wish had never been bred, and which variety is the best poinsettia of all time.

Gary, Rebecca and Steve have more than 100 years of poinsettia experience between them and know almost every variety introduced since St. Louis Red! Although it’s probably too late to order the varieties mentioned, these episodes should at least get you fired up about what you’re growing this season and why poinsettias should be loved by all.

THE BEST POINSETTIAS FOR … (PART 1)—Best for early-season, autumn, big box programs, core reds and minis.

THE BEST POINSETTIAS FOR … (PART 2)—Best for tree-types, straight-ups, cut flowers, IGCs, fundraisers and natural/compact.

THE BEST POINSETTIAS FOR … (PART 3)—Best by color, most unusual, old-school varieties and … the best poinsettia of all time.

Be sure to subscribe to the Tech On Demand podcast on your favorite app so you never miss an episode. And if you’re not a regular listener, jump back into the archives and get caught up—there are 190 episodes (as of today).

• TECH ON DEMAND ON SPOTIFY
• TECH ON DEMAND ON APPLE PODCASTS

Western flower thrips (WFT) aren’t typically a major issue on poinsettias, except when a newly potted crop is placed in a house with an existing WFT population. WFT leaf strikes are not uncommon early in the season and typically disappear as new leaves unfold and cover the younger, thrips-damaged leaves.

However, two more damaging thrips species, Echinothrips americanus and Thrips parvispinus, need to be on your radar in 2025. This is especially true for greenhouses that held flowering tropicals, tropical foliage plants or spring annuals earlier in the year.

E. americanus, aka poinsettia thrips, is native to Eastern North America and has been around for over a hundred years. Until 2018 it mainly hung out on weedy plants and was rarely observed on poinsettias. In recent years it gravitated from weeds and native plant species to colocasia, syngonium, gerbera, sunflower, marigold and other ornamental plants as it moved west across the eastern half of the U.S. As a foliar feeder, it is easily observed on the upper or lower sides of leaves, with severe damage presenting as a yellow halo on older leaves.

Not sure if you have E. americanus? We recommend using Wet Green Horiver, developed by Koppert in 2022 to monitor for and mass-trap this species.

T. parvispinus, aka pepper thrips, is native to the Asian tropics and was first detected in Florida in 2020. In recent years it’s made its way north and west, traveling on flowering plants to garden centers across the country. Though it prefers dipladenia, mandevilla, gardenia, hoya and other flowering tropical and foliage plants such as schefflera, T. parvispinus is polyphagous: able to feed and reproduce on a wide variety of ornamental plant species. Feeding on leaves, flowers and developing fruit of food crops, it causes severe damage and deformity.

Monitor for this thrips species using Dry White Horiver, developed by Koppert in 2023 to target T. parvispinus.

Both of these thrips species cause significant crop damage when not detected and controlled. Poinsettia is one of more than 40 ornamental and food crops that serve as host to T. parvispinus, and there are more than 100 plant species known to host E. americanus, so don’t be caught unprepared.

Reach out to a Koppert technical consultant for more information on monitoring for and managing these problematic thrips species on poinsettias.

Each week, I’ll work with my buddy Nick Flax, a technical services expert at Ball, to share a concern that’s come up during one of his numerous calls with growers across North America. This week he’s shining the proverbial spotlight on a summertime pest that I don’t see written about too often—the Colorado potato beetle.

PROBLEM: Some years, I get a lot of calls from growers who have questions about a less-common but important pest, so now’s a good time to put it on your radar. If you still have veggie transplants on the bench or have gotten questions from retail customers on critters munching tomatoes and peppers bought from your greenhouse, this one’s for you. Gowers who primarily produce fresh market solanaceous crops will likely be familiar with this one, but if you’re predominately a floriculture grower who does veggie starts and has ventured into large patio pot veggies, this one may be new to you. Let’s chat about the Colorado potato beetle (CPB).

NICK’S TIP: True to its namesake, the CPB (Leptinotarsa decemlineata) is a major pest of potatoes in North America, but any member of the Solanaceae family is in the crosshairs of this critter. For many of you growing traditional floriculture crops, this means your pepper, tomato, tomatillo and eggplant starts (or patio pots) are prime targets.  

Identification  

Adults are roughly 1/2 in. long and 3/8 in. wide with rounded backs and glossy yellow forewings that have five black stripes running lengthwise along each (10 stripes total).  

Immature larvae look slightly hump-backed, have black heads, and are reddish in color, with two rows of black spots running along each side of their bodies.  

Mature larvae look similar to immatures (black heads, black spots) but are more of a pinkish-salmon color and are slightly larger. 

Life Cycle

Overwintered adults often emerge in late April (this depends on your location, as further south may emerge sooner) and feed for a short time before mating and laying eggs. Eggs are laid on the undersides of solanaceous host plant leaves in clusters of 20 to 30 or so. Eggs are generally brightly colored, often an orangish-yellow, and hatch about two weeks after they are laid.

Larvae feeding and rate of development is heavily dependent on average daily temperature, but they can fully develop in as few as about 10 days under warm temps (mid-80s F). Mature larvae then burrow into the soil to pupate and emerge again in about 10 to 14 days. In the northern US, typically only one to two of these cycles occur, but several more generations can occur in a single season the further south you go. 

Management

Adults overwinter along the edges of gardens and production fields on solanaceous weeds, such as common nightshade, horsenettle and “volunteer” peppers or tomatoes that have re-seeded themselves. So manage weeds and possible reservoirs on your property to reduce adult population from one season to the next.

While hand-removal is time-consuming and generally undesirable, picking adults off plants when scouting and dropping them into a solution of soapy water is effective. Scraping egg masses off the undersides of leaves when scouting is also helpful. 

Insecticide resistance is frequently a challenge when managing CPB, and many are resistant to active ingredients like carbaryl, imidacloprid and pyrethrins. Bioinsecticides containing Beauvaria bassiana (like Botanigard and Mycotrol) can provide control of both adults and larvae. Azadirachtin and Spinosad are also effective at managing CPB. 

A couple weeks ago, I shared a short VIDEO from Syngenta that walks you through growing African marigolds to hit Day of the Dead holiday sales. In the past week, I’ve shared it with a handful of growers and sales reps and received a few requests for a longer-form video taking a deeper dive into marigold production. It sounds like there are plenty of growers out there who might not grow African marigolds for spring but really want to have a crop to offer retail or wholesale customers for Día de Muertos on November 1 and 2 this year.

If this is the case at your greenhouse, you’re in luck. We released a video last year taking African marigolds from transplant to finish, with specific fall production tips and tricks weaved throughout.

In FINISHING AFRICAN MARIGOLDS: FOLLOW THE RULES!, Dr. Will Healy explained that African marigolds and French marigolds are like oranges and grapefruits when it comes to production protocols—meaning they’re similar (like the two citrus fruits) but also very different. He detailed the steps from plug transplant to shipping, with a particular focus on iron toxicity related to phosphorous deficiencies, tips for minimizing stretch to avoid the need for too many PGRs, nutrition to keep them growing strong, and how to avoid Botrytis in the flower heads. Will has worked with many growers dealing with leaf spots, and his advice on phosphorous is based on hundreds of crops and decades of experience.

I know this is an early announcement, but summer gets busy and we all have digital calendars—so put this live stream on there and REGISTER TODAY. That way you won’t forget. The date is August 27 and the time is 1 p.m. Eastern/Noon Central.

Most of you probably know that using pre-emergence herbicides can help reduce overall hand-weeding and spot-spraying weed-control costs. Envu recently sponsored a third-party study that looks at the actual costs, and savings, that you can expect from a comprehensive weed control program. The results show which products and practices offer the greatest return for your investment. The results also show this: Your greatest cost is the cost of neglect!

We have two guest experts lined up for this live stream webinar. Janna Beckerman, Ph.D., is the ornamentals technical specialist at Envu and part of their Green Services Team. Prior to Envu, she worked at Purdue University and the University of Minnesota as a professor of plant pathology and extension plant pathologist for 25 years. Steve Larson, Greenhouse and Nursery Specialist for Envu, has worked as a grower and a technical sales rep in the turf & ornamental industry for more than 40 years. He‘s worked in container nursery production, greenhouse crop production, and technical sales while working for Hines Nurseries, The Scotts Company, BASF and Envu (formerly Bayer).

Chris Beytes will be your host and moderator for this informative webinar!

REGISTER TODAY!

Many of you are probably reading this just before (or maybe even en route to) Cultivate’25 in Columbus, Ohio. I’ve made my schedule and once again it’s going to be a busy show! But I made sure to carve out plenty of time to walk the aisles and talk to as many of you as possible—whether you're attending or exhibiting. If you happen to spot my name badge, stop me in my tracks and say hello! I’m always happy to chat about the newsletter, podcasts or videos, and hear any ideas you might have for future content.

For now, I’ll close with a reminder to keep tracking your mum and poinsettia crops using the many tools available. Here are three to check out:

• GARDEN MUM GROWTH TRACKING
• POINSETTIA TRACKING TOOL
• DUMMEN ORANGE ON TARGET

Hope to see you in Columbus! And I’ll talk to you next week.