Height Control For Easter Lilies

Figure 1. 'Star Gazer' oriental lilies (size 16/18 bulbs) treated with 4.0-fluid-ounce drenches providing flurprimidol at 0.0 to 4.0 mg a.i. per pot. Applying a single drench of 0.5 mg active ingredient (a.i.) per pot or two split applications of 0.25 mg a.i. controlled excessive stretch of Oriental lilies.

Height control is one of biggest challenges in potted Easter lily production. There are several factors that contribute to the difficulty in controlling Easter lily height, including: year-to-year variation in bulbs, the date Easter falls on and, of course, the weather.

All of these factors work together to make each year’s Easter lily crop a unique challenge. Fortunately, there are several tools available for growers to control unwanted stem elongation. For instance, a warmer night air temperature than day air temperature creates a negative DIF (DIF is day temperature minus night temperature), which has been shown to minimize stem elongation of Easter lilies.

However, with today’s high energy costs, it can be cost prohibitive. Therefore, a more practical and economical tool is to control stem elongation using plant growth regulators (PGRs).

While flurprimidol is a PGR that has been available in Europe for more than 20 years as a 1.5-percent formulation, it has been recently introduced into the U.S. market as a 0.38-percent formulation (Topflor, SePRO). Flurprimidol has a similar chemical structure to ancymidol (Abide, A-Rest) and a degree of activity and uptake comparable to paclobutrazol (Bonzi, Piccolo, Paczol) and uniconazole (Concise, Sumagic) in which it can be absorbed by both roots and shoots. As a result, flurprimidol can be applied as a foliar spray, liner dip, bulb dip, and/or substrate drench.

Flurprimidol drenches have been shown to successfully control height of oriental lilies and Dutch bulbs such as hyacinth, narcissus and tulips. However, there is no published information on using flurprimidol drenches on Easter lily. As a result, we wanted to see if flurprimidol drenches would successfully control Easter lily height.

The Experiments

Experiment 1 (North Carolina State). Case-cooled ‘Nellie White’ Easter lily bulbs (9/10 size) were potted, one bulb per pot, in 6-inch-diameter round plastic pots filled with a soilless substrate. The substrate contained 75 to 80 percent Canadian sphagnum peat and 20 to 25 percent perlite (Berger BM 6; Berger Peat Moss).

Plants were placed in a greenhouse under natural day lengths with day and night temperature set points of 68 and 65°F, respectively. Plants were fertilized weekly with 150 parts per million (ppm) N using 15-0-15. When shoots were about 3 to 4 inches tall, a single 4-fluid-ounce drench was applied to the substrate surface of each pot providing flurprimidol at 0.02, 0.04, 0.08, 0.16 or 0.24 mg active ingredient (a.i.) per pot or uniconazole (Sumagic; Valent USA) at 0.03 or 0.06 mg a.i. per pot. Untreated controls were also included.

Experiment 2 (Purdue). Case-cooled ‘Nellie White’ Easter lily bulbs (10/12 size) were potted, one bulb per pot, in 6-inch-diameter round plastic pots filled with a soilless substrate, which contained 80-percent Canadian sphagnum peat and 20-percent perlite (Fafard 1P; Conrad Fafard). Plants were placed in a greenhouse under natural day lengths with a constant air temperature set point of 65°F. Plants were fertilized with 200 ppm N using 15-5-15 at each irrigation. When shoots were about 3 to 4 inches tall, a single 4-fluid-ounce drench was applied to the substrate surface of each pot, providing flurprimidol at 0.01, 0.02, 0.04, 0.06 or 0.08 mg a.i. per pot. Untreated controls were also included.

What We Saw

Overall, flurprimidol was effective in controlling stem elongation of Easter lily in both experiments, with subtle differences in the results. In Experiment 1 at North Carolina State, as the amount of flurprimidol increased from 0.02 to 0.24 mg a.i. per pot, plant height was 9 percent (2.4 inches) to 59 percent (15.6 inches) shorter than untreated plants (Figure 2). While drenches providing 0.02 to 0.08 mg a.i. flurprimidol resulted in plants of a commercially acceptable height, applying 0.16 or 0.24 mg a.i. flurprimidol provided too much control. When 0.03 or 0.06 mg a.i. of uniconazole was applied to each pot, plant height was 8 percent (2.2 inches) and 36 percent (9.4 inches) shorter, respectively. Neither flurprimidol nor uniconazole drenches had any effect on flower bud number or time to flower as compared to the untreated controls.

For Experiment 2 at Purdue, we observed a similar trend in height in response to flurprimidol to that seen in Experiment 1. For instance, as the amount of flurprimidol applied increased from 0 to 0.08 mg a.i./pot, stem elongation was suppressed by 25 percent (Figure 3). Similar to Experiment 1, flurprimidol drenches had no effect on flower bud number or time to flower. While we did observe some lower leaf yellowing, this was not due to the PGRs, but to slight overwatering as a result of all treated Easter lilies being on drippers with the same irrigation program.

Using Flurprimidol Drenches On Easter Lilies

Based on what we observed, flurprimidol drenches can be an effective PGR treatment to control Easter lily stem elongation without affecting time to flower or flower bud count. In order to maximize the benefits of a flurprimidol drench on Easter lilies, there are a few key points to remember. First, apply drenches when the growing substrate is moderately dry. In doing so, you won’t lose any of the PGR from leaching out of the bottom of the pot.

Secondly, be sure to apply a sufficient volume of solution to each pot. For example, for a 6-inch standard container, 4-fluid ounces is the suggested volume of solution. The amount of active ingredient applied will also depend on the pot size, number of bulbs per pot and bulb size.

As observed in Experiment 2, larger bulbs (i.e. 10/12) may require more PGR than smaller bulbs (i.e. 9/10) to achieve the desired growth control.

Lastly, time your applications correctly. For best results, apply drenches to Easter lilies when the shoots have emerged approximately 3 to 4 inches above the surface of the growing substrate.

Flurprimidol drenches are not only effective at controlling Easter lily stem elongation, they may also be effective in controlling your production costs. If you currently drench your Easter lilies with uniconazole, you will find a cost savings by using flurprimidol. With the drench rates of the two chemicals being similar for comparable control, a flurprimidol drench application costs 60 to 80 percent less than uniconazole due to the percentage of active ingredient in the formulation and cost of the chemicals (Figure 4).

Other Flurprimidol Application Options

If growers want to continue using foliar sprays, how does flurprimidol compare? Flurprimidol rates of 80 ppm, applied twice, controlled excessive stretch in limited trials conducted in the northern U.S. It must be emphasized that the trial size was small, and further in-house trialing should be done before that rate is used by commercial operations. At this point, it appears the lower rates of uniconazole may still be the preferred foliar spray option for Easter lily growers.

We have also conducted extensive pre-plant bulb soak trials with flurprimidol on Easter lilies. Easter lilies are extremely responsive to flurprimidol. We found the optimal rate window to be very narrow, so much that the year-to-year variation in bulb lots makes it impossible to provide a consistent optimal rate. At this point, we are reluctant to recommend flurprimidol pre-plant bulb soak for Easter lilies.

Takeaways

Remember, always start with a small-scale, on-site trial in your greenhouse when using new PGR applications to see what works optimally for you and your production methods. This is especially important with Easter lilies that have a great amount of year-to-year variation. Our research results provide a starting point for your in-house trials. You may also want to trial lower drench rates of flurprimidol to provide initial control, and then follow up with uniconazole spray applications as needed to finish off the crop. Flurprimidol drenches clearly control stem elongation of Easter lily and may be a useful addition to your toolkit for controlling stem elongation of Easter lily.

Leave a Reply

One comment on “Height Control For Easter Lilies

  1. I have had many growers asking about the TopFlor conversion to Parts per million and a simple way to convert is to multilpy the mg/ai by the number eight. For example .02 mg/ai = .16 ppm. Most northern growers can find good results at .16 ppm – .24 ppm as a drench at 2" spike, which is likely soon with the April 9th 2012 Easter. There is a cost savings of between 25% and 50% vs. Uniconizol.

More From Crop Inputs...

April 1, 2015

Philadelphia Flower Show Draws More Than 250,000 Attendees With Disney Pixar Movie Theme

With more than 250,000 consumers attending the prestigious Philadelphia Flower Show in March each year, it's a great opportunity to get flowers and gardening products into the public eye. This year's show displays took on family favorites at the movies, with a focus on Disney and Pixar films. Check out some of the highlights in our slideshow.

Read More

April 1, 2015

Peace Tree Farms Grows Its Customer Base

Over the past five years, Peace Tree Farms in Kintnersville, Pa., has concentrated on growing its business by providing plant material for the displays at the illustrious Philadelphia Flower Show. We caught up with Peace Tree Farms’ Lloyd Traven to ask about how the Flower Show figures into his business plan.

Read More
protecting bees and pollinators video

March 31, 2015

New Video On Protecting Bees And Pollinators Educates Horticulture Industry Professionals

A new educational video that provides information on the horticultural industry’s essential role in bee and pollinator stewardship is one result of industry collaboration by the Horticultural Research Institute, AmericanHort, Society of American Florists and the American Floral Endowment. “Protecting Bees & Pollinators: What Horticulture Needs to Know,” narrates the current state of bee and pollinator health, provides information on factors that impact pollinators and the environment and underscores the beneficial role horticulture plays in providing healthy pollinator ecosystems.

Read More
Latest Stories

March 31, 2015

Manufacturers Are Taking Biologicals To The Next Level

Through acquisitions and new products, many crop protection companies are making firm commitments to the future of the biocontrols industry.

Read More
OxiPhos_BioSafe2

March 23, 2015

BioSafe Makes Label Changes To OxiPhos And ZeroTol 2.0

There have been some recent label changes made to the BioSafe Systems product OxiPhos, a systemic bactericide/fungicide that reduces downy mildew spores when tank mixed with ZeroTol 2.0.

Read More
Nufarm_logo

March 23, 2015

Nufarm Fungicides Now Registered For Use On Edible Crop…

Nufarm Americas announced label expansions for two of its fungicides that will provide more pest management options for the ornamental industry. The Cleary 3336 F and EG fungicides are now registered for use across a wider range of edible crops, including select greenhouse vegetables and transplants, herbs and backyard fruit.

Read More
ColeusDMLeafSporulation_Daughtrey

March 11, 2015

Research Gives Clues For Preventing Coleus Downy Mildew

Maintaining awareness of coleus downy mildew is more important than ever to safeguard these attractive plants for reliable garden performance.

Read More
Rose Rosette on Knockout rose, May 2013. Photo credit: Alan Windham, University of Tennessee

March 2, 2015

Rose Rosette Disease Fight Gets A Boost From Government…

In 2014, $4.6 million was awarded through the Farm Bill to tackle rose rosette disease, a devastating pathogen that affects one of the industry’s most important crops.

Read More
Fig 1 Leafy Gall On Leucanthemum Becky

March 2, 2015

How To Prevent Leafy Gall Before You Lose Plants

Leafy gall is a nasty disease that can go undetected until plant damage is done. Take these steps to protect your crops from infection.

Read More

February 17, 2015

A New Look At Biological Control: Can Plants Affect The…

The success of a biological control program depends on a number of factors including quality of natural enemies, timing of release, release rates and environmental conditions. However, what is typically not taken into consideration is how plants can affect the performance of natural enemies, including attack rate and searching ability. Biological control agents work hard to protect plants, but plants have ways to help themselves, too.

Read More

February 1, 2015

New Pest Control Products For Your Toolbox

Add one of these new insecticides to your IPM program for successful pest control.

Read More
IR-4_profile_Feb2015

January 29, 2015

IR-4: A Pest Management Resource For Growers

Almost 40 years ago, IR-4 (Interregional Research Project Number 4) began serving the ornamental horticulture industry, helping to facilitate the registration of pest management tools. IR-4 does this primarily by surveying growers about their pest management issues and then hosting workshops to review survey results and set priorities for the coming years. Most recently, IR-4 coordinated a meeting of researchers and industry members on pollinator health and neonicotinoid chemistries to start a discussion on the needed research. The next step will be to get the outcomes from that workshop out to the public.

Read More

January 28, 2015

Biocontrols 2015 Conference & Tradeshow: Peace Tree…

Lloyd Traven, a speaker at the upcoming Biocontrols 2015 Conference & Tradeshow, was one of the industry’s early adopters of biocontrols in the greenhouse. Traven, owner of Peace Tree Farm, is evangelical about the technology as an effective tool for resistance management, as well as improved plant quality that contributes to a grower’s bottom line.

Read More

January 27, 2015

Southwest Perennials Improves Production, Shortens Crop…

A father-and-son team find LEDs deliver a higher rooting rate for cuttings propagated under the lights.

Read More
Wainwright-web-620x349

January 22, 2015

Quality Control With Biocontrols

Make sure the shipment of beneficials that just arrived is viable and ready to go to work in your greenhouse, nursery, or field. Here are five steps you can take to ensure success with your biocontrols.

Read More

January 9, 2015

6 New Fertilizer Products For Healthy Plants

These five products add even more options for delivering nutrients to the root zone.

Read More

January 7, 2015

Fertilizers And The Future

As growers look for new ways to cut costs and conserve resources, fertilizer and equipment companies are offering products that strive to save water, reduce toxic runoff and keep chemicals out of the equation.

Read More

December 31, 2014

Gain Greater Control Of Fertilizer With Automated Ferti…

University researchers look at integrating irrigation and fertilization with the help of water sensors to reduce fertilizer treatments and improve application timing.

Read More
As directed by EPA, the bee hazard icon appears in the Directions For Use for each application site for specific use restrictions and instructions to protect bee and other pollinators.

December 9, 2014

Fact Sheet: The Value Of Neonicotinoids To Turf And Orn…

An extensive study of the diverse turf and ornamental industry (“The Green Industry”) reveals that neonicotinoids are the top-rated products used by professionals to control their most important pests in greenhouses, landscapes, lawns, nurseries and trees.

Read More
As directed by EPA, the bee hazard icon appears in the Directions For Use for each application site for specific use restrictions and instructions to protect bee and other pollinators.

December 9, 2014

New Study Finds Neonicotinoids Are Top-Rated Products F…

According to results of a survey by AgInfomatics, professionals in the turf and ornamental industries fear the loss of neonicotinoid products would reduce the quality of their plants and services, increase costs and negatively impact their ability to manage pest resistance.

Read More

December 2, 2014

Grow-Tech Announces BioStrate, Its Newest Hydroponic Gr…

Grow-Tech LLC recently announced the release of BioStrate Felt, a biobased textile specifically engineered for the growing of hydroponic microgreens and baby salad greens.

Read More