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 17, 2015

Sakata Seed Uses California Spring Trials Display Plants To Give Back

Sakata Seed America is putting its post-CAST (California Spring Trials) plants and flowers to good use to support events in local California communities of Salinas and Morgan Hill. The plants, along with donations through Sakata's Charitable Giving Program, will support three fun-filled community events that promote healthy lifestyles and support the agricultural industry.

Read More
Hakonochloa macra Aureola v

April 17, 2015

Ornamental Grasses — A Few Thoughts

Grasses have been embraced by growers, landscape architects and retailers, and are an important component in wholesale and resale sales. Allan Armitage shares some popular grasses, one to avoid and a few to use with caution.

Read More
PW_CAST15

April 17, 2015

Allan Armitage’s Favorite Plants From Proven Winners, Syngenta And Danziger

Between visiting California Spring Trial giants like Proven Winners, Syngenta and Danziger, Allan Armitage saw a lot of great plants in one day. Despite the size of the challenge, Dr. Armitage finds a few favorites he thinks you should try.

Read More
Latest Stories

April 15, 2015

BASF’s Pageant Intrinsic Fungicide Registration A…

The state of California has approved the supplemental label registration of Pageant Intrinsic brand fungicide for disease control in the commercial production of greenhouse-grown tomatoes and tomato transplants for the home consumer market.

Read More
Egg card used for insect control in Parkway Garden’s retail area.

April 13, 2015

Biocontrols Use Requires Commitment

For some companies, a switch to biocontrols is an easy decision to make. Parkway Gardens of Ontario, Canada, began using biocontrols nine years ago after Erik Jacobsen, the company’s owner, wanted to expose Parkway, its customers and the environment to fewer pesticide products. “Many pesticides were increasingly ineffective, and in Canada, new product registration moves with glacial slowness,” Jacobsen says. “The labor cost of applying pesticides is much greater than using biocontrols.” In addition, it was also an opportunity to market the company’s eco-friendliness to a younger demographic, he says. In a Q & A with Greenhouse Grower, Jacobsen explains what biocontrols and methods have proved effective for Parkway Gardens Greenhouse Grower: In what types of greenhouse structures are you using biocontrols? Erik Jacobsen: Our greenhouses are all poly covered. About half the range is a Westbrook 14-foot at peak gutter-connected block, and the remaining half a mix of quonset-style […]

Read More

April 11, 2015

Lowe’s Announces Commitment To Phase Out Neonicotinoids…

Home improvement retailer Lowe’s companies announced April 9 that it has committed to eliminate neonicotinoid pesticides from its stores in a gradual phase-out over the next 48 months. In response, horticulture industry associations issued a statement that Lowe’s position is surprising, considering the most recent and positive reports on the state of honeybee health and recent peer reviewed research, and that this is an issue for which sound science must take priority.

Read More

April 9, 2015

Survey Snapshot Shows Biocontrols Mainstreaming

Have you incorporated biocontrols into your greenhouse operation? If so, you’ve got plenty of company. An anonymous online survey by Greenhouse Grower magazine in December 2014 of more than 156 ornamental plant and flower growers across the U.S. found 81 percent used biocontrols in 2014.

Read More

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