Easter Lily Leaf Unfolding Technique Royal Heins, Department of Horticulture, Michigan State University

Transcription

1 1 5+ years of Service UM I MNLA Minnesota Coercial Growers Bulletin Noveber 22 - Page 15 Easter Lily Leaf Unfolding Technique Royal Heins, Departent of Horticulture, Michigan State University Leaf counting is a technique used to insure proper tiing of a lily crop. Once a lily shoot initiates a flower bud, no ore leaves will for. At visible bud, all the leaves have unfolded. Therefore, if one knows how any leaves have yet to unfold on a plant before the visible bud stage, one can calculate how any leaves ust unfold each day (or work) in order to reach the visible bud stage by a particular date. By knowing the nuber of leaves which ust unfold each week and by aking a count of leaves which actually unfolded the previous week, one can deterine if a crop is slow, fast or on tie. Subsequently, the air teperature ay be increased or decreased to hasten or delay plant developent for proper crop tiing. The following describes how to leaf count a lily crop. 1) Leaf counting is usually started 3-4 weeks after eergence or when plants are 3-4 inches tall. The first plants are exained to deterine if flower initiation has occurred. If the first plants exained are still vegetative, a new set of plants is exained 4-5 days later.. 2) A iniu of 3-5 plants for every bulb source and bulb size should be taken to estiate the average leaf nuber of the crop. Count how any leaves have unfolded and how any leaves have yet to unfold on each plant. Unfolded leaves are norally defined as those leaves which are at an angle equal to or greater than 45O with the plant ste. Leaves yet to unfold are defined as those leaves which have an angle of less than 45 with the plant ste. The actual leaf angle is less iportant than consistency between countings. A large needle and a agnifying glass will help you reove sall scale-like leaves near the shoot apex. The e- bryo-like flower buds will be present on reproductive plants. An estiate of the future bud count can be ade on these plants. 3. Divide the nuber of leaves already unfolded by the nuber of days fro eergence until the present date. This will tell how any leaves have unfolded each day to date. 4) Deterine the visible bud date. The visible bud date is norally 3-35 days prior to the expected flower date (often the week prior to Pal Sunday). It takes 3 days fro visible bud to flower at 7 F (21 C) and 35 days at 65 F (18 C). Not all plants reach visible bud the sae day. 5) Divide the nuber of leaves which have yet to unfold by the nuber of days fro the day of leaf counting until the expected visible bud date. This figure tells you how any leaves ust unfold each day to achieve visible bud at the desired tie. 6) If the nuber of leaves to unfold each day is greater than the nuber of leaves unfolded each day fro eergence until the day of counting, then the average greenhouse air teperature should be increased. In contrast, if the nuber of leaves to unfold each day is saller than the nuber of leaves unfolded each day prior to leaf counting, the average air teperature should be decreased to slow developent. 7) In the greenhouse, ark the last unfolded leaves on several representative plants of each lot and bulb size. Different ethods can be used. They include arking each unfolded leaf with a agic arker or hole punch or by placing a wire hoop above all expanded leaves on the shoot but below the yet unexpanded leaves. We recoend the use of a wire hoop. 8) Every 3 to 4 days (twice a week) count and record the average nuber of leaves unfolded, calculate the daily unfolding rate. Copare the days and deterine if the leaf nuber was higher or lower than that which was necessary for proper tiing. Adjust greenhouse teperatures accordingly. 9) The rate of leaf unfolding is a linear function of the average teperature delivered to a lily crop over tie. In other words, the increase in the rate of leaf unfolding resulting fro 55" to 6 F is the sae as that fro 7" to 75 F.

2 Page 16 - Noveber 22 UM / MNLA Minnesota Coercial Growers Bulletin 5+ years of Service I. Basic Inforation: Arrival Date Bulb Source Bulb Size Easter Lily Crop Log (April 2, 23) 11. Bulb Inspection and Soil Test: Excellent Good Fair Poor Roots Basal Plate Scales Test edia prior to planting bulbs. Attach soil test analysis. IV. Planting and Cooling Info: Planting Date Cooling Treatent Initiated Cooling Treatent Copleted V. Fungicide Application Schedule: Date Applic. 1 Applic. 2 Applic. 3 Applic. 4 VI. Leaf Nuber and Calculated Leaves per Day: Total Leaf Nuber Days To Visible Bud Leaves per Day Needed to VII. Final Developental Data: Leaf Nuber Nuber First Plant Height at

3 5+ years of Service UM / MNLA Minnesota Coercial Growers Bulletin Noveber 22 - Page 17 Prefinished Easter Lily Schedule Production Year An increasing nuber of Easter lily growers are purchasing prefinished Easter lily plants. A prefinished plant has alreadq been cooled, the shoot has eerged and, in general, flower initiation has occurred. In soc cases flower initiation has not if plants arrive prior to January 28. A schedule for a prefinished crop is presented belou. Critical issues that a forcer ust contend with when receiving prefinished plants includc: tlic cooling treatent and flower initiation is conducted by soeone else thus taking uch ot the control 1 tlouering out of the forcers hands. In addition, the final leaf nuber is greatly ipacted by the cooling ethod used and can. therefore, greatly aff ect the schedule in the forcers facility. It is. therefore. critical that a forcer specify and/or know the exact procedures for cooling in order to iniize any difticult) that niaq occur during forcing and to axiize final quality. We assue that prefinished product Mill he sold as a retail crop..january 28 1;ebruary 17 March 12 March 19 March 26 1) initiation is coplete 2) Leafcount 3) Change day and night teperature to achi.e desired leaf unfolding rate and DIF. Apply growth retardants as needed. Drench with fungicide for Pyihiwn. l ~ ~ i ~ ~ i o ~ ~ Spray Fascination to lower 113 of plant I ) Visible Bud 2) Space plants if possible 3J Apply fungicides for both J~~ihii. l~~i~~io~?~l~ and Rhizocloniu. Spray Fascination to lower 1/3 of plant April 13-2 April April 2 Easter

4 Page 18 - Noveber 22 UM / MNLA Minnesota Coercial Growers Bulletin 5+ years of Service Wholesale Lily Schedule Production Year October Noveber ) Bulbs Arrive 2) Pot Bulbs, Fertilize with 4 pp nitrogen l ro ;i 3) Drench with fungicide for HO T II /~v/hiz/~ii and Rhizoclonitr 4) Grow at F nicdia tepcraturc 1) Start Cooling Treatent (42 F-6 weeks) 2) Drench with fungicide for l ylhiu, 1 hjlophlhoi.tr Deceber January 3-1 1) Place plants in 6547 F greenhouse 2) Pot Bulbs, Fertilize with 4 pp iiilrogcii 1to ;I 3) Drench with fungicide f or I ylhiuiii, I h~~io~?hilior~ct and Rhizoctoniu 4) Grow at F edia teperaturc 1% of shoots should be eerged January 2 January 28 February 17 March 1 March 17 March 24 1 ) initiation is coplete 2) Leafcount 3) Change day and night teperature to achieve desired leaf unfolding rate and DIF. 4) Apply growth retardants as needed. I ) Drench with fungicide for / ~~hiiii~i. / Ii~~io~~~i~lioi Spray Fascination to lower 1 /3 of plant 1 ) Visible Bud 2) Space plants if possible 3) Apply fungicides for Pythiiiiii and Khizocloniu. Spray Fascination to lower I13 of plant April April 14 April 2 Easter

5 SO+ years of Service UM / MNLA Minnesota Coercial Growers Bulletin Noveber 22 - Page 19 Wholesaler Easter Lily Schedule (Early for Storage) Production Year October Noveber ) Bulbs Arrive 2) Pot Bulbs, Fertilize with 4 pp nitrogen fro a 3) Drench with fungicide for BOTH Pythiu and Rhizoctonia 4) Grow at F edia teperature 1) Start Cooling Treatent (42OF-6 weeks) 2) Drench with fungicide for Pythiu, Phytophthora and Rhizoctonia. Deceber January 3-1 January 13 January 28 February 1 March 2 March 9 March 16 April 4 April April ) Place plants in 6567 F greenhouse 2) Pot Bulbs, Fertilize with 4 pp nitrogen fro a 3) Drench with fungicide for Pythiu, Phytophthora and Rhizocton ia 4) Grow at F edia teperature 1% of shoots should be eerged 1) Drench with fungicide for Pythiu, Phytophthora and Rhizoctonia. 1) initiation is coplete 2) Leaf count 3) Change dav and night teperature to achieve desired leaf unfolding rate and DIF. 4) Apply growth retardants as needed. 1) Drench with fungicide for Pythiu, Phytophthora and Rhizoctonia. Spray Fascination to lower 1 /3 of plant 1) Visible Bud 2) Space plants if possible 3) Apply fungicides for Pythiu, Phytophthora and Rhizoctonia. Spray Fascination to lower 1/3 of plant Place in cooler for storape (45'F with lights) Ship

6 Page 2 - Noveber 22 UM / MNLA Minnesota Coercial Growers Bulletin 5+ years of Service Retailer Easter Lily Schedule (Noral) Production Year October Noveber ) Bulbs Arrive 2) Pot Bulbs, Fertilize with 4 pp nitrogen ii-o a 3) Drench with fungicide for Pylhiir. I hi lol,l.llhol.tr and Rhizoctoniu 4) Grow at 6567 F edia teperature 1) Start Cooling Treatent (42 F-6 weeks) 2) Drench with fungicide for l y/hiiiiw l li ~ioi~iii~i~)i.~l Deceber January 3-1 January 2 January 28 February 17 I 1) Place plants in 6567 F greenhouse 2) Pot Bulbs, Fertilize with 4 ppin nitrogcn flo a 3) Drench with fungicide for l?;ihiuni. l h?~iophiholu and Rhizoctoniu 4) Grow at 6567 F edia teinperature 1% of shoots should be eerged 1 ) Drench with fungicide for Pj~hiiii~i, l li~~io~~ili~~o 1) initiation is coplete 2) Leafcount 3) Change day and night teperaturc to achiecc desired leaf unfolding rate and Dl F. 4) Apply growth retardants as needed. March 12 March 19 March 26 April 13-2 April April 2 r Spray Fascination to lower 113 of plant 1 ) Visible Bud 2) Space plants if possible 3) Apply fungicides for Pylhiuni. Phj /oyhlhor.tr and Rhizocloniu. Spray Fascination to lower 113 of plant Retail Easter

7 5+ years of Service UM / MNLA Minnesota Coercial Growers Bulletin Noveber 22 - Page 21 Retailer Easter Lily Schedule (Early for Storage) Production Year October Noveber 4-1 I 1) Bulbs Arrive 2) Pot Bulbs, Fertilize with 4 pp nitrogen fro a 3) Drench with fungicide or Pylhiuiii. Phyiophihoru and Rhizocloniu 4) Grow at 6567 F edia teperature 1) Start Cooling Treatent (42 F-6 weeks) 2) Drench with fungicide for l:yihiu. Phylophlhortr Deceber Januarj 3-1 January 13.January 28 1) Place plants in 6567 F Preenhouse 2) Pot Bulbs, Fertilize with 4 pp nitrogen fro a 3) Drench with fungicide for Pylhiuni. 1 hjvophihor.u and Rhizoctoniu 4) Grow at 6567 F edia teperature 1% of shoots should be eerged 1 ) Drench with fungicide for Pythiuni. I /ijiophrhoru and R h izoct o n iu. 1) initiation is coplete 2) Leafcount 3) ChanPe day and night teperature to achieco desired leaf unfolding rate and DIF. 4) Apply growth retardants as needed. 1 ) Drench with fungicide for Pylhiuni, Phj~loph/horu March 2 March 9 March 16 April 4 April 13-2 April 16 Spray Fascination to lower 1/3 of plant 1) Visible Bud 2) Space plants if possiblc 3) Apply fungicides for Py(hiu. Phl lot)hilioi.ci and R hizoct oniu. Spray Fascination to lower 1 /3 1 plant Place in cooler for storage (45 F with lights) Retail

8 Page 22 - Noveber 22 UM I MNLA Minnesota Coercial Growers Bulletin 5+ years of Service Case-Cooled Easter Lily Schedule Production Year Case cooled bulbs are usually cooled by the broker. Bulbs arrive and are potted icdiatelq. 1:ergencc and rooting occur siultaneously. In general, case cooled bulbs will have reduced leaf six and ilowr nuber coinpared to CTF or naturally cooled bulbs. Bulbs will typically arrive iti niid-l>ecebcr. Deceber ) Place plants in 6S-67 F greenhousc 2) Pot Bulbs, Fertilize with 4 pp nitrogen l ro ;I 3) Drench with fungicide for i j-/h;u. i ~j /o/iliilir,/.li and Rtiizodoniu 4) Grow at F edia tcpcratiirc January 3-1 1% of shoots should be enicrgcd January 2 Drench with fungicide for i$thiuiii, / ~i~.iol llillol.li Januarv 28 1) initiation is coplete 2) Leafcount 3) Change day and night teperature to achick c desired leaf unfolding rate and Ill F. 4) Apply growth retardants as needed. February 17 March Spray Fascination to lower 1 /-3 of plant March March April April April 2 I) Visible Bud 2) Space plants if possible 3J Apply fungicides for l ylhiuni. l ~~j~~o~~~lilloi.~~ and Rhizoctoniu. Spray Fascination to lower plant Shir,, Ship and Retail Easter

9 5+ years of Service UM / MNLA Minnesota Coercial Growers Bulletin Noveber 22 - Page 23! SUN MON TUE WED THU FRI SAT i 113! 7 l4 Bulbs Arrive I 28 SUN SUN MON TUE WED THU FRI SAT Stop Cooling ^_- 17 Move to Greenhouse! F Media

10 Page 24 - Noveber 22 UM / MNLA Minnesota Coercial Growers Bulletin SO+ years of Service 1 SUN MON TUE WED THU FRI 1 SAT 3 1% /4 i Eergence 11 i SUN 1 MON TUE WED THU I FRI SAT Iz' I I i

11 5+ years of Service UM / MNLA Minnesota Coercial Growers Bulletin Noveber 22 - Page 25 SUN 1 MON I TUE 1 WED THU FRI 3 5 / SAT I Easter /22 j i 3 I Move into Cooler - NOV out of Cooler - Dec. 16- Ship and/or Plant Initiation Jan. 3-1 Mar. 17 Oct Vernalize at 42 F Eergence Jan. 28 A Visible Bud Apr

12 Page 26 - Noveber 22 UM / MNLA Minnesota Coercial Growers Bulletin 5+ years of Service The Easter lily bud eter was developed to help growers deterine how uch tie will be required before an Easter lily will flower. Place the eter at the base of the flower-not the flower stalk. 1.e. where the petal eets the peduncle. Read across to see the nuber of days required until flowering. Reeber that the least aount of tie required froni visible bud until flowering is 24 days. In other words, if your crop is not at visible bud 24 days prior to Easter, it will not ake it! Easter Lily Bud Meter G..* E cu rc r N..Tt.... (D b._.. W ' 'a7 :,i.. 2 b, ' -7-1 T- a hl. " G r- I.- 3i 4YS l- N d '1' rc W, l- 2 d 7- (D 7-9- c\i In..w... ~.....r. c\l ~.~~.~.~.~.~.~.... d.. d * -*. r.. cu.p. v). * ~..., ' 5....: ( o r - = d a..$!ft...r z... co- r..a.....g.. l-.a.. r c v r e3 b. T z v. 9 ' $ cv... In hl N O.. or-g,g..%... s. E?..a -- E a Y Q) e".* 9 a -..C E '2,.s 8 v).w r v) al.- I-.L al C v) W. -a ' C z.-- L * Q)' # e * L.' % c. a' zi Place tapered end ofeter.at the base of the Easter lily flower bud. Observe where the tip of the bud falls on the eter, which corresponds to the nuber of days to flower at the specified teperatures (Fisher et al., 1996).

13 5+ years of Service UM / MNLA Minnesota Coercial Growers Bulletin Noveber 22 - Page 27 (continued fro page 14-Root Rot) fungicides. I have coe across growers who can control root rot entirely through water and edia anageent. However, ost of us will need to apply cheical fungicides. Apply fungicides for BOTH Pythiu and Rhizoctonia control. Rotate fungicides to reduce the chance of resistance. There is significant Subdue resistance evident in greenhouses this past year. Therefore, ake sure that your fungicide progra includes Truban. There is no docuented resistance to Truban as of yet. I suggest the following rotation on a onthly basis starting after potting: I) Subdue (1/2 211 gallons) + Cleary s 3336 (8 211 gallons), 2) Banrot ( gallons), 3) Truban (8211 gallons) + Terraclor (8 211 gallons). If another application is needed, start at the beginning of the rotation again. Crowding Plant crowding can significantly decrease crop quality at the end of a production cycle fro visible bud until flowering. Typically, ste elongation increases and there is ore lower leaf loss. There appears to be a relationship between total light and probles related to crowding where there is ore lower leaf loss under low light conditions. Solution: Space plants if possible. Spacing allows for ore light to reach the lower leaves and allows ore air oveent to liit the possibility of root rot. Recent research has shown that application of Fascination a week before and a week after visible bud to the lower leaves only will reduce lower leaf yellowing. Therefore, if you don t have the space to space, apply Fascination. Scheduling: Plants can flower too early or too late when plants are not grown at appropriate teperatures between Jan. 28 (flower initiation) and the visible bud date. Inexact scheduling usually occurs because a grower has not counted the leaves yet to unfold and then delivered the average daily teperature to achieve the desired leaf-unfolding rate. Solution: Count leaves around January 28. Deterine how any leaves need to unfold per day by the visible bud date. Monitor the leaf-unfolding rate of your crop on a weekly basis. Adjust average daily teperature to achieve the desired leaf-unfolding rate. Articles in this bulletin go through the process in ore detail. Over or Under cooling: In general, a lily crop should receive 6 weeks of cooling at 42oF. If lilies are cooled for less tie, we say they are under cooled and plants will be taller, have ore flowers, be less unifor and take flower to flower. If lilies are cooled for longer than 6 weeks, we say they are overcooled and plants will have fewer leaves and flowers, have short lower leaves, and will flower quicker. If bulbs are cooled at teperatures above or below 42oF for 6 weeks they will be overcooled! If bulbs are iature when you start cooling, it is possible for bulbs to be under cooled even if you cool for 6 weeks at 42oF. Solution: Prior to cooling, bulbs should be aintained at teperatures above 63F. Once you put plants in a cooler, place a soil theroeter in the edia in the cooler and adjust cooler teperature to achieve 42oF. Cool for exactly 6 weeks. Early Shoot Eergence While in the Cooler: Shoots can eerge in the cooler if dorancy is broken early and ste elongation starts before cooling is coplete. This can be a significant proble in dark coolers and/or coolers in which pots are stacked in such a way that no light reaches each pot. As a result, there can be excessive shoot elongation resulting in a coplete loss of product. Solution: Drop teperatures on a weekly basis for 1-2 days to 36F to inhibit elongation. Provide fluorescent or daylight in the cooler to inhibit elongation. Stack plants in the cooler in such a way as to insure that 1) you can see if early shoot eergence is occurring, 2) to allow light to reach the surface of the edia, and 3) dup a pot periodically to see if elongation of the shoot is occurring before the shoot breaks through the edia surface and drop teperatures periodically to liit shoot (pin) eergence.