callafornia calla cultural guidelines for...

Tel: (831) 728-0500 Fax: (831) 761-1282 1260 Highway 1, Moss Landing, CA 95039 USA

www.goldenstatebulb.com / www.callaforniacallas.com

CALLAFORNIA CALLA® CULTURAL GUIDELINES for POT USE

REV. 03/2015

INTRODUCTION

Spring callas are known by many common names and combinations such as calla lilies, colored callas, mini-callas, colored mini-callas and Callafornia Callas

®. No matter what they are called, these elegant beauties are best recognized for their

classic, chalice-shaped flowers that now come in a wide array of colors and sizes. Though naturally spring flowering and summer deciduous, Golden State Bulb Growers’ Callafornia Callas

® are easily programmed for year round production.

The most traditional use for Callafornia Callas® are as cut-flowers (i.e. weddings, interior decorating, arrangements,

consumer/mixed bouquets etc.), landscape border plants and potted plants. There continues to be increasing popularity for the crop as a potted plant, due in part to the use of the plant growth retardant paclobutrazol (i.e. Bonzi, etc.) paired with GSBG’s development of fuller, more compact Callafornia Calla

® varieties and advancements in bulb production

technologies. Potted plants can be placed outdoors and/or planted in the landscape for extended enjoyment. Once established and where the ground does not freeze, spring callas are quite durable in the landscape and are often capable of returning year-after-year.

AVAILABILITY, HANDLING & STORAGE

GSBG’s Callafornia Calla bulbs are available for supply from mid-October through late September. Upon arrival, immediately unpack bulbs and place in well-ventilated trays to hold them at approximately 65°F (~18°C) for two days. This

will “heal off” any possible friction wounds that were caused in transit prior to planting. Dispose of any soft rot and wash hands to avoid spreading of bacteria to healthy bulbs.

Many growers prefer to receive bulbs in a bulk shipment that will be planted over the span of several weeks. This is often done with a variety of goals in mind such as improving freight logistics/reduced costs; flexibility in planting schedule/volume; meeting minimum order requirements.

Bulbs may also be stored for up to six weeks at 75-80% relative humidity but this requires modestly active air-flow to avoid penicillium (blue mold). Ideal storage temperatures depend on the timing of bulb supply. Please consider this as an option when planning your program(s).

Penicillium or “blue mold” will develop on bulbs subject to high humidity and too little air exchange/movement.

Excessive airflow in storage can lead to shrinking of bulbs and sprout desiccation.

Early in the shipping season bulbs should be held at 55-65°F (13-18°C), while those received later in the season should be held closer 50°F (10°C). Though longer sprouts may be suggestive that lower storage temperatures should be utilized, do not subject bulbs to storage conditions below 48°F (9°C). For best results, great care should be taken with “long-stored” bulbs received in September, as they should be planted promptly after receipt to avoid excessive sprouting, desiccation and/or weakening.

Placing bulbs upside-down in trays will further delay sprout elongation and improve durability at planting.

SCHEDULING

Callafornia Calla crop timing is based on numerous factors including duration of bulb dormancy; sprout length; seasonal forcing conditions (light/temperature); bulb size and varietal differences. “Fresh” bulbs supplied in October will generally flower in 13-14 weeks, while those supplied in September [of the following year] tend to flower in as few as 7-8 weeks. Table 1 below suggests the possible spectrum of crop timing in relatively high light Northern Hemisphere plantings.

TABLE 1: CALLAFORNIA CALLA SEASONAL CROP TIMING Valentine’s Easter Mother’s Day Summer Fall Christmas

13-14 weeks 11-13 weeks 10-12 weeks 9-10 weeks 8-9 weeks 7-8 weeks

◊ See GSBG’s Master Planning Document for additional details specific to relative varietal timing ◊

Extensive details on forcing conditions are found throughout this document with recommended environmental conditions provided later in the “Growth and Development” section. However, exact crop scheduling is somewhat challenging to precisely forecast due to fluctuations in seasonal/environmental conditions. Notably, warmer temperatures and longer days accelerate growth & development. Conversely, lower temperatures and light will slow the crop.

◊ See also “Light” and “Temperature” sections ◊ ◊ Please contact us for additional details and/or guidance ◊

When estimating sales/shipping readiness of potted plants, consider that as approximately 1/3 of the crop has flower spikes visible & elongating, then 75-80% should be ready in 10-20 days time depending on season, conditions and variety.

Most Oranges and “Bi-Colors” get darker with age; consider adding 5-7 days crop time on these for richer coloration.

Tel: (831) 728-0500 Fax: (831) 761-1282 www.goldenstatebulb.com / www.callaforniacallas.com

Callafornia Calla Cultural Recommendations (rev May 2015) Copyright 2015 GSBG - All rights reserved.

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BULB FORM, FLOWERING & PRE-TREATMENTS

Cluster vs. Dominant Bulbs:

Spring callas naturally develop different bulb forms that are generally classified as “clusters” or “dominants”. Clusters are broader, more compressed bulbs with variously attached daughter bulb offsets. Clusters develop multiple growing points around the main apical shoot, yielding more leaves and flowers. Plants produced from clusters have good “balance” and tend to transport at relatively high densities (full, compact and with correspondingly shorter stems). Conversely, dominants are rather deep and “round” bulbs that lack multiple attached offsets, resulting in few-to-no side shoots. Dominant bulbs tend to produce upright plants with few but larger, taller and heavier stemmed flowers. Though other spring calla bulb sources may often supply a variable spectrum of bulb forms, GSBG’s production technologies generate clustered, high performance bulbs to specifically serve commercial pot and cut-flower growers.

Floral Potential:

Provided that cultural inputs are good and plants remain healthy, Callafornia Callas are known for the highest floral productivity available in the marketplace. The total number of blooms per Callafornia Calla bulb will primarily vary depending on the variety, bulb size & form. Cultural inputs that will also have a significant impact on productivity are root space, moisture, fertility, temperature and light. Warm germination temperatures cause rapid and aggressive rooting that triggers eye stimulation & growth- a fundamental phase towards achieving optimal vigor and floral performance.

Greater growth & flowering is correlated with early vigorous root activity, modest fertility and relatively high light!

Influence of GA on Productivity:

Callafornia Calla bulbs arrive ready to force having already been pretreated with a variety specific GA formulation. With this GA (gibberellic acid) treatment you can expect twice as many, or more flowers as compared to an untreated bulb. Side effects from GA treatment include slightly increased plant height, slightly reduced leaf width and softened growth- especially in low light / shorter days and in combination with high N fertilization. Subsequent paclobutrazol (i.e. Bonzi, etc.) treatment will minimize these side effects.

Response will vary dependent on cultivar, environmental conditions and cultural inputs.

Stimulatory effects of GSBG’s GA treatment lasts several months on dormant bulbs, allowing for bulk order & storage.

Pretreatment Disease Suppression:

Callafornia Callas are pretreated with a proprietary synergistic blend of fungicides/bactericides intended to get plants off to a good start. We strongly recommend following up with preventative drenches as detailed later in the “Disease Prevention & Control” section.

Recycling Bulbs:

In the rare instance where you find yourself in the position of needing to recycle some product, please contact GSBG for specific recommendations. We would be happy to assist you.

MEDIA & CONTAINER SELECTION

Media Components & Properties:

Use a well draining media with a pH of 6-6.5. Good air porosity is critical to success; it’s best in the range of 20% ±5%. Peat based media should be of a “coarse grade” and in the range of 30-50% of the mix.

Experienced growers in pursuit of more “lush” and luxuriant growth sometimes use higher proportions of peat. This is done at the risk of enhancing disease pressure. Whether making you’re own mix or purchasing a premixed leading brand media, selection should be dictated by the need to hold peat levels down.

Sample Media: 3 parts Coarse Peat : 2 parts Large Perlite : 2 parts ⅛ - ¼” Firbark : 1 part Graded #2 Sand (as ballast)

Growers must accommodate for the early irrigation requirements including fungicidal & PGR drenches plus regular fertilization. In low transpiration environments (i.e. winter forcings) heavier or “greater water holding capacity” media can remain too wet and favoring soil borne diseases. Using lighter mixes or less peat in mixes during winter forcings allows for the frequent inputs during irrigations and “salt leachings”.

Various components that can improve media drainage are graded large particle perlite, coarse sand, coarse firbark,

pumice and scoria. Redwood sawdust should not make up more than 30% of a mix. Be careful to not “over-grind” components when mixing media; otherwise, a reduction of particle size can cause compaction that favor root pathogens.

Pine bark is known to variably tie up the PGR paclobutrazol and should be used with care or possibly avoided.

Graded No. 2 sand can help ballast “top heavy” pots/containers in windy conditions.

High quality and salts free Coir/Coco Peat has been used with mixed results. Occasional improvements in flower/stem quality have been observed in cut-flowers, while greater incidence of water molds (pythium) have been observed in pots. Use coir at your own risk and while carefully adhering to disease control protocols herein.



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Media Incorporants:

Lime, gypsum and dolomite aid to balance pH and also provide calcium for good plant health. A light two-week starter charge of a balanced fertilizer will help plants get off to an early start. We recommend media incorporation of biologicals such as Root Shield [Trichoderma spp.] or Soil Guard [Gliocladium spp.] at a rate of 1 lb/yd3 (593gm/m3). It’s best to incorporate these 3-7 days before planting to promote optimal root health, especially where fungicide labels are restricted.

◊ See also “Disease Prevention & Control” section ◊

Container Selection:

Relatively tall/deep containers with a “perforated oxygen cone” and “feet” can significantly enhance drainage characteristics for abundant rooting and continued root health. Landscape containers are best with “high feet” and/or “lateral” drain ports that improve drainage, particularly when production occurs on the ground/landscape cloth that may otherwise hinder drainage.

Always avoid the use of short/shallow pots; limited drain ports/area; no “foot” provision; drains on a “single plane” only.

PLANTING

Depth of Planting:

Callafornia Callas prefer deep, well-draining soil whether planting in raised beds or containers. Care must be taken to plant at proper depth since rooting exclusively occurs from the top of the bulbs. Planting too shallow can subject the root origin to dry and/or salt stress. Moreover, rooting will not effectively occur and corresponding eyes fail to develop or grow if the bulb is so shallow that it becomes exposed. This can affect a considerable portion of the plant and result in plants that are “one-sided” (i.e. performing at half their potential). Plant rounded side down and eyes/sprouts up with 1-1.5" (2.5-3.8 cm) of media over the bulbs.

Bulbs planted upside-down will result in plants that exhibit no “central” growth and deeper, wetter roots.

Orientation of Planting:

Bulbs should be planted nearly “flat” or on a horizontal plane. Very large bulbs may be planted at a slight angle to prevent water from pooling on the crown. “Multiple bulbs” should be planted relatively close together (i.e. 0.5-1” (1.25-2.5cm) apart and depending on pot & bulb size) to result in plants that emerge and grow with an integrated appearance.

Planting bulbs on their sides/vertically will produce growth like “fans” or “flatfish” (i.e. flounder/halibut).

Bulb & Pot/Container Size:

Clustered, high performance Callafornia Callas are available in a broad range of sizes. As a “rule for thumb”, the largest bulbs produce the tallest leaves and flowers with the heaviest stems and largest-cups. Conversely, the smallest bulbs produce the shortest leaves and rather “delicate” flowers with the smallest cups. The remaining “in between” sizes deliver a corresponding gradient of performance characteristics.

The greatest number of “offsets” and “florally potent” eyes are also found on the largest bulbs, resulting in higher productivity. However, “multiple bulb planting” with smaller sizes produces fuller and highly floriferous containers and often results in reduced PGR requirements plus better aesthetic balance.

Most spring callas are best suited to medium pots such as 1 gallon containers / 6-8" (15-20 cm) and larger pots or tubs such as 2 gallon containers / 10-12" (25-30 cm). GSBG’s Callafornia Calla

® collection is also distinguished by varieties

that are compact enough for 4-4.5” (10-11cm) containers, and even smaller! Refer to Tables 2 & 3 for bulb size & quantity recommendations specific various pot/container sizes. GSBG’s Master Planning Document provides additional specific details relative to varietal use by pot/container sizes.

TABLE 2: PLANTING MODEL by LANDSCAPE CONTAINER SIZE, BULB SIZE & QUANTITY

RECOMMENDED CONTAINER SIZE

(measured in diameter)

SINGLE BULB USE vs. MULTIPLE BULB PLANTING OPTIONS Bulb Size: inches dia. (cm circ.)

SPEC 1 BULB @ 2 BULBS @ 3 BULBS @ 4 BULBS @

quart (10-13cm) GCM 1.5-1.75" (12/14) 1.0-1.25" (08/10) n/a n/a

PRE 1.75-2.0" (14/16) 1.25-1.5" (10/12) 1.0-1.25" (08/10) n/a

gallon (17cm)

GCM 1.75-2.0" (14/16) 1.25-1.5" (10/12) 1.0-1.25" (08/10) n/a

SMF 2.0-2.25" (16/18) 1.5-1.75" (12/14) 1.25-1.5" (10/12) n/a

PRE 2.25-2.5" (18/20) 1+1 [1.5+1.75] 1.25-1.5" (10/12) n/a

2 gallon (25-30cm) GCM 2.5-3" (20/24) 1.75-2.0" (14/16) 1.5-1.75" (12/14) 1.25-1.5" (10/12)

PRE 3.0+ (24+) 2.0-2.25" (16/18) 1.75-2.0" (14/16) 1.5-1.75" (12/14)

◊ SPEC refers to proposed performance relative to market quality “GCM” / “SMF” / “PRE” (Garden Center/Mass Market; SuperMarket Floral; Premium Outlets) ◊

◊ Flower counts and fullness increase with the use of “multiple bulbs” ◊



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TABLE 3: PLANTING MODEL by FLORAL CONTAINER SIZE, BULB SIZE & QUANTITY

RECOMMENDED CONTAINER SIZE

(measured in diameter)

SINGLE BULB USE vs. MULTIPLE BULB PLANTING OPTIONS Bulb Size: inches dia. (cm circ.)

SPEC 1 BULB @ 2 BULBS @ 3 BULBS @ 4 BULBS @

3-3.5” (7.5-9cm)

GCM 1.0-1.25" (08/10) n/a n/a n/a

SMF 1.25-1.5" (10/12) n/a n/a n/a

PRE 1.5-1.75" (12/14) 1.0-1.25" (08/10) n/a n/a

4-5” (10-13cm)

GCM 1.5-1.75" (12/14) 1.0-1.25" (08/10) n/a n/a

SMF 1.75-2.0" (14/16) 1.25-1.5" (10/12) 1.0-1.25" (08/10) n/a

PRE 2.0-2.25" (16/18) 1.5-1.75" (12/14) n/a 1.0-1.25" (08/10)

6” (15cm)

GCM 2.0-2.25" (16/18) 1.5-1.75" (12/14) n/a 1.0-1.25" (08/10)

SMF 2.25-2.5" (18/20) 1+1 [1.5+1.75] 1.25-1.5" (10/12) n/a

PRE 2.5-3" (20/24) 1.75-2.0" (14/16) 1.5-1.75" (12/14) 1.25-1.5" (10/12)

8” (20cm) SMF 2.5-3" (20/24) 1.75-2.0" (14/16) 1.5-1.75" (12/14) 1.25-1.5" (10/12)

PRE 3.0+ (24+) 2.0-2.25" (16/18) 1.75-2.0" (14/16) 1.5-1.75" (12/14)

10-12” (25-30cm) SMF 3.0+ (24+) 2.0-2.25" (16/18) 1.75-2.0" (14/16) 1.5-1.75" (12/14)

PRE n/a n/a 2.0-2.25" (16/18) n/a

◊ SPEC refers to proposed performance relative to market quality “GCM” / “SMF” / “PRE” (Garden Center/Mass Market; SuperMarket Floral; Premium Outlets) ◊

◊ Flower counts and fullness increase with the use of “multiple bulbs” ◊

Smaller/shorter pot sizes like those 4” (10cm), and below, are generally more difficult to grow due to root volume restriction, reduced buffering to wet/dry fluctuations, increased frequency of irrigation cycles and correspondingly high salts levels. Such plants tend to be more easily stressed and are as a result, generally more disease prone. Careful attention to media porosity, fertility and irrigation practices are thus required.

GROWTH & DEVELOPMENT

Light: Callafornia Callas withstand a wide range of light conditions from 4,000 to 8,000 foot-candles (43,000-86,000 lux). Higher light can also be tolerated during cool, overcast & humid periods and/or short-day conditions. However, during warm, bright and long-day summer conditions, plants may flower prematurely due the rapid assimilation of PAR (photosynthetic active radiation). To prevent plants from flowering with too little growth, a 30% shade is recommended when days become “long” and light levels more intense.

The provision of shading during warm and bright “long-day” periods will aid in moderating both ambient and canopy temperatures while slowing PAR assimilation. This allows for gradual canopy growth & development so that flowering may occur at appropriate physical maturity.

Flower pigments (anthocyanins, carotenoids & xanthophylls) all intensify with high light [& cool mornings]

during flower budding, elongation and maturation. Low light [and/or warm] finishing conditions soften coloration.

Varietal Light Considerations:

Narrow-leaf varieties are generally more tolerant to lower light levels and limited space. Alternately, broad-leaf [yellow/orange] types require considerably more space and higher light levels for best results.

The compactness and floral productivity of Callafornia Callas is partially dependent on plants receiving adequate light levels to both canopy & crown. Very low light levels and/or crowded conditions may inhibit optimal flowering and/or require additional PGR’s to achieve proper height control.

Spring Callas are not photoperiodic nor do they require temperature treatments to induce bloom.

◊ See also “Temperature” and “Influence of GA on Productivity" sections ◊

Supplemental Lighting:

Assimilation lighting may be required in Northern Latitudes experiencing very low light levels (duration & quality) to enhance growth and increase baseline PAR received by plants. Metal Halide or High Pressure Sodium lamps must be used. Though systems engineered to provide 420-560 foot candles (4500-6000 lux) could serve as a minimum contribution, systems providing 930 foot-candles (10000 lux) will enhance crop quality and increase floral performance.

Far red light provided with incandescent night-interrupt systems actually will cause additional stretching.



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Temperature:

Callafornia Callas are rather robust growers that tolerate various temperatures. However, consistent temperature regimes for each “growth stage” and avoidance of temperature extremes will greatly enhance plant vigor, health and performance. Spring callas are frequently grown in controlled temperature greenhouses or automated cold frames during the winter/spring and under partial-to-full cover during warmer seasons/locations. Best results are obtained with an active germination period followed by “staged” temperature conditions as follows:

Stage #1: Root/Sprout Development for “Early/Mid Forcings” – Optimum germination temperatures are 75ºF (24ºC) days and 65ºF (18ºC) nights OR a constant 68ºF (20ºC). This stage occurs from planting to 1-3" (2.5-7.5cm) sprouts (approximately the 1

st 12-25 days [depending on season, conditions and variety]).

Providing early & even heat improves uniformity, vigor and determinance as each individual eye is stimulated to aggressively root then follow to correspondingly sprout, develop and flower.

Root/Sprout Development for “Summer/Fall Forcings” – Less germination and eye activation is required for

these later plantings as bulbs arrive with elongating sprouts. Uniform & stable conditions are best while moderating both germination duration and temperature (i.e. 10-12 days @ approximately 65ºF (~18ºC)).

Avoid subjecting crop to high temperatures for best results.

Growers with an inability to provide suggested germination temperatures should consider alternative methods.

Alternative A: Place crop in a high-density germ room “racked & stacked” for ONLY 8-12 days at the

specified temperatures. This offers significant energy savings and results in uniform root stimulation that is necessary to activate each and every eye… the first steps towards optimal performance.

Alternative B: Placing a semi-permeable cover over the crop can be an alternative to stabilize both

temperatures and humidity. Use a perforated “remay” (spun frost cloth), topped with light mil plastic during the early germination phase. Though remay may remain in place until sprouts are up to 1-2” (2.5-5cm) long, plastic must be removed as soon as sprouts break the surface to prevent disease pressure.

Excessive germination temperatures and/or duration can reduce leaf count and fullness (= petiole production).

PGR’s are traditionally applied when sprouts reach a 0.5-2” (1.25-5cm) above the soil.

◊ See also “PGRs (Plant Growth Regulators)” section for revised strategies ◊

Stage #2: Foliage Growth/Canopy Development – Optimum growth and development is achieved with 70º-75ºF (21º-24ºC) days and 55-60ºF (13-16ºC) nights. Begin this stage approximately one week after sprouting, often coinciding with

initial PGR application, continuing through leaf expansion and canopy development (approximately from day 14-28 to day 50 [depending on season, conditions and variety]).

A COLD PULSE may be considered at this stage to synergize with paclobutrazol to control plant height. This can be initiated at 2-5 days after 1

st PGR application.

◊ See also “Negative DIF/Morning Cold Pulse” section located within “Height Control” ◊

Stage #3: Bloom Push/Coloration – Optimum flower coloration and plant hardening is achieved with 65ºF (18ºC) days

and 50º-55ºF (10º-13ºC) nights. This stage is marked by flower buds beginning to push and color (approximately 50-75 days from planting [depending on season, conditions and variety]).

Nights can be cooled an additional 2-5ºF (1-2ºC) during growth “Stages 2 & 3”. This may be advisable under poor light or no PGR culture. The provision of cooler temperatures will improve plant habit and reduce [or even eliminate] PGR requirements. Be aware that such cooling provisions may also modestly lengthen bench time and slightly increase water retention. Refer to “Negative DIF/Morning COLD PULSE” section for additional details.

Additional Temperature Considerations: Speeding Growth- Provided appropriate light levels (as detailed in “Light” [& PAR] sections), the only way to speed bloom in spring callas is to increase average temperatures. However, warm temperatures will produce taller and softer plants with decreased flower color- especially under low light, early season forcings. It is ultimately better to plant early and “slow down” with cooler temperatures, rather than to plant late and push with heat to “catch up”.

Excessively high daytime temperatures are conducive to the proliferation of both soil borne & aerial diseases (i.e. unvented hoop houses). Avoiding high temperatures will help minimize stress and associated disease pressure.

Pale foliage with chlorotic leaf “checkering” usually indicates excessive heat.

◊ See also “Disease Prevention & Control” section ◊

Slowing Growth & Hardening Plants- Growth begins to arrest at temperatures of ≤50ºF (≤10ºC). This might be useful

when it is necessary to hold and/or delay for a scheduled shipment. Temperatures may be reduced both day and night if conditions permit. However, it’s best to not go below 38-40ºF (3.5-4.5ºC).

Cool nights with clear days will promote stronger and shorter stems with brighter, more saturated colors.



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Spring callas are not very tolerant to brief and light frosts. Foliage will not withstand prolonged freezing temperatures. Bulbs will take some frost but cannot withstand a soil freeze to bulb depth.

Vigorous large-leaved (yellow/orange) varieties- These truly benefit from cooler [and brighter] production conditions as

compared to narrow-leaved (Z. rehmannii hybrid) varieties. Providing these varieties with an altered production environment for “Stages 2 & 3” can result in more compact plants with smaller leaves and higher floral productivity.

◊ See also “Light” and “Fertility & Nutritional Supplements” sections ◊ Humidity and Airflow:

When spring callas are provided relatively high humidities they tend to produce more “lush” and vigorous growth with broader leaves. However, constant overly humid and excessively hot or cold conditions can favor foliar diseases and/or root diseases, especially in the absence of adequate airflow and in low light and/or crowded conditions. Fans hung overhead and in series around the greenhouse generally provide the desired horizontal airflow. Properly engineered, such a system is capable of creating a non-stagnant and uniform climate throughout the crop.

Low relative humidities will act to reduce leaf widths, lessen general vigor and fullness.

WATER MANAGEMENT

Many variables contribute to the rate of water consumption and evapotranspiration. These variables include the water holding capacity of media, stage & rate of crop development and seasonal conditions (i.e. prevailing temperatures, airflow and/or wind, relative humidity, light levels, etc.). Effective irrigation management therefore requires constant monitoring of variables and routine adjustments to achieve best results.

Goals & Methods of Water Management:

The goal is to keep media uniformly moist while avoiding excessively wet and/or dry soil conditions that result in unnecessary stress leading to root injury and increased pathogen susceptibility. Catastrophic problems can stem from alternate extreme dry then extreme wet soil conditions, especially in the presence of slow release fertilizers in warm conditions. Irrigations should be full and thorough while also being appropriately timed based on conditions.

Dry stress can further have negative impacts on flowering (i.e. shorter stems, abortion and/or blindness).

After the initial “wetting” that occurs at planting, the 1st thorough watering should be provided within 2-3 days using GSBG’s

recommended four-part preventative chemical drench (described in the “Disease Prevention and Control” section). Follow with a 2

nd chemical drench at day 14-21. Then water sparingly until leaves unfurl. Thereafter, it is best to maintain good

and uniform moisture levels since rate of evapotranspiration will begin to sharply increase as canopy growth advances.

Leaves remaining wet overnight from irrigations, sprays or rainfall may be subject to foliar pathogens.

Fertilizer applied to leaves in warm and bright conditions may cause phytotoxicity.

Pooling and splashing can easily spread diseases.

◊ See also “Fertility & Nutritional Supplements”, “Disease Prevention & Control” and “Non-Infectious Leaf Damage” ◊

Subirrigation methods such as ebb & flood or capillary mat systems, etc. can easily spread soil borne disease while also posing leaching challenges. Avoid these systems if possible or use with various precautions (i.e. routine disinfection, frequent “top-down” leaching, added airflow and increased scouting for disease).

Water Quality & Sanitation:

Good quality water with a combined E.C. below 1.5 sustains plant quality, growth and overall plant health. High salinity or other water problems should be treated for best results. The addition of Zero Tol at 1:1000 to 1:3000 for algae control is compatible with and recommended for forcing callas as it assists in disease management.

DO NOT combine ZeroTol with metal-based fungicides or supplements due to its strong oxidizing characteristics.

◊ See also “Fertility & Nutritional Supplements” and “Disease Prevention & Control” sections ◊

FERTILITY & NUTRITIONAL SUPPLEMENTS

Proper fertility is critical to achieving full plant growth with well-colored leaves and optimal flower productivity. Surprisingly, Callafornia Callas don’t require nor benefit from high constant fertility. Plants however do benefit from additional calcium supply, which assists in strengthening cell walls of leaves and flowers, plus improves disease resistance. Providing excessive nutrition, especially nitrogen, can lead to undesirably “lush” growth and limited floral potential paired with increased PGR requirements.

It is best to avoid ammonia forms of nitrogen since it is linked to increased erwinia pressure. Keep media moist with E.C. levels initially between 1.5-2.0, then reducing to 1-1.2 once canopy has developed. Avoid E.C. levels above 2.5; noting that high salts with periods of dryness leads to root damage. Keep climate, growth and fertility records for future reference.

Pre-plant Fertilizer “Charge”:

A preplant charge of nitrogen and potassium (containing little or no phosphorous) should be incorporated into the media. This will produce good early establishment of roots and improved early vigor. The ideal starter “precharge” would be a 10-20 day soil incorporated application of N-P-K at approximately a 15-3-15 analysis, plus minors.



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Liquid Fertility:

Excellent crop quality can generally be achieved using 20-10-20 [+ minors] plus occasional Calcium Nitrate [+ minors]. Some prefer to alternate Calcium & Potassium forms of Nitrate [+minors] for very good results. Either method, is best employed with constant 100-150ppm [weekly] feed using a semi-balanced formulation when conditions where light levels are good enough to allow for weekly irrigations. However, increase ppm when weekly irrigations are not possible during early growth & development (i.e. low light and/or low transpiration conditions):

Alternate 1- use 200ppm if biweekly irrigation is possible Alternate 2- use 300ppm if less frequent irrigation is possible

Thereafter, it is preferred to reduce fertility concentration to 75-100ppm accordingly as plants begin to foliate and dry down more quickly through active evapotranspiration.

Reducing nitrogen ppm in later growth stages enhances floral productivity; ideal timing is dependent on genetic group.

Depth and volume of large containers extend availability of fertilizer once lower N ppm transition is

executed; adapt accordingly (transition earlier; leach; etc.). ◊ See also “Genetic Groups & Fine Tuning Performance” section ◊

Periodically leach once canopy develops. Leach at a ratio of 3-4 fertilizer : 1 water for larger pots and 2:1 for smaller pots to avoid salt edge burn.

◊ See also “Slow Release Fertilizers” and “Non-Infectious Leaf Damage” sections ◊

Low phosphorous fertilizers (i.e. 17-5-17) often result in better plant balance with small pots

and/or vigorous large-leaved (yellow/orange) varieties.

Slow Release Fertilizers:

Supplying no more than 40-50% of your target fertility with a slow release will allow for necessary leaching and supplemental fertigation as desired. Charges greater than 30 days tend to cause marginal salt burn when temperatures rise to above 78ºF (25°C) and/or when media is allowed to dry excessively. Fertility release begins at time of media incorporation; use media promptly to avoid high salt conditions at planting.

Uniform incorporation of slow release or other granular fertilizers can be difficult without a commercial mixing line. Adding it at end of mixing process will prevent accelerated release. Pots may be treated individually with a measured “top-dress”.

Supplemental Fertility: Incorporating 3 lbs. each of lime and dolomite per cubic yard (1.78 kilos/ cubic meter) can provide calcium for improved plant quality and disease resistance.

Pale foliage color can be corrected or even prevented with sequestered iron chelate at a rate of 6oz/100 gal (46.9 mls/ 100 L) [using a 13.2% formulation]. Introduce iron chelate with your liquid feed and apply weekly once the leaves unfurl.

The use of paclobutrazol paired with cooler forcing temperatures will also aid in darkening foliage.

Potassium silicate can offer numerous benefits in plant performance. plants demonstrated greater disease resistance through immune supportive benefits known as SAR (systemic acquired resistance) in our trials with Pro-Tekt @ 50-100ppm using 8.5-17oz/100 gal (67-134ml/100L) constant feed. Silicates are also correlated with stronger stems and tougher leaves that tend more resistant to foliar pathogens and pest feeding. Gem/Rehmannii type spring callas yielded longer & stronger stems with larger heads when treated with this material. Intermittent sprays @ 100ppm also reported to be an effective means of application and uptake. Results may vary; we recommend that you trial for your site and conditions.

Potassium Silicates are available under other trade names such as SiloTec, SilMatrix, PotSil, etc.

Modified Fertility:

Large-leaved varieties (i.e. yellow/orange genetic groupings) benefit from a “modified fertilizer” regime that employs reduced Nitrogen (N) concentrations while increasing Phosphorous (P). This allows for greater light penetration into the canopy and crown for flower induction & development while simultaneously improving plant habit.

Recommended ratios can be found in preformulations such as Peter’s 10-30-20 “Hi Bloom” + minors. The target range would provide 50ppm N - 150ppm P - 100ppm K, as opposed to the ppm levels derived from 20-10-20 (i.e. 100-50-100).

Best results are experienced when the switch to “modified feed” commences at the time of paclobutrazol treatment (somewhere between “early” and “late sprouting”). Thereafter, this fertility should continue through flowering.

Large-leaved varieties produced using “modified fertility” tend to be more compact with smaller overall leaves, plus

benefit from modest-to-significant increases in flower counts.



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HEIGHT CONTROL

Spacing, Light & Fertility:

Numerous variables can separately or together affect growth habit such as light; temperature; fertility & water management; relative humidity; morning “cold pulsing” and/or far red light. Appropriately timed crop spacing and optimizing cultural inputs can help to minimize PGR (plant growth regulator) requirements.

Broad-leaved [yellow/orange] varieties benefit from higher light, lower nitrogen levels and early, additional spacing.

Negative DIF / Morning “Cold Pulse”:

Potted spring callas generally benefit from production conditions where they experience a sharp “diurnal” morning drop in temperature. Providing a “cold pulse” to greenhouse or cold frame environment during the early morning hours can greatly improve compactness of plant habit and body. This is best applied shortly after “Stage 1” [germination / PGR application] and can significantly reduce PGR requirements.

The “cold pulse” is specifically achieved by providing a “DIP” or sharp reduction of 10ºF (5.5ºC) below target night temperatures. For example, 58ºF (14.5°C) night with a morning DIP to 48ºF (9°C) beginning at predawn to sunrise and continued for 3-4 hours. Forcing times should not be appreciably impacted since overall average temperatures can be adjusted to compensate. Multiple plantings will however necessitate separate greenhouse zoning to accommodate the different temperature recommendations specific to “Stages 1, 2 & 3” (as described in the “Growth & Development” section).

Use of a germination chamber for “Stage 1” allows for better isolation from DIF provisions during subsequent “Stages”.

Variety Selection for Pot/Container Use:

GSBG’s Callafornia Calla varieties have been categorized into five separate uses [4 pot/container “sizes” & 1 cut-flower use]:- extra small, small, medium, large & cut (abbreviated as “XS”, ”SM”, ”MD”, “LG” and ”CUT”). Additionally, GSBG’s varieties have been categorized by relative stem heights: short, medium, tall & extra tall (abbreviated as “S”, “M”, “T”, “XT”). This detailed information can be found in GSBG’s “Master Planning Document” (available from your broker or download from UwwwU.goldenstatebulb.com / UwwwU.callaforniacallas.com).

Genetic Groups & Fine Tuning Performance:

GSBG’s Callafornia Calla varieties can be categorized into three general leaf types: narrow, hybrid and broad. Each of these types has distinctive characteristics relative to their natural height tendencies and natural floral productivity. Recognizing that each group has its strengths and shortcomings, growers can sharply improve upon performance through modest cultural adaptations that have proven to deliver desired corrections for successful results. Table 4 offers a general perspective relative to [natural] flower stem length and floral productivity characteristics.

TABLE 4: GENETIC GROUPS and NATURAL PERFORMANCE CHARACTERISTICS

GENETIC GROUP Leaf Description Natural Stem Height Natural Floral Productivity

Narrow Leaf Long & skinny Short-Medium High-Good

Hybrid Leaf Medium & Ovate Medium-Tall Good-Fair

Broad Leaf Arrow Head Tall-Extra Tall Fair-Limited

◊ Various cultural adaptations can influence natural tendencies of these genetic groups to bring desired results ◊

The most productive varieties tend to produce the shortest stems, while those that are naturally quite tall tend to produce relatively few stems. By modifying cultural inputs, growers can coax the short to be rather tall. And through a differing set of treatments, growers can advance productivity in those that tend to yield inadequate results. Proposed adaptive cultural techniques fall into three general categories: light, temperature and fertility. Table 5 offers some immediate insights relative to suggested cultural adaptations per genetic group; more specific details are can be found throughout the balance of this document.

◊ See also “Light”, “Temperature” and “Fertility & Nutritional Supplements” sections ◊

TABLE 5: GENETIC GROUPS and RECOMMENDED CULTURAL ADAPTATIONS

GENETIC GROUP Shading Requirement Temperature Aggressive Fertility Phase

Narrow Leaf Early- until “mid” canopy Relatively Warm until canopy development

Hybrid Leaf Mid- until leaf unfurl Intermediate until leaf unfurling

Broad Leaf None- only to moderate temp. Relatively Cool until “late” sprouting

◊ See “Light”, “Temperature” and “Fertility & Nutritional Supplements” sections for specific details ◊

PGRs (Plant Growth Regulators):

Paclobutrazol, sold under various tradenames (i.e. Bonzi, Paczol, Piccolo, etc.) is presently the most effective and widely used growth regulator for spring callas. It dramatically improves the potted plant habit of spring callas by reducing foliage height, darkening leaves, toning plants and has been recognized to improve shipping and postharvest quality.

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Plants must be actively growing for paclobutrazol to be taken up by the roots and assimilated. Cold dark conditions immediately post application will greatly reduce PGR effectiveness. Keep your environment stable and within the recommended temperatures for consistent and replicable results. A “cold pulse”/”Morning DIP” can however greatly improve PGR effects. Additionally, the provision of slightly cooler temperatures, high quality greenhouse coverings and/or supplemental lighting during production “Stages 2 & 3” can also improve PGR results.

PGR Rate & Application Number:

Our recommended drench rate range varies between 8-25ppm with the provision to deliver between 1-3 separate applications. Repeat applications at lower concentrations (8-15 ppm) generally yields superior results compared to single (or fewer) applications of higher concentrations. Though higher rates may possibly reduce later flower numbers, they are often favored when shipping over longer distances.

PGR rates should be adjusted up or down depending on numerous variables including: pot/container size; media components; fertility regime; planting season; spacing provisions; PGR timing & number of applications; bulb size; temperature/”DIF” conditions; shipping duration/conditions; merchandising light levels; etc.

Various organic media components widely used in the eastern USA have proven to significantly reduce paclobutrazol

efficacy (i.e. composted/uncomposted pine bark). Avoid these types of media components or adjust rates accordingly.

GSBG’s Callafornia Calla varieties have been categorized into four separate PGR use classifications- “x-low”, ”low”, ”medium” and ”high”. This detailed information can be found in GSBG’s “Master Planning Document” (available from your broker or download from UwwwU.goldenstatebulb.com / UwwwU.callaforniacallas.com). Refer to Table 6 for rates associated

per corresponding varietal class.

TABLE 6: PACLOBUTRAZOL APPLICATION # & RATE by VARIETAL CLASS

VARIETAL CLASS Application # Rate Dilution

X-LOW to LOW 1-2x @ 8-10ppm 25.6-32oz/100 gal (200-250/100 L)

MEDIUM 1-3x @ 10-15ppm 32-48oz/100 gal (250-375ml/100 L)

HIGH 2-3x @ 15-25ppm 48-80oz/100 gal (375-625ml/100 L)

◊ Rates based on moderate-good California light levels; local conditions may require rate adjustments ◊

Callafornia Calla bulbs are shipped from October through the following September, which leads to differing sprout length at the time of supply. Early season bulbs are “fresh” with a minimum or relatively short amount of dormancy prior planting. These bulbs have no-to-limited sprout development and will be grown into progressively shorter days [in the Northern Hemisphere]. Conversely, bulbs supplied mid-late season will arrive with obvious-to-significant sprout development and will grow in relatively long-days. These sprouting and light quality factors should be taken into consideration when determining appropriate PGR rate and application number. Refer Table 7 for proposed PGR demands relative to planting season and sprout development.

TABLE 7: PLANT SEASON & SPROUTING vs. GENERAL PACLOBUTRAZOL DEMANDS

PLANTING SEASON Plant Months Bulb Sprout (receiving) General PGR Demands

EARLY Oct-Dec None-0.25” (0.63cm) High

MID Jan-Mar ~0.25-0.5” (0.63-1.25cm) High-Med

LATE Apr-Jun ~0.5-0.75” (1.25-1.9cm) Med-Low

X-LATE Jul-Sept ~0.75” (1.9cm) Low-Med (depends on light levels)

◊ Bulb Sprout measured from surface of bulb; see Table 6 for Sprout Development details by relative pot size ◊

Paclobutrazol rates higher than 30ppm may arrest plant height completely, particularly with more compact varieties.

Such rates should be evaluated under adverse conditions (i.e. dark/crowded/warm greenhouse environment).

PGR “overdose” causes leaf-wrinkling, rosetting, stunting, reduced flower counts and/or increased bench time. In such instances, a “GA Rescue” spray can be helpful @ 25-50ppm GA3 or GA4+7 & BA6 [plus surfactant].

PGR Drench Timing & Volume:

Pots must be uniformly moist prior to paclobutrazol drench application. It is therefore best to apply PGR 1-2 days after irrigation; this often closely coincides with the 2

nd fungicide drench. Segregating pots by sprout size to treat the tallest pots

first brings the most uniform results. Then, when slower pots reach desired developmental stage, those pots may also receive their 1

st PGR application. Second and subsequent PGR applications should be made 6-10 days after the previous;

the general practice operates on 1-week intervals.

PGR application to dry media will cause “shock” and results in stunted plants.

PGRs applied beyond 40 days post emergence can result in shorter/fewer flowers.

Earlier PGR application = Greater response!


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Different pot sizes create unique height objectives relative to achieving aesthetic balance. Early PGR application therefore becomes increasingly more critical the smaller the pot becomes. Conversely, timing is often slightly delayed for larger pot sizes. Since paclobutrazol is a both a powerful and persistent PGR in soil, each pot/container size must also be treated with a rather precise volume of solution. Refer to Table 8 for specific details relative to each pot/container size.

DO NOT apply PGR drench in excess volume; precise amounts are required.

TABLE 8: PACLOBUTRAZOL DRENCH VOLUME & TIMING by POT/CONTAINER SIZE

POT SIZE (diameter) PGR Volume per Pot PGR Timing Sprout Development

3-3.5” (7.5-9cm) 2oz (59ml) Very Early None or just barely visible

4-5” (10-13cm) 4oz (118ml) Early 0.25-0.5” (0.63-1.25cm)

6” (15cm) 6oz (177ml) Early-Mid 0.5-1.5” (1.25-3.8cm)

8” (20cm) 10oz (296ml) Mid 1-3” (2.5-7.6cm)

10-12” (25-30cm) 12-14oz (355-414ml) Late 2-4” (5.1-10.2cm)

quart (10-13cm) 4oz (118ml) Early-Mid 0.5-1.5” (1.25-3.8cm)

gallon (17cm) 8oz (237ml) Mid 1-3” (2.5-7.6cm)

2 gallon (25-30cm) 12-14oz (355-414ml) Late 2-4” (5.1-10.2cm)

◊ Sprout Development measured from surface of soil ◊

No matter the pot/bulb configuration, it is BEST TO PURSUE EARLIER APPLICATION ON AGGRESSIVE VARIETIES SUCH AS THE YELLOW & ORANGE GROUPS. Thus, consider treating when sprouts are no longer than 0.25-0.5” (0.63-1.25cm) above the soil; shorter [or not even visible] is better. See Table 9 for details.

TABLE 9: PACLOBUTRAZOL DRENCH TIMING RELATIVE TO GENETIC GROUP

GENETIC GROUP Leaf Description PGR Timing Sprout Development

Narrow Leaf long & skinny Early-Mid Short/medium: varies by pot size

Hybrid Leaf medium & ovate Early-Mid Short/medium: varies by pot size

Broad Leaf arrow head Very Early None/x-short: none or just barely visible

◊ See Table 6 for recommended Sprout Development details by relative to each pot/container size ◊

PGR Delivery Method(s): The volume of solution delivered per pot is far more critical than a slight variation from the desired rate (ppm). This is due to the fact that paclobutrazol is "trapped" in the media when excess PGR solution is applied or even when supplied past “runoff”(i.e. double solution volume = double dosage). Thus, careful measurement/dilution paired with delivery through an accurate metered/dosing system is strongly advised.

Prepare diluted solution at desired PGR rate (ppm) then use one of the following reliably accurate delivery methods:

Method A: Dosing or metering systems such as a Dramm Chemdose™ or a Chemical Container Eze-Dose™

allow for precise delivery at the desired rate of PGR [from a pre-diluted, ready-to-apply solution]. Less expensive alternatives are now also available such as the “Bonzi Dose Stick” (available through Brinkman in North America).

Method B: In the absence of specialized “dosing” equipment, using an “agitated spray tank method" can also be

very effective. General steps are as follows: 1. Remove nozzle tip from spray wand. 2. Reduce pressure at regulator to soften force of fluid (start with 7-10psi (0.4-0.7bars); adjust accordingly). 3. Test fill a series of measuring cups to determine the required “trigger pull" duration. 4. Proceed with “rhythm” timing for rather accurate dosing.

AVOID USING INJECTORS to apply PGRs. They work best for delivering fertilizer and/or fungicides where deviations from desired rate are tolerable. Injectors are prone to deviate or “drift” from the setting shown (i.e., 1:200), especially with age and scoring. While being easily tested with an EC meter, they require more regular maintenance and calibration for successful "injection" of PGRs. Moreover, without the use of an integrated blending tank, varying rates of material will be delivered from one pot to the next, as injectors pull & release “pulses” of solution from the concentrate tank.

These recommendations have been tested at Golden State Bulb Growers on California’s central coast. Since the

effective use of PGRs is an art and science, growers should conduct their own trials specific to rates; timing; multiple applications; bulb form & size; pot/container size; media type; environmental differences; etc. Include untreated controls.

◊ Please contact us for additional guidance regarding your specific environmental conditions and goals ◊



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DISEASE PREVENTION & CONTROL

Soil Borne Disease Overview:

Achieving and maintaining quality Callafornia Callas for the entire length of the crop requires careful attention to details, supported by cultural practices that focus on the prevention and control of diseases.

Golden State Bulb Growers’ Callafornia Calla bulbs are field grown to the highest standards. Bulbs are inspected by hand to meet benchmarks for form, size & overall quality. Bulbs are also pretreated with a proprietary synergistic solution [just prior to shipping] as the first step to soil borne disease prevention.

Diseases are difficult to control once established. Throughout growth and development care should be taken to avoid “stress-induced disease”. Conditions prone to stress the crop include extremes of “soggy” media; drought (even when brief); high salts; and/or dry wind. Following optimal cultural inputs will maintain a healthy crop, performing at its best.

During early forcings, most spring calla diseases are favored by overly wet and cold conditions. In summer forcings, disease(s) are favored by overly wet and/or dry conditions paired with warm days/nights.

Spring callas can be infected by three (3) primary soil borne pathogens that independently, or in concert, can cause root and bulb rot. These pathogens include fungi: Pythium & Phytophthora (“water molds”) plus Rhizoctonia and bacteria: Erwinia (Pectobacteria spp.). “Water molds” are often the first and most critical component in the disease complex, followed by Rhizoctonia. Though sometimes independent, Erwinia predominantly manifests as a secondary infection after root injury.

Pesticide Drench Components:

Only controlling a portion of this pathogen complex can lead to the worsening of any other untreated pathogens. Control and prevention of these diseases therefore requires a “cocktail” since none of these products can successfully address these pathogens alone. Conducting extensive research on the efficacy of fungicidal/bactericidal drenches, GSBG has concluded the results of their use, combinations and alternatives. Our best tank mixed, four-part

chemical drench is a synergistic combination targeting the “3-pathogen complex” utilizing the following preferred materials:

1) WATER MOLD part 1: Subdue Maxx (mefenoxam 25.1% ai)

2) WATER MOLD part 2: Aliette (fosetyl-aluminum 80% ai)

3) RHIZOCTONIA [plus WATER MOLD part 3]: Heritage (azoxystrobin 50% ai)

4) ERWINIA: Agrimycin-17 (streptomycin sulfate 21.2% ai) ◊ See Table 10 for additional product details, rates and alternate options ◊

4-PART TANK MIX*



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TABLE 10: THREE PATHOGEN “FOUR-PART Cocktail Drench” RECOMMENDATIONS

PATHOGEN GROUP & MATERIAL DILUTION RATES

(1) WATER MOLDS Subdue Maxx (mefenoxam 25.1% ai) liquid

Aliette (fosetyl-aluminum 80% ai) dry Segway/Ranman (cyazofamid 53.45% ai) liquid Terrazole (etridiazole 35% ai) dry

(2) RHIZOCTONIA Heritage (azoxystrobin 50% ai) dry [also Pythium control]

Pageant (pyraclostrobin 12.8% & boscalid 25.2% ai) dry Prostar (flutolanil 70% ai) dry Medallion (fludioxonil 50% ai) dry

Compass (trifloxystrobin 50% ai) dry 3336 Clearys (thiophanate methyl 46.2% ai) liquid 26019 Chipco (iprodione 50% ai) dry

(3) ERWINIA Agrimycin-17 (streptomycin sulfate 21.2% ai) dry

Phyton-27 (copper sulfate pentahydrate 21.4% ai) liquid

0.5-1oz/100 gal (4-8ml/100 L)

13oz/100 gal (98gm/100 L) 2-6oz/100 gal (15.5-47ml/100 L) 4-6oz/100 gal (30-45gm/100 L)

0.9oz/100 gal (6.7gm/100 L)

12-18oz/100 gal (90-135gm/100 L) 3-6oz/100 gal (22.5-45gm/100 L)

2oz/100 gal (15gm/100 L) 1-2oz/100 gal (7.5-15gm100 L)

20oz/100 gal (156ml/100 L) 6.5 oz/100 gal (49gm/100 L)

8-16oz/100 gal (60-120gm/100 L)

13-20oz/100 gal (102-156ml/100 L)

= Primary FOUR-PART Tank Mix components integrated for optimal synergies

= Alternate FOUR-PART Tank Mix newer chemistry components (trial for your own conditions)

Aliette can occasionally be phytotoxic to foliage when combined with Phyton-27. Use caution accordingly. Segway/Ranman and Pageant are very effective new chemicals. Trial in your conditions for best results. These materials are very effective against targeted pathogens. We have however observed some delay (3-

6 days) in early growth with Terrazole and to a lesser extent in Medallion [under sub-optimal conditions]. Based on this, we have downgraded these two materials from our preferred drench recommendations.

◊ Rates designated as ounces/100 gallons (mls or gms/100 liters) ◊

Erwinia, also known as “stinking soft rot”, is best controlled with Agrimycin-17 (streptomycin sulfate 21.2% ai). Alternatives for bacterial control are few. GSBG's preconditioning treatment includes a fixed copper provided on your bulbs at the time of supply. However, fixed coppers are root phytotoxic when applied as a drench (suitable ONLY for spray application). When seeking alternative controls for Erwinia pressure, consider another agricultural antibiotic [at label rates] or soluble copper Phyton-27 (copper sulfate pentahydrate 21.4% ai).

◊ See Table 10 for material and rate details ◊ The materials described above in Table 10 have been found superior by Golden State Bulb Growers for the labels registered in California. PRODUCT REGISTRATIONS, LABELING AND AVAILABILITY VARY BY LOCALE; thus, some of these materials may not be available in your region. IF ANY OF THESE PRODUCTS ARE NOT AVAILABLE IN YOUR LOCALE, THEN ADDRESS THE THREE MAJOR PATHOGENS COMPREHENSIVELY WITH THE BEST PRODUCTS AVAILABLE. Please consult your local information or farm/grower extension agency for usages or alternatives. Callafornia Callas tend to be tolerant of most products. Before treating your crop with new products or combinations, we encourage trialing and experimentation that includes controls plus thorough record keeping.

Pesticide Drench Timing:

The timing of these “cocktail” drenches is critical to the success of your crop. The 1st drench should occur within the first 2

to 3 days of initial watering. Timing of the 2nd

drench should be made when leaves unfurl (generally @ week 4-2 [early vs. late season]). A 3

rd drench may be necessary when crop enters into [flower] budding stage (generally @ week 12-7 [early

vs. late season]). The 3rd

and final drench is required only if weekly root inspections reveal cleared/browning roots, uneven growth, diseased plants and/or if poor, prolonged shipping durations/conditions are anticipated.

Always drench in the mornings or early enough for all foliage/runoff to dry thoroughly.

Biological & Alternative Approaches:

As a supplement to chemical controls or where chemicals cannot be used, please consider the use of biological, organic and/or “green” options that may be available.

Media incorporation with beneficial biological organisms like Trichoderma can be useful. These organisms are found in products like RootShield or SoilGuard (Gliocladium [related to Trichoderma]). Either can be applied at a rate of 1lb/yd

3

(593gm/m3). Each is compatible with most fungicides and can help maintain healthy roots. Although somewhat less

effective than incorporation, these biologicals can also be drenched at planting @ 8oz/100 gal (60gm/100 L) and repeated during growth (day 21-28) & development (day 42) to thoroughly colonize the root system.



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New biologicals are being continually registered and should be trialed both with and without fungicide drenches prior to large-scale application.

The use of ZeroTol (hydrogen dioxide 27% ai) @ 1:1000 to 1:3000 using 49-148oz/100 gal (383-1156ml/100 L) is often used for control of algae growth as a constant supply in irrigation water. This rate has also been recognized to aid in the management of the three-pathogen complex (1º- pythium/phytophthora & rhizoctonia and 2º- erwinia).

DO NOT combine ZeroTol with metal-based fungicides or supplements due to its strong oxidizing characteristics.

When preferred materials are available, alternative materials should not be considered an intended substitute for

preventative fungicide drenches. They can however help extend intervals between drenches. ◊ See also “Fertility & Nutritional Supplements” section for benefits of using Potassium Silicates ◊

Foliar Disease Overview:

Spring Callas can be subject to an array of fungal and bacterial leaf spots. These can often be difficult to accurately interpret without sampling for laboratory diagnosis. Depending on your conditions and anticipated disease pressure, leaf spot may be addressed preventatively, if possible, or controlled as necessary. Once an infection is observed, it is best to control with a fungal/bacterial tank mix combination spray since initial infections often lead to secondary infections.

Removal of infected plants and/or leaves is recommended.

Pesticide Spray Components: Watch for leaf spot as leaves unfurl. Once leaf spot is observed, spray foliage to “runoff” with a selection and/or 3-Part

Combination of the following:

1) BACTERIAL LEAF SPOT part 1: Champ II (copper hydroxide 37.5%)

2) BACTERIAL LEAF SPOT part 2: Dithane (mancozeb 75%)

3) FUNGAL LEAF SPOT option 1: Pageant (pyraclostrobin 12.8% & boscalid 25.2% ai) option 2: Daconil Weather Stik (chlorothalonil @ 54%) option 3: Chipco 26019 26GT (iprodione @ 23.3%)

Do a tank mix of above if both bacterial and fungal leaf spots are present. Watch for residues at the higher rates.

Always spray in the morning or early enough to allow the materials to thoroughly dry.

Prolonged activity of spray solution may lead to phytotoxicity.

◊ See Table 11 for detailed recommendations, rates and alternatives ◊

TABLE 11: LEAF SPOT “Cocktail Spray” RECOMMENDATIONS

PATHOGEN GROUP & MATERIAL DILUTION RATES

(1) BACTERIAL LEAF SPOT Champ II (copper hydroxide 37.5% ai) liquid Dithane (mancozeb 75% ai) dry

Phyton-27 (copper sulfate pentahydrate 21.4% ai) dry

(2) FUNGAL LEAF SPOT Pageant (pyraclostrobin 12.8% & boscalid 25.2% ai) dry

Daconil Weather Stik (chlorothalonil @ 54% ai) liquid Chipco 26019 26GT (iprodione @ 23.3% ai) dry Heritage (azoxystrobin 50% ai) dry Medallion (fludioxonil 50% ai) dry Compass (trifloxystrobin 50% ai) dry

32-64oz/100 gal (250-500ml/100 L)

32oz/100 gal (240gm/100 L) 1-5oz/100 gal (7.5-37.5gm/100 L)

4-18oz/100 gal (30-135gm/100 L)

22oz/100 gal (171ml/100 L) 32oz/100 gal (240gm/100 L)

4-8oz/100 gal (30-60gm/100 L) 2-4oz/100 gal (15-30gm/100 L) 2-4oz/100 gal (15-30gm/100 L)

= Primary Tank Mix components Though very effective, these materials are prone to significant residues due to high rate requirements. Alternate materials listed have shown good efficacy while yielding in little-to-no residues. Consider these

newer chemistry materials as viable curatives, particularly when product is close to finish and/or shipping. ***** INCLUDE SURFACTANT AS REQUIRED ****


DO NOT COMBINE FOLIAR COPPERS WITH ALIETTE OR OTHER ACIDIFYING PRODUCTS OR WHERE WATER SOURCES HAVE A PH THAT TENDS OR MOVES BELOW 7.0 (NEUTRAL). Test solution pH before spraying anything that may be in question.

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Non-Infectious Leaf Damage: Leaf Spot Phytotoxicity- Be aware that occasional leaf spot phyto can occur when using overhead irrigation on

bright, warm days. This tends to occur with liquid fertigations or using chemical drenches/sprays late in the evening where leaves remain wet overnight. Care should be taken to irrigate early and avoid wetting foliage in high light outdoor conditions. Pesticide sprays should also be scheduled early in the day to allow for foliage to dry prior to nightfall.

Edema- Leaf-tip “clearing” or “glassy” [aka. vidrio] tissue may sometimes be observed at sprout emergence. Often

referred to as edema or oedema, it does not turn “corky” but instead causes malformed sprouts and/or leaf tips. Damaged tissue will turn pale green and remain somewhat distorted due to failure of cells to expand normally. In severe cases it will turn yellow or even necrotic. Left unchecked, this can lead to continued foliar breakdown and secondary infection.

It is caused by warm and very moist soil conditions paired with dark, cool and high humidity conditions that lead to low evapotranspiration and exceptionally high turgor pressures. Rupturing of cell walls immediately results in “clear” or “glassy” tissue.

Adjust conditions by using appropriately porous media, watering early in the morning and only as needed, increasing light levels, avoiding crowded conditions, purging humidity and increasing airflow across the crop. Once edema is observed, preventatively treat to suppress potential entry of secondary infections with a fungicidal/bactericidal spray until [edema] ceases to advance.

◊ See also “Foliar Disease” section ◊

Guttation- Leaf-tip water droplets can sometimes result in small necrotic spots due to salt concentrations

accumulating along leaf tips and/or margins. This can occur during times of high turgor pressures; overly dried media with excessive fertilizer release with temperature-dependent slow release fertilizers; and/or a lack of clear water leachings. Weakened and/or necrotic tissue is easily subject to secondary infections. Leaching practices can reduce or even prevent “salty” guttation damage.

◊ See also “Water Management”, “Slow Release Fertilizer” and “Foliar Disease” sections ◊

Leaf Sheath Decline- Spring callas may sometimes exhibit sheath decline or “dirty socks” (a sheath is the stubby

leaf-like appendage found below 1st leaf). The sheath tip will generally turn yellow and advance to encompass most of

it. These will often proceed to desiccate, though absent any “black” necrosis. An examination of roots is advised whenever “dirty socks” are observed.

Often perplexing growers, the cause of damage is due to significant dry and/or salt stress presented at any stage of development. Continuing stress will cause root damage and collapse that will lead to additional leaves exhibiting mottled chlorosis. Leach salts regularly and avoid excessive drying.

◊ See also “Water Management” and “Disease Prevention & Control” sections ◊

Inspect Crop Weekly:

Routinely scout for cleared or browning roots, leaf spots, etc. Be sure to re-drench per recommendations if root problems are discovered. These chemicals will lose their effectiveness over time. The same is true of organisms like Trichoderma, which needs to establish well through colonization. For this reason, repeat drench with Trichoderma at day 21-28 and again near day 42, if necessary.

ALWAYS WATCH FOR ERWINIA INFECTED PLANTS TO CAREFULLY ROGUE & DISCARD. Sanitation is critical, especially in multiple cropping programs where rot can progress without an obvious cause. Between crops make it a practice to sanitize benches, floors, conveyors, pots/containers, soil mixers, etc.

◊ See also “Disease Prevention & Control” and “Insects” sections ◊

INSECTS

Control of Fungus Gnats and Shoreflies is important due to their ability to spread bacteria and other diseases. These

pests can often reside under greenhouse benches, especially when media residues accumulate and run-off does not drain away adequately. Such conditions tend to develop moss and algae that can be a haven for these pests. Removing surplus media residues, improving facility drainage, and/or applying a hydrated lime slurry can sharply reduce localized pest pressure. Treat with appropriate insecticide before population/damage expands.

Whenever possible control white flies, aphids and thrips on an as-needed basis. Both thrips and aphids are capable of

rapidly causing leaf and flower damage. Furthermore, both thrips and aphids are also capable of potentially spreading foliar viruses. Aggressive control measures should therefore be used to quickly control outbreaks in population development once observed.

Also watch for early leaf chewing evidence from larvae after sprouting. Observation requires an immediate treatment to

prevent significant damage from occurring.



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Insecticidal Spray Components: Scout and monitor for insect pests on a regular basis. Once pressure is observed, rotationally spray and/or drench

with a selection of materials that are both locally available and have historically provided adequate suppression and control. Though most growers have a preferred array of insecticides relative to horticulturally important pests, a sample listing of rather effective materials and rates can be found in Table 12.

TABLE 12: SAMPLE INSECTICIDE REFERENCE LIST

MATERIAL PESTS DILUTION RATES

Abamectin (abamectin 2% ai) liquid Conserve (spinosad 11.6% ai) liquid Diazinon (diazinon 48% ai) liquid Dursban (chlorpyrifos 50% ai) dry Endeavor (pymetrozine 50% ai) dry Evergreen (pyrethrins 6% ai) liquid ImidiPro (imidacloprid 21.4% ai) dry Malathion (malathion 56.8% ai) liquid Mavrik (tau-fluvalinate 22.3% ai) liquid Mesurol 75-W (methiocarb 75% ai) dry Orthene (acephate 75% ai) dry Overture (pyridalyl 35% ai) dry Pylon (chlorfenapyr 21.4% ai) liquid Tempo (cyfluthrin 20% ai) dry

Aphid, Thrip, Whitefly Shore Fly, Thrip, Lepid. Larvae Aphid, Thrip, Whitefly Aphid, Thrip, Whitefly Aphid, Whitefly *synergist/exciter (piperonyl butoxide) Aphid, Thrip, Whitefly Aphid, Thrip, Whitefly Aphid, Thrip, Whitefly, Lepid. Larvae Aphid, Thrip Aphid, Thrip, Whitefly Thrip, Lepidoptera Larvae Fungus Gnat, Thrip, Lepid. Larvae Fungus Gnat, Shore Fly

8oz/100 gal (63ml/100 L) 6-11oz/100 gal (47-86ml/100 L)

16oz/100 gal (125ml/100 L) 8-16oz/100 gal (60-120gm/100 L)

2.5-5oz/100 gal (19-37.5gm/100 L) 1-4oz/100 gal (8-31ml/100 L)

1.5-3.4oz/100 gal (11.5-25.5gm/100 L) 24oz/100 gal (187.5ml/100 L)

4-10oz/100 gal (31-78ml/100 L) 8-16oz/100 gal (60-120gm/100 L)

5.3-10.5oz/100 gal (39.5-78.5gm/100 L) 8oz/100 gal (60gm/100 L)

5-6oz/100 gal (39-47ml/100 L) 6.7oz/100 gal (50gm/100 L)

Consider Tank Mixing with a synergist/exciter (i.e. Evergreen which contains piperonyl butoxide)

***** INCLUDE SURFACTANT AS REQUIRED **** ***** ENSURE MIXTURE IS AGITATED REGULARLY ****


Callafornia Callas don’t generally exhibit phytotoxic responses to treatment with most insecticides. Most materials can safely be applied at label rates; beware of chemical incompatibilities described on label(s). Always inquire with local agricultural advisors if in doubt.

MARKETING STAGE & POSTHARVEST

Marketing Stage for POTS:

Callafornia Callas tend to produce a “flush” of flowers followed by production of some additional blooms in gradual succession. Plants can be selected to ship when several flowers are colored & open with other buds in various stages of development. Old or blemished flowers should be removed at the time of shipping by “pulling stem” with a sharp, quick tug (note: plants must have adequate moisture and turgor levels for best results). Provided conditions are good, and if desired, plants can be flexibly shipped from the same planting over a few weeks. This period can be enhanced with a simple postharvest treatment as detailed below.

Postharvest Enhancement Spray: Newly Discovered Shelf Life Enhancement: Flowers may now be kept fresh and upright for extended periods after

treatment with an inexpensive PGR spray using either GA3 (i.e. Progib/Falgro) or the combination of GA4+7 & BA6 (i.e. Fascination/Fresco).

Narrow-leaved Z. rhemannii type hybrid flowers often begin to “nod” as individual blooms age past pollen shed, and to a lesser extent, all varieties respond this way. Now it is possible to prevent this response!

Treatment just days prior to shipping can significantly improve postharvest life, sell through and consumer satisfaction.

Postharvest Treatment Methods, Rates & Timing:

Option A: Make only 1 spray “to wet” treatment for good results using 25ppm GA [+ surfactant]. This is done

when “flush” of buds is visible on the majority of crop (pushing up through canopy and beginning to “crack color” [approximately 1-3” (~2.5-7.6cm) from soil surface]). Effects as follows:

1. NO “nod” on old flowers 2. pigment or “purity” of flower color is extended 3. larger cups & heavier stems



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Option B: Apply 2 sequential spray “to wet” treatments for even better results. Make 1st

spray treatment @

10ppm GA [+ surfactant] when the very 1st buds are visible in 5% of the crop. Make 2nd treatment @ 20ppm GA [+ surfactant] when flush of buds are visible on the majority of crop (pushing up through canopy and beginning to “crack color” [approximately 1-3” (~2.5-7.6cm) from soil surface]). Effects as follows:

1. NO “nod” on old flowers 2. pigment or “purity” of flower color is extended 3. even larger cups & stems 4. more blooms at once 5. more uniform stem length

Reduce target GA rate/ppm by 50% in conditions of high heat and/or high humidity to prevent excessive

stretch from occurring in all [Option A/B] instances.

Additional Postharvest Treatment Considerations:

Spraying in the heat of the day will cause material dry too quickly- before adequately entering tissues. It’s best to apply in the morning to allow adequate time for thorough absorption prior to drying.

Spraying “to wet” with PGRs specifically references spray volumes equivalent to 5gal/1000ft2 (20.4L/100m

2). Care should

be taken to avoid spraying “to drip” or “runoff” since roots can also absorb surplus GA reaching the soil.

Unnecessarily high rates or excessive spray volumes may result in soft, loose and stretched growth.

Handling & Transportation for POTS:

Although shorter durations are preferred, plants can be stored and/or shipped up to one week. Optimal temperatures

range from 38-45F (3.5-7C).

Merchandising Considerations for POTS:

Plants perform and display best in relatively high light levels. Provided the opportunity to select or guide the merchandising environment, avoid low light and warm conditions.

"CALLAFORNIA CALLA POT SUMMARY GUIDELINES” offers a 3-page briefing

with basic characteristics and general culture. Please visit Uwww U.goldenstatebulb.com

◊ These instructions are not prescription guarantees, nor are they recommendations

and/or endorsements of any of the chemicals mentioned herein ◊


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