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Home , Araceae, Arum, Calla, Richardia, Zantedeschia, Zantedeschia aethiopica

Since the 1980s, research has been conducted to determine the feasibility of using species as flow- ering potted . In addition, many hybrids have been bred for forc- ing as flowering potted plants (van Scheepen, 1991). Funnell (1993) pro- Crop vides a list of 61 species and commercially available internationally. About 50% of flowering size calla tu- bers are produced in the , Reports The Netherlands and New Zealand produce 45% and India, Sri Lanka, and produce 5% (T. Lukens, personal communications). In the United States, more than 95% of The Zantedeschia is a part calla are grown as flowering potted Calla History and of the family. There are seven plants whereas in about 80% to Culture recognized species and two subspecies 85% are used as cut . of Zantedeschia: Z. aethiopica (L.) Spreng., Z. rehmannii Engl., Z. Genetics and development Jeff S. Kuehny1 jucunda Letty, Z. elliottiana (Watson) Engl., Z. pentlandii (Watson) Wittm., Natural species and hybrids of Z. odorata P.L. Perry, Z. albomaculata calla are diploid with 32 chromosomes (Hook.) Baill. subsp. albomaculata, Z. (Cohen and Yao, 1996). There are a ADDITIONAL INDEX WORDS. Zantedeschia, albomaculata (Hook.) Baill. subsp. number of postfertilization botany, , cultural require- macrocarpa (Engl.) Letty, and Z. incompatability barriers between spe- ments, pests, postproduction, post- albomaculata (Hook.) Baill. subsp. cies with most calla being self fertile. harvest valida Letty. (Letty, 1973; Perry, Development in the United States has alla is a tropical na- 1989). Closely related genera are been concentrated in California, Luther tive to extending Schott., Burbank made crosses within the ge- from Cape Province to East- Schott., Venten., nus Zantedeschia and produced several C Schott., new cultivars at the turn of the century ern Orange Free State, Natal, , Swaziland, Transvaal, Rhodesia, Schott., Adans., (Welsh, 1991). In the 1940s and 1950s , , Angola, and into Schott., Schott., Shibuya (1956), also in California, northern (Letty, 1973; Tjia, Schott., and conducted extensive intercrossing work 1985). The genus Zantedeschia was Schott. (Liberty Hyde Bailey with Z. rehmannii, Z. albomaculata, assigned to calla by Sprengel in 1826 Hortorum, 1976). and Z. elliottiana. His breeding work in honor of Italian botanist Giovanni Calla have two different types of produced spathe coloration covering Zantedeschia (Letty, 1973). storage organs (Funnell, 1992). almost the entire color scale along There are many common names have stemless with variations in the shape and size of and several species. Common names and are an evergreen species. and the , the pattern and include calla lily, pig lily, lily, The remaining species have compact distribution of spots, plant growth aroid lily, zantedeschia, , cape stems or tubers and are . and plant heights. In New Zealand, arum, cape lily, black-eyed arum, yel- The leaves are entire and born on a breeding has been conducted by low arum, cuckoo-pint, jack-in-the- long . The is com- Brljevich of Maungaturoto in 1932, pulpit, lily of the Nile (Funnell, 1993; posed of a fleshy bearing the Matthews of Waikanae started collect- Hoogasian, 1992; Tjia, 1985). Other true flowers, subtended by a single ing and breeding in 1946, and Harrison common names of calla include showy spathe (Corr, 1993; Corr and conducted breeding in the 1960s kleinvarkblom, varkblomme, varkore, Widmer, 1987; Liberty Hyde Bailey (Welsh, 1991). The Brown family of aronskelke, persvarkoor, varkoorlelie, Hortorium, 1976; Tjia, 1985). Central California began breeding calla varkore (Funnell, 1993). Calla may be grown as outdoor in the 1940s; however, homogeneous garden plants, commercial cut flowers strains were not readily obtained, and more recently as flowering potted and the new hybrids were sold as mixed Assistant professor, Department of Horticulture, Loui- siana State University Agricultural Center, 137 Julian plants. Although this plant has not hybrids for many years ( Brown, 1990). C. Miller Hall, Baton Rouge, LA 70803-2120. been widely grown commercially, there The inability of growers to control Approved for publication by the director of the Loui- is an abundance of information on all bacterial soft rot [Erwinia carotovora siana Agricultural Experiment Station as manuscript aspects of calla and it continues to subsp. carotovora (Jones) Bergey et no. 99-28-0290. Company, plant or chemical names are referred to for example only and it is not the intent increase in popularity. Zantedeschia al.] and poor seed collection, decreased of the author to promote the use of any particular brand elliotiana, Z. aethiopica, and Z. demand, production and breeding in or company. The cost of publishing this paper was rehmannii have been grown for cut the 1960s and 1970s. Cultural tech- defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby production or outdoor garden niques for preventing and suppressing marked advertisement solely to indicate this fact. plants for many years (Post, 1959). disease infestation, the development

● April–June 2000 10(2) 267 CROP REPORTS of tissue culture, the development of ground during winter) (Letty, 1973; scape plant ( Letty, 1973; Funnell, true F1 seed lines in the United States Tjia 1985). 1993; Perry, 1989; Tjia, 1989). and a demand for wide range of plants The evergreen species Z. has de- and flowers has revived the calla indus- aethiopica with, ovate-cordate solid ciduous, orbicular-ovate leaves and try and breeding programs. Current green leaves and white spathes at least yellow to gold colored spathes that are breeding programs select for use as 36 inches (100 cm) tall has long been about 12 inches (30 cm) tall, bloom- flowering pot plants and cut flowers. used for cut flowers and container ing in the summer ( Funnell, 1993; Breeders are using the existing hybrids plants (Fig. 1). It flowers in summer Tjia, 1989; Tjia, 1985; Letty, 1973). and species and are breeding for: plant and late fall into early spring in frost Zantedeschia pentlandii (syn. Z. height, a large number of spathes free areas (Letty, 1973; Dole and angustiloba) has deciduous, oblong- (multibranching), spathe size, ease of Wilkins, 1999; Tjia and Funnell, 1986). elliptic to oblong-lanceolate leaves culture, disease resistance, ability to Cultivar selections include the dwarf usually without white spots (Fig. 4). force, fragrance, stem strength and selection ‘Childsiana’, ‘Pink Mist’ a Spathes can be white, cream, ivory, post production longevity (Brown, pink spathe selection, and ‘Green God- pale greenish yellow or yellow, usually 1990; De Hertogh, 1996; Funnell, dess’ with a green spathe. The species with a purple blotch at the base, are up 1993). Golden State Growers has naturalized (perennialized) in many to 24 inches (60 cm) tall and bloom in (Watsonville, Calif.) has, for example, countries, e.g., New Zealand, Austra- the summer ( Letty, 1973; Funnell, introduced 12 new true F1 hybrid seed lia, Mexico, and California. (Dole and 1993; Tjia, 1989). lines over the last 10 years (T. Lukens, Wilkins, 1999; Tjia, 1985). Zantedeschia odorata has decidu- personal communications). In addi- Zantedeschia aethiopica have solid ous, ovate to cordate leaves with milk- tion, in vitro chromosome doubling of green leaves and is the only species to white spathes having a green base and calla by induction of polyploid strains have long, branched rhizomes. All sweet scent (Funnell, 1993; Perry, has been reported by Cohen and Yao other species have compact, disk- 1989). (1996). The combinations of these shaped stems referred to as tubers Zantedeschia albomaculata has de- efforts will potentially increase the (Letty, 1973). ciduous, triangular-hastate leaves and range of hybrids that can be produced. has de- the spathe color ranges from creamy to ciduous, narrow, lanceolate leaves straw colored to pale yellow, with Species and cultivars which are neither spotted nor lobed purple interior bases; flower stems can More than 10 species have been (Fig. 2). The 24 inch (60 cm) tall be up to 18 inches (45 cm) tall (Funnell, proposed for the genus Zantedeschia spathes bloom in summer and range in 1993; Tjia, 1985). (Traub, 1948), later reduced to six color from yellow to lemon yellow and Zantedeschia albomaculata sub. (Letty, 1973). A recent addition brings pink to dark maroon (Letty, 1973; albomaculata has deciduous, oblong- the current number to seven (Perry, Funnell, 1993; Tjia, 1985). hastate leaves, and a plant height of up 1989), with two subspecies (Funnell, Zantedeschia jucunda has decidu- to 30 inches (75 cm) (Fig. 5). The 1993; Letty, 1973). The species fall ous, triangular-hastate leaves that are spathes are white, ivory, pale yellow, to into two specific groups: 1) evergreen always spotted (Fig. 3). Spathes are coral pink, bloom in the summer and (plants with foliage that does not die golden yellow with a purple throat at are not widely used commercially down in the winter) and 2) deciduous the base and are summer blooming. (Letty, 1973; Funnell, 1993; Tjia, (plants with foliage that dies to the This species is used mostly as a land- 1989).

Fig. 1. Zantedeschia aethiopica (L.) Fig. 2. Zantedeschia rehmanni Engl. Fig. 3. Zantedeschia juncunda Letty Spreng. (Letty, 1973). (Letty, 1973). (Letty, 1973).

268 ● April–June 2000 10(2) Fig. 4. Zantedeschia pentlandii Fig. 5. Zantedeschia albomaculata Fig. 6. Zantedeschia albomaculata (Watson) Wittm. (Letty, 1973). (Hook.) Engl. subsp. albomaculata (Hook.) Engl. subsp. macrocarpa showing two forms of leaf (Letty, 1973). (Engl.) Letty (Letty, 1973).

Zantedeschia albomaculata sub. light levels decreased from ambient to macrocarpa has deciduous, triangular- 55% shade and from 55% to 67% shade. hastate leaves that are sparsely speck- ‘Best Gold’ accumulated more dry led (Fig. 6). The summer blooming matter when grown under a combina- spathes are medium and are either tion of either low photosynthetic pho- cream or straw colored (Tjia, 1989; ton flux (PPF) and cooler tempera- Letty, 1973). tures or high PPF and warmer tem- Zantedeschia albomaculata sub. peratures, which parallels the PPF di- valida has deciduous, ovate-cordate versity of its natural habitats (Funnell to ovate-obicular-cordate leaves, and a et al., 1998). In general, recommended plant height of up to 28 inches (70 cm) light intensities are 2,500 to 5,000 fc (Fig. 7). The spathes are ivory to cream (500 to 1000 µmol·s–1·m–2) (De colored with a purple area at the inside Hertogh, 1996). In areas where high of the base and bloom in the summer temperatures are problematic, light (Letty, 1973; Funnell; 1993; Tjia, intensities can be reduced to 2,500 to 1989). 3,500 fc (500 to 700 µmol·s–1·m–2) In addition to the above, there are and in cooler areas 4,000 to 4,500 fc other cultivars and hybrids commer- (800 to 900 µmol·s–1·m–2) are sug- cially available that have characteristics gested (Dole and Wilkins, 1999). highly suited to flowering potted plant There has been some debate con- production (Table 1) (Funnell, 1993; cerning dormancy and flowering of Fig. 7. Zantedeschia albomaculata Golden State Bulb Growers, 1994; calla. Early studies suggested that there (Hook.) Engl. subsp. valida Letty van Scheepen, 1991). was no dormancy and that year-round (Letty, 1973). production of flowers could be Environmental achieved in greenhouses or under pro- rehmanii replanted immediately after requirements tection as long as temperatures are leaf removal, did not grow (Corr and The effects of light intensity, pho- above 60 °F (15.6 °C) and below 80 °F Widmer, 1988). Zantedeschia toperiod, and temperature on flower- (26.7 °C) (Post, 1959; Wilkins, 1985). elliottiana stored dry at 41, 64, or 75 ing and growth habit of calla vary Rhizomes of Z. aethiopica ‘Childsiana’ °F (5, 18, or 24 °C) caused a signifi- between species and cultivar. Light 0.4 inches (1 cm) in size produced cant reduction in flowering, but, there intensity has been studied on ‘Majestic flowers that were smaller and shorter was no significant reduction in flower- Pink’, ‘Pink Perfection’, and ‘Pacific than flowers produced from larger rhi- ing when stored at 54 °F (12 °C) Pink’ (Armitage, 1991). These culti- zomes 0.75 to 1 inch (2 to 3 cm) (Funnell et al., 1988). Zantedeschia vars produced a similar flower number (Welsh et al., 1988). They also found rehmannii ‘Pink Satin’ produced the at ambient light and 55% shade; how- that the time of planting, either before most flowers after dry storage at 41 °F ever flower number was significantly or after drying the rhizomes, did not (5 °C), with reduced flowering at the reduced at 67% shade. Flower stem affect flower size or plant height. How- higher temperatures. Flowering was number of ‘Black Magic’ decreased as ever, rhizomes of Z. elliottiana and Z. significantly greater for tubers that were

● April–June 2000 10(2) 269 CROP REPORTS

Table 1. Zantedeschia species and cultivars used for commercial production (T. Lukens, personal communications; van Scheepen, 1991).

Species and cultivar Flower color

Z. aethiopica (L.) Sprengel Green at base outside, otherwise white Childsiana White Devoniensis Large white Gigantea Sulphur-yellow with small purple-black blotch Green Goddess Green Little Gem Small white Perle von Stuttgart Small white White Giant Large white White Superior Large creamy white White Swan Ivory-white Z. albomaculata (Hook.) Baill. Dark purple inside base, elsewhere white, cream, straw-colored, greenish yellow, or rarely pink Aurata Yellow Best Gold Dark yellow Black Eyed Beauty Cream/white Bridal Blush Naples yellow Cameo Salmon to pale apricot Candy Dark pink Carmine Red Violet-purple Crowbrough White Little Jimmy Cream white Z. albomaculata (Hook.) Baill. subsp. albomacualta White, ivory or cream, rarely pale yellow or coral-pink Z. albomaculata (Hook.) Baill. subsp. macrocarpa (Engl.) Letty Cream or straw-colored Z. albomaculata (Hook.) Baill. ×elliotiana (Wats.) Engl. Yellow, with crimson blotch at the base Hybrid Yellow or Golden Star Bright yellow Z. elliotiana (Wats.) Engl. Bright golden-yellow Galaxy Dark Indian-lake Golden Sun Canary yellow Harvest Moon Lemon-yellow Heart Glow Fiery red Z. elliottiana (Wats.) Engl. ×adlami Leichtlin Sulphur-yellow, black blotch Z. elliottiana (Wats.) Engl. ×aethiopica (L.) Sprengel Elliotiopica Z. elliotiana (Wats.) Engl. ×albomaculata (Hook.) Baill. subsp. albomaculata Taylori Yellow with dark blotch Z. elliottiana (Wats.) Engl. ×pentlandii (Wats.) Wittm. After Glow Rounded, peach-orange, red in throat Aztec Gold Rounded, gold maturing to burnt orange Black Magic Rounded, clear-yellow, throat black Crystal Glow Pale pink Golden Affair Oval, clear yellow Majestic Red Pointed, rich deep red Mauve Mist Pointed, clear mauve Pacific Pink Oval pointed, slightly fluted, bright pink Pastel Magic Pointed with waved edge, clear lemon Pink Persuation Oval to pointed, rich pink Pixie Pointed, apricot Regel Charm Large pointed, blushed orange-red at maturity Vanity Fair Pointed, pale yellow with pink flush Velvet Cream Cream Z. elliottiana (Wats.) Engl. ×rehmanni Engl. Flame Yellow blushing red Z. jucunda Letty Bright golden-yellow with a dark purple area inside at base Lavender Petite Fuchsia-purple Maroon Dainty Violet-purple Mrs. Roosevelt Creamy yellow Z. rehmannii Engl. White to pink or dark purple Carminea Large, dark carmine Crystal Blush White dark purple (at shed) Gem Lavender Lavender purple Gem Rose Deep rose Little Suzy Pink Soft Glow Barium-yellow Tony Aureolin Z. rehmannii Engl. ×albomaculata (Hook.) Baill. subsp. albomaculata Intense pink color Z. rehmannii Engl. ×elliotiana (Wats.) Engl. Brilliant red Z. rehmannii Engl. ×elliotiana (Wats.) Engl. Ragionieri White tinged pink Z. rehmannii Engl. ×pentlandii (Wats.) Wittm. Rounded, mauve-pink Z. rehmannii Engl. ×pentlandii (Wats.) Wittm. Marguerita Salmon-pink Z. sp. Rubylike Rose Deep rose Z. sp. Rubylike Pink Ice Cool pink (to lavender outdoors) Z. sp. Garnet Glow Bright hot pink Z. sp.Treasure Bronze orange Z. sp. Mango Orange red with bronze overlay Z. sp. Super Gem Deep rose (to rose-lavender outdoors)

270 ● April–June 2000 10(2) moist-stored at the same temperatures. rhizomes may affect the gibberellin 100 and 500 ppm as a 10-min dip of Z. Thus, the optimum storage tempera- levels endogenously, sensitivity to ex- rehmanii superba ‘Pink’, Z. elliottiana ture and type of storage environment ogenous levels of gibberellin, and/or ×maculata ‘Yellow’ and Z. varies between Zantedeschia species. the plants ability to absorb gibberellin albomaculata ‘White’ tubers, increased Although long term storage reduced (Funnell, 1993). The application of flowering and flower number as treat- the flowering potential of Z. elliottiana gibberellic acids (GA) is recommended ment concentrations increased (Reiser and Z. rehmanii ‘Pink Satin’, the time for increased flowering of calla as a cut and Langhans, 1993). Gibberellic acid to emergence and flowering decreased flower (Welsh and Clemens, 1992) at 25 ppm and Promalin (GA4+7 + BA, for ‘Best Gold’ (Funnell and Go, 1993). and for flowering potted plants (Corr Abbott Laboratories, North Chicago, It is assumed that reserve carbohydrate and Widmer, 1987; Funnell et al., Ill.) at 100 ppm applied as a preplant depletion is responsible for the flower- 1992; Reiser and Langhans, 1993). dip to ‘Galaxy’, a Z. rehmannii-like ing time span of various species and However, commercially available forms selection, produced the greatest in- hybrids of calla (Dole and Wilkins, of GA are not currently labeled for use crease in total flower number (Funnell 1999). on calla. et al., 1992). A 10-s immersion of Night interruption of calla caused Cultural requirements rhizomes was as effective as 1 or 30 a slight increase in flower number (data min immersions at the GA3 and not reported) (Greene et al., 1932). A Traditionally, propagation of calla Promalin concentrations used in the more recent study indicated that pho- has been by division of rhizomes or same experiment. Thus, quick dips or toperiod (night interruption with a tubers which was conducive to spread spray applications of rhizomes are fea- red to far-red ratio of 8:1) had no of viruses and bacterial diseases, espe- sible methods of treatment for increas- significant effect on the number of cially Erwinia sp. (Brown, 1990; Welsh ing flower number of calla. For cut- leaves or shoots, the number of leaves and Clemens, 1992). Hybridizing, flower production, GA at 150 ppm can before first flower, date of first flower, cultural techniques for preventing or be applied as a spray to established or total number of flowers in the first suppressing disease, increased seed plantings after sprout emergence when growth cycle of Z. elliotiana and Z. production, and the use of tissue cul- leaves are unfurling or expanded rehmannii. However, plants grown ture have radically changed produc- (Golden State Bulb Growers, 1999). with a night interruption were taller tion practices. In vitro or tissue culture Soil beds or pots can be drenched with than those grown under short days techniques for propagation of calla are a 100 ppm GA solution during dor- (Corr and Widmer, 1990). outlined by Cohen (1981) and Ruiz- mancy. Soil should be moderately wet Calla can be forced to flower at Sifre et al. (1996). at time of drench. any time of year if soil temperatures are To produce a 1.5 to 2.4 Calla should be planted about 2 maintained at 55 °F (13 °C) minimum inches (4 to 6 cm) in diameter (flower- inches (5 cm) below the surface of a and air temperatures are less than 77 ing size) two growing cycles of 16 well-drained and sterilized growing °F (25 °C) (Welsh, 1991). However, weeks (minimum) of active growth medium with high organic matter and Z. elliottiana grown at an air tempera- followed by a rest period are required a pH of 6 to 6.5 (Kuehny et al., 1996). ture of 70 °F (21 °C) flowered first, (Welsh and Clemens, 1992). While Drench within 3 d of initial watering followed by those at 59 °F (15 °C). about 80% of tissue cultured tubers to control Erwinia carotovora subsp. Plants grown at 50 °F (10 °C) did not emerge and flower after one growing carotovora (Jones) Bergey, flower until temperature was increased cycle, these are not large enough for a Xanthomonas Dowson, or Rhizocto- above 59 °F (15 °C) (Post, 1936). single tuber to produce a marketable nia DC, the three major pathogens Zantedeschia rehmannii grown at an 4-inch (10-cm) pot (Dole and Wilkins, contributing to the soft rot syndrome. air–medium temperature of 68/77 °F 1999). The number of days between A combination of three commercial (20 /25 °C) flowered sooner and were planting date and bloom decreases the products is recommended for best con- taller with longer peduncles than those later in the year the planting date trol of the three diseases, respectively: grown at 59/57 °F (15/14 °C) (Corr (Golden State Bulb Growers, 1999). 1) streptomycin sulfate (Agri-Mycin and Widmer, 1990). There was no After chemical treatment for dis- 17, Marman USA, Tampa, Fla.) at 100 effect of temperature, however, on any ease (see Disease and Insect section), to 200 ppm [0.5 to 1 lb/100 gal (0.6 characteristic of Z. elliottiana growth. some cultivars should be treated with to 1.2 g·L–1)], 2) fosetyl-Al (Aliette, Golden State Bulb Growers (1999) GA to increase the number of flower- Rhone-Poulenc Ag, Research Triangle recommend a set of temperature re- ing shoots and flowers per shoot (Welsh Park, N.C.) at 13 fl oz/100 gal (1.0 gimes for optimal growth and flower- and Clemens, 1992). Application of mL·L–1), 3) iprodione (Chipco 26019, ing: 1) from planting to 2-inch (5-cm) GA3 (ProGibb, Abbott Laboratories, Rhone-Poulenc, Research Triangle or 3-inch (7.6-cm) sprouts; 75 to 80 North Chicago, Ill.) at 50 to 100 ppm Park, N.C.) at 6.5 fl oz/100 gal (0.5 °F (24 to 27 °C) days and nights, 2) (µL·L–1) as a 30-min preplant dip in- mL·L–1). after leaf unfurling: 70 to 75 °F (21 to creased stem number per tuber of Z. Recommended planting densities 24 °C) days: 55 to 65 °F (13 to 18 °C) elliotiana and Z. rehmannii (Tija, and tuber sizes for producing salable nights, 3) flower coloring (use high 1985). Soaking tubers in GA3 before pots are: 4-inch (10-cm) pot = 1 tuber light): 65 to 70 °F (18 to 21 °C) days planting increased number of shoot 1.75 to 2 inches (4.5 to 5 cm) or 2 50 to 55 °F (10 to 13 °C) nights. bearing flowers and the number of tubers 1.25 to 1.5 inches (3.2 to 3.8 The induction of a floral state in flowers per shoot (Corr and Widmer, cm) in diameter, 6-inch (15.25-cm) calla requires a trigger level of gibber- 1987). In contrast, foliar sprays of GA3 pot = 1 tuber 2.5 inches (6.4 cm) or 2 ellin to proceed (Funnell, 1993). It did not significantly affect plant growth tubers 1.75 inches (4.5 cm) or 3 tubers has been suggested that storage of or flowering. Application of GA3 at 1.5 inches (3.8 cm) in diameter, 8-

● April–June 2000 10(2) 271 CROP REPORTS inch (20.3-cm) pot = 3 tubers 2 inches growth inhibition was achieved with a and Jierwiriyipant, 1988). A 30-min (5 cm) in diameter (Golden State Bulb drench of 4 mg a.i. Bonzi 200-ppm streptomycin dip provided Growers, 1999). Plants can be grown (paclobutrazol, Uniroyal Chemical, the best control of erwinia of calla pot-to-pot until leaves touch, and then Middlebury, Conn.)/per 6.7-inch (17- tubers, while a 1-h 10% formaldehyde spaced on 6-inch (15-cm) centers. cm) pot (28,350 mg = 1.0 oz), while dip was second best (Kuehny et al., Spacing needs may vary by cultivar. A-Rest (ancymidol, SePRO, Carmel, 1998). Chemical treatments did not Recommended planting densities Ind.) at 1, 2, 3 or 4 mg a.i./6.7-inch affect days to emergence or final plant and sizes for cut flower pro- pot had no affect (Tjia, 1987). A soil growth. duction remaining in the field for 2 to drench of 0.5% or 1.0% solutions of Other lesser diseases are crown 3 years are: 1.5- to 1.75-inch (3.8- to paclobutrazol when shoots were 0.75 rot (Pellicularia filamentosa Cooke), 4.3-cm) tuber = 5-inch (12.7-cm) cen- and 1.2 inches (2 and 3 cm) long, which causes a soft decay of the lower ters, 1.75- to 2-inch (4.3- to 5-cm) significantly limited plant height of Z. half of the main rhizome or tuber and tuber = 6-inch (15.2-cm) centers, 2- rehmannii and limited flower number thick feeding . Cercospora to 2.5-inch (5- to 6.4-cm) centers, and if not treated with GA3 (Corr and richardiaecola Atk., C. callae Peck & 2.5-inch (6.4-cm) tuber and up = 8- Widmer, 1991). A 10-min GA3 pre- G.W. Clinton, and Phyllostricta inch × 10-inch (20.3- × 25.4-cm) cen- plant soak however, overcame the ef- richardsoniae Ellis & Evech. affect ter (Golden State Bulb Growers, fect of paclobutrazol. A combination leaves, stalks and flowers. Symptoms

1999). of a 100-ppm, 10-min GA3 preplant of rot (Phytophthora richardiae Calla grown as flowering pot soak and a drench of 2 mg a.i. per 6- Buisman) appear on the lower or outer plants should be fertilized with a com- inch (15-cm) pot of paclobutrazol was leaves at the same time plants begin to plete liquid feed of 100 to 200 ppm N suggested for producing a quality crop flower. Storage rot (Pythium ultimum of a nitrate-nitrogen based fertilizer of Z. Rehmanii superba ‘Pink’ and Z. Trow) is most common on Z. (Golden State Bulb Growers, 1999; albomaculata ‘White’. Sumagic rehmannii and Z. elliotiana. Tomato Kuehny et al., 1996). A 5-month, con- (uniconzole) at 2 mg a.i. per 6-inch spotted wilt virus may also infect calla trolled-release fertilizer (23N–7.8P– pot also produced satisfactory results with symptoms of chlorotic to pale 30.7K) was incorporated in a 50 pine (Reiser and Langhans, 1993). white streaks and circular lesions be- bark : 30 pumice : 20 peat (by volume) Drenches of 0.5 to 4 mg a.i. per 6-inch coming necrotic between the veins of medium at 0.5 and 2 lb/yd3 (0.30 and (15-cm) pot of paclobutrazol are rec- leaves (Pirone, 1978). 1.20 kg·m–3) of N and 0.08 and 0.14 ommended by Golden State Bulb and 0.54 lb/cubic yard (0.32 kg·m–3) Growers (1999) before shoots are 2.5 Insects P (Clemens et al., 1998). A greater inches (5 cm). A preplant spray of 1.8% There are few insects that disturb flower number, greater bloom fresh Promalin at 100 ppm (1.3 table- calla. The grape mealybug weight, more advanced shoot devel- spoons/gal, 5.5 mL·L–1) mixed with (Pseudococcus maritimus Ehrhorn), opment, shorter time to flower, and copper hydroxide 37.5% at 3 table- longtailed mealybug (P. longispinus greatest plant survival was indicated at spoons/gal (20 mL·L–1) or copper Targioni Tozzetti), bulb mite the low N level of Z. albomaculata oxychloride 50 WP at 0.4 oz/gal (3 (Rhizoglyphus echinopus Fumouze & ‘Starlights’. It is important not to g·L–1) is currently recommended for Robin), banded greenhouse thrip overwater the medium before shoot quality production of calla (Kuehny et (Hercinothrips femoralis O.M. Reuter) emergence. It must be kept moist and al., 1996; Beckman and Lukens, 1997). and greenhouse thrip (H. not allowed to dry completely. If the For cut flower production, the haemorrhoidalis Bouche) are among tubers are too wet the incidence of safest and most effective preemergent the insects that have been reported to disease can increase. herbicides for Zantedeschia are damage calla (Pirone, 1978). Field grown calla require N and K terbumeton/terbuthylazine at 1.34 Mealybugs are soft-bodied insects in the greatest amounts and broadcast and 2.67 lb/acre (1.5 and 3.0 kg·ha– that produce a waxy powder over their rates of 268 lb N, 40 lb P, and 357 lb 1), simazine at 1.78 lb/acre (2.0 kg·ha– bodies and have preferred feeding sites K per acre (300 kg N, 45 kg P, and 400 1) or oxadiazon at 1.34 lb/acre (1.5 on the inside of the leaf sheaths of calla kg K per hectare) are suggested for kg·ha–1) (Ingle and Bussell, 1991). (Powell and Lindquist, 1997). Bulb production of Z. elliottiana (Clark and mites have pearly white bodies and Boldingh, 1991). This should be ap- Diseases move slowly on short, reddish legs. plied as a slow-release or soluble fertil- The most common disease of calla Plant injury through feeding damage izer, either as a basal dressing or imme- is a bacterial soft rot caused by Erwinia has been suggested as a mode for diately after planting before the emer- carotovora subsp. carotovora (Kuehny secondary infection of plant patho- gence of shoots. et al., 1998; Corr, 1990; Corr, 1993). gens such as those mentioned previ- No pinching, disbudding or sup- This bacteria causes a foul-smelling rot ously (Powell and Lindquist, 1997). port is required. A plant growth regu- of rhizomes or tubers, leaves and flow- Thrips may feed on developing leaves lator (PGR) however, may be neces- ers, and infected plants will topple at and flowers, expanded leaves and flow- sary for height control when calla are soil level. Before planting, tubers can ers, and on pollen of calla. These feed- grown as flowering potted plants be immersed in a disinfectant or anti- ing habits will cause distortion of flow- (Kuehny et al., 1996). To be effective, biotic to control erwinia infection ers and leaves or the appearance of PGRs must be applied as a drench for (Reiser and Langhans, 1993). Tubers silvery areas on leaves (Powell and uptake by the root system. Foliar sprays treated with sodium hypochlorite, Lindquist, 1997). Transmission of are not adequately metabolized and streptomycin and chloramphenicol also tospoviruses tomato spotted wilt virus the PGR efficacy is minimal. Optimal had reduced erwinia problems (Tjia (TSWV) and impatiens necrotic spot

272 ● April–June 2000 10(2) virus (INSV) by thrips on calla have increase in popularity and offer the Corr, B.E. and R.E. Widmer. 1988. Rhi- not been reported. industry and the public an alternative zome storage increases growth of in the floriculture market. A great deal Zantedeschia elliottiana and Z. rehmannii. Physiological disorders of research has helped establish a good HortScience 23(6):1001–1002. Gibberellic acid treatments can set of production protocols so that Corr, B.E. and R.E. Widmer. 1990. Growth cause flower deformities including calla can be produced with relatively and flowering of Zantedeschia elliottiana misshapen spathes, double spathes and few problems. Continued breeding and Z. rehmannii in response to environ- colored leaves (partially initiated flow- work has helped improve disease resis- mental factors. HortScience 25(8):925– ers) by up to 15.5% at 100 and 22% at tance, flower number, flower size and 927. 500 ppm (Reiser and Langhans, 1993). plant height. Although there are a Corr, B.E. and R.E. Widmer. 1991. Similar results have also been reported large number of calla species and hy- Paclobutrazol, gibberellic acid, and rhi- by Corr and Widmer (1991). The use brids available, producers should be zome size affect growth and flowering of of Promalin may not induce as many careful to select those calla that have Zantedeschia. HortScience 26(2):133–135. deformed spathes (Golden State Bulb been bred for improved disease resis- Dole, J.M. and H.F. Wilkins. 1999. Growers, 1999). tance and plant quality, and purchase Zantedeschia, p. 550–555. In: Floricul- Postproduction and from a reputable source. Areas of ture; principles and species. Prentice Hall, further research include continued Upper Saddle River, N.J. postharvest improvement of disease resistance and De Hertogh, A. 1996. Zantedeschia (calla FLOWERING POTTED PLANTS. chemical treatments, determining the lily), p. C163–172. In: Holland bulb Zantedeschia aethiopica ‘Childsiana’ factors that control bud dormancy and forcer’s guide. 5th ed. Intl. Flower Bulbs removed from the greenhouse when floral inititiation, and development of Ctr., Hillegom, The Netherlands. the spathe was green and at least par- programs for year-round production tially enclosed by the leaf sheath and of calla. Funnell, K.A. 1993. Zantedeschia, p. 683– then held at 75-fc (5 µmol·s–1·m–2) for 704. In: A.A. De Hertogh and M. Le Nard 12 h at 68 °F (20 °C), produced (eds.). The physiology of flower bulbs. Elsevier, Amsterdam, The Netherlands. quality flowers for 26 d with only 13% Literature cited not developing (Plummer et al., 1990). Armitage, A.M. 1991. Shade affects yield Funnell, K.A. and C.G. Downs. 1987. Plants removed from the greenhouse and stem length of field-grown cut-flower Effect of ethylene on spathe regreening in when the spathe was white, fully open species. HortScience 26(9):1174–1176. Zantedeschia hybrids. HortScience 22(6):1333. but with no pollen shed had a Beckman, P. and T. Lukens. 1997. Simple postproduction life of only 11 d. Hy- steps for pot calla success. GrowerTalks Funnell, K.A. and A.R. Go. 1993. Tuber brids stored at 37 to 39 °F (3 to 4 °C) 60(12):49, 54. storage, floral introduction, and gibberel- had good post production life for 7 d lin in Zantedeschia. Acta Hort. 337:167- Brown, J. 1990. California calla breeding. 172. and quality plants were retained 8 d Herbertia 46(2):165–169. after they were removed from Funnell, K.A., B.R. MacKay, and C.R.O. postproduction storage (Nowak and Clark, C.J. and H.L. Boldingh. 1991. Bio- Lawoko. 1992. Comparative effects of Rudnicki, 1990). mass and mineral nutrient partitioning in promalin and GA3 on flowering and devel- CUT FLOWERS. The best method of relation to seasonal growth of Zantedeschia. opment of Zantedeschia ‘Galaxy’. Acta harvesting calla flowers is to cut the Sci. Hort. 47:125–133. Hort. 292:173–179. stems as far down the plant as possible. Clemens, J.D., D.J. Dennis, R.C. Butler, Funnell, K.A., B.O. Tjia, C.J. Stanley, D. A plant should be harvested when the M.B. Thomas, A. Ingle, and T.E. Welsh. Cohen, and J.R. Sedcole. 1988. Effect of spathes are 0.75 to fully open and 1998. Mineral nutrition of Zantedeschia storage temperature, duration, and gib- about 1 d before pollen shed. When plants affects plant survival, tuber yield, berellic acid on the flowering of flowers are harvested and placed in and flowering upon replanting. J. Hort. Zantedeschia elliottiana and Zantedeschia water only, the stems tend to split. Sci. Biotechnol. 73(6):755–762. ‘Pink Satin’. J. Amer. Soc. Hort. Sci. This can be prevented by adding sugar Cohen, D. 1981. Micropropagation of 113(6):860–863. 1 at 0.4 oz/gallon (40 g·L ) and 100 zantedeschia hybrids. Proc. Intl. Plant Funnell, K.A., E.W. Hewett, I.J. ppm 8- hydroxyquinoline citrate and Propag. Soc. 31:312–317. Warrington, and J.A. Plummer. 1998. Leaf pulsed in this solution for 8 to 12 h and mass partitioning as a determinant of dry ° ° Cohen, D. and J.L. Yao. 1996. In vitro hardened at 41 to 50 F (5 to 10 C) chromosome doubling of nine Zantedeschia matter accumulation in Zantedeschia. J. overnight (Tjia, 1985). The flower life cultivars. Plant Cell Tissue Organ Cult. Amer. Soc. Hort. Sci. 123(6):973–979. of Z. aethiopica was 6 to 7 d, while Z. 47:43–49. Golden State Bulb Growers. 1994. elliottiana began to turn green after 7 Corr, B.E. 1990. Calla lilies as flowering Miniatrue colored zantedeschias: Guide- to 8 d (Tjia and Funnell, 1986). Eth- potted plants. Tenn-Flower-Growers-News lines for pot growers. Golden State Bulb ylene had no effect on the regreening 4(4):2–3. Growers, Watsonville, Calif. of Z. elliottiana ‘Best Gold’, and ‘Helen O’Connor’ and no detectable ethyl- Corr, B.E. 1993. Zantedeschia research in Golden State Bulb Growers. 1999. Callafornia : Guidelines for pot grow- ene was produced by the three hybrids the United States: Past, present and future. Acta Hort. 337:177–187. ers. Golden State Bulb Growers, (Funnell and Downs, 1987). Watsonville, Calif. Corr, B.E. and R.E. Widmer. 1987. Gib- Conclusion berellic acid increases flower number in Greene, L., R. Withrow, and M. Richman. Callas are a minor flowering pot Zantedschia elliottiana and Z. rehmannii. 1932. The response of greenhouse crops plant and cut flower that continue to HortScience 22(4):605–607. to electric light supplementing daylight.

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Ind. Agr. Expt. Sta. Bul. 366:20. Plummer, J.A., T.E. Welsh, and A.M. Tjia, B. 1989. Zantedeschia, p. 697-702. Armitage. 1990. Stages of flower develop- In: A.H. Halevy (ed.). The CRC hand- Hoogasian, C. 1992. In season. Florist 26 ment and postproduction longevity of pot- book of flowering, vol. VI. CRC Press, (1):15. ted Zantedeschia aethiopica ‘Childsiana’. Boca Raton, Fla. HortScience 25(6):675–676. Ingle, A. and W.T. Bussell. 1991. Toler- Tjia, B.O. and K.A. Funnell. 1986. Post- ance of zantedeschia lilies to herbicides. Post, K. 1936. Further responses of miscel- harvest studies of cut zantedeschia inflo- Proc. 44th New Zealand Weed and Pest laneous plants to temperature. Proc. Amer. rescences. Acta Hort. 181:451–457. Control Conf. p. 138–142. Soc. Hort. Sci. 34:627–629. Tjia, B. and U. Jierwiriyipant. 1988. Pre- Kuehny, J.S., W.C. Change, and P. Branch. Post, K. 1959. Zantedeschia (calla), p. 847– plant treatments of calla lily tubers to con- 1996. Miniature potted zantedeschias. 851. Florist crop production. Orange Judd trol erwinia. Fla. Orn. Growers Assn. Nwsl. Greenhouse Management and Production Publishing, N.Y. 11(3):6–7. 17–20 Nov. Powell, C.C. and R.K. Lindquist. 1997. Traub, H.P. 1948. The genus Zantedeschia. Kuehny, J.S., G.E. Holcomb, W.C. Chang, Ball pest and disease manual: Disease, in- Plant Life 4:9–32. and P.C. Branch. 1998. Chemical treat- sect, and mite control on flower and foliage ments to control erwinia soft rot of calla crops. 2nd ed. Ball Publishing, Batavia, Ill. van Scheepen, J. 1991. International check- rhizomes. HortTechnology 8(3):353–356. list for hyacinths and miscellaneous bulbs. Reiser, R.A. and R.W. Langhans. 1993. Royal General Bulbgrowers’ Assn., Letty, C. 1973. The genus Zantedeschia. Cultivation of Zantedeschia species for Alblasserdam, The Netherlands. Bothalia 11, 1 and 2:5–26. potted plant production. Acta Hort. 337:87–94. Welsh, T.E. 1991. The New Zealand Calla. Liberty Hyde Bailey Hortorium. 1976. Proc. Intl. Plant Prop. Soc. 40:478–484. Hortus third; A concise dictionary of plants Ruiz-Sifre, G., E. Rosa-Marqez, and C.E. cultivated in the United States and Canada. Flores-Ortega. 1996. Zantedeschia Welsh, T.E. and J. Clemens. 1992. Pro- 3rd ed. Macmillan, New York. aethiopica propagation by tissue culture. J. tected cropping of Zantedeschia tubers and Agr. Univ. Puerto Rico 80(3):193–194. cutflowers in New Zealand. Acta Hort. Nowak, J. and R.M. Rudnicki. 1990. Post- 319:335–339. harvest handling and storage of cut flow- Shibuya, R. 1956. In: Intercrossing among ers, florist greens and potted plants. Tim- pink calla, white-spotted calla and yellow Welsh, T.E., J.A. Plummer, and A.M. ber Press, Portland, Ore. calla. Kasai Publishing and Printing Co., Armitage. 1988. Preliminary evaluation of Tokyo. the dwarf white calla lily as a potted plant. Perry, P.L. 1989. A new species of Proc. Intl. Plant Prop. Soc. 38:384–388. Zantedeschia (Araceae) from the western Tjia, B. 1985. Hybrid zantedeschia lilies: A cape. S. Afr. J. Bot. 55(4):447–451. potential new crop for Florida. Proc. Fla. Wilkins, H.F. 1985. Zantedeschia, p. 523– State Hort. Soc. 98:127–130. 524. In: A.H. Halevy (ed.). CRC hand- Pirone, P.P. 1978. Zantedeschia aethiopica book of flowering. vol. 4. CRC Press, Boca (calla-lily) disease; virus; disease; insects, p. Tjia, B. 1987. Growth regulator effect on Raton, Fla. 535–536. Diseases and pests of ornamen- growth and flowering of Zantedeschia tal plants. 5th ed. Wiley, New York. rehmannii hyb. HortScience 22(3):507– 508.

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