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  • Author or Editor: Brent K. Harbaugh x
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Trachelium caeruleum has been grown in the United States as a cut flower for about a decade. Only two cultivars, `White Umbrella' and `Purple Umbrella', were readily available for commercial use before 1997, but nine new cultivars became available in the last few years. Comparative performance trials have been lacking for these cultivars in the United States. This trial evaluated 11 cultivars of trachelium for cut flower production performance (vegetative and flowering characteristics) and postharvest longevity. The evaluation was in the spring of 1999 at Bradenton, Fla. (27.4 N, 82.5 W; AHS Heat Zone 10; USDA Cold Hardiness Zone 9b). Plant height for all cultivars except `White Umbrella' was above 30 inches (76 cm), a height required for acceptance as a high quality cut flower. `Summer Lake' had the smallest inflorescence diameter of 3.9 inches (10.0 cm) and `Lake Powell' the largest at 6.1 inches (15.4 cm). `White Umbrella' (160 days from seed to flower) was the earliest to flower and `Lake Powell' (169 days) the last to flower. Vase life was as short as 7 days for `Summer Lake' to as long as 11 days for `White Umbrella'. `Lake Powell' (white color group), `Summer Blue Wonder' (blue color group), and `Lake Superior' (purple color group) had the highest overall rankings.

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Before being forced as potted plants, tubers of two Caladium ×hortulanum Birdsey cultivars were subjected to different methods of de-eyeing (terminal bud removal), either before or after 6 weeks of curing and storage. The cultivar Frieda Hemple (`FH'), a type with numerous buds that does not require de-eyeing, was less affected by deeyeing than `Fannie Munson' ('FM'), which has a single dominant bud and requires deeyeing. De-eyeing had little effect on `FH' development. For `FM', regardless of the time of de-eyeing, all treatments reduced height, increased the number of leaves, increased total leaf area, and reduced mean leaf area when compared to intact tubers. However, as the size of the tuber piece removed during de-eyeing increased, the variability within each treatment increased. Based on the results of this research, the best method of de-eyeing would be to destroy or remove the dominant terminal bud while removing as little of the surrounding tissue as possible. The time of de-eyeing can depend on producer preference, since the time of de-eyeing did not affect development significantly.

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Fusarium crown and stem rot, caused by Fusarium avenaceum, is a serious disease of lisianthus, Eustoma grandiflorum Raf. (Shinn.). While more than 80 new cultivars of lisianthus have been released for sale in the United States in the past decade, there is a lack of information on their susceptibility to this pathogen. Forty-six cultivars of lisianthus were evaluated for resistance to F. avenaceum. Cultivars were grouped according to blue/purple, pink, or white colors and evaluated within their color class. Although all cultivars evaluated were susceptible to F. avenaceum, partial resistance was observed as indicated by differences in the length of time to symptom expression and in the frequency of diseased plants. `Ventura Deep Blue' and `Hallelujah Purple' (25%) in the blue group, `Bridal Pink' (23%) in the pink group, and `Heidi Pure White' (53%) in the white group had the lowest frequency of diseased plants at 55 days after inoculation. In 21 of the 46 cultivars, 80% to 100% of the plants expressed symptoms at 55 days after inoculation. Screening cultivars for resistance to F. avenaceum is the first step to breeding and developing resistant cultivars. These results also can be useful to growers who could select cultivars that express some level of resistance as an aid in management of this disease until more resistant cultivars are released.

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