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  • Author or Editor: Gerard Krewer x
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Experiments were conducted in north Florida and south Georgia to determine the effects of H2CN2 sprays on vegetative and reproductive growth of blueberry. In Florida, mature, field-grown `Misty' southern highbush (Vaccinium corymbosum L. hybrid) blueberry plants were sprayed to drip with 0, 10.2, or 20.4 g·L-1 of H2CN2 [hereafter referred to as 0%, 1.0%, and 2.0% (v/v) H2CN2] on 20 Dec. 1996 and 7 Jan. 1997. During the following winter, mature `Misty' southern highbush and `Climax' rabbiteye (V. ashei Reade) plants were sprayed to drip with 0, 7.6, or 15.3 g·L-1 of H2CN2 [hereafter referred to as 0%, 0.75%, and 1.5% (v/v) H2CN2] on 17 Dec. 1997 and 6 Jan. 1998. For all experiments, plants were dormant and leafless, with slightly swollen flower buds, at the time of spray applications. Generally, H2CN2 sprays increased the extent and earliness of vegetative budbreak and canopy establishment and advanced flowering slightly. The number of vegetative budbreaks usually increased linearly with increasing spray concentrations. In Florida, H2CN2 [0.75% to 1.0% (v/v)] sprays increased mean fruit fresh weight and yield, and shortened the fruit development period (FDP) compared to controls. However, H2CN2 sprays ranging in concentration from 1.5% to 2.0% (v/v) resulted in significant flower bud injury and reduced total fruit yield compared to controls. In south Georgia, 27 of 37 field trials conducted between 1991 and 1998 on several rabbiteye and southern highbush cultivars indicated that leaf development was significantly enhanced by H2CN2. H2CN2 shows potential for increasing early fruit maturity, fruit size, and yield of southern highbush and rabbiteye blueberry cultivars with poor leaf development characteristics in low-chill production regions. Chemical name used: hydrogen cyanamide (H2CN2).

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Bananas are a popular ornamental plant in the southern U.S. However, normally only a few cultivars, such as `Lady Finger' and `Orinoco', are grown in Georgia. Thirty-three primarily commercial cultivars of bananas were grown for two years near Savannah, Georgia to determine their suitability for ornamental and nursery production. Most plants were grown from tissue culture plugs. They where given rates of fertilization used for commercial banana fruit production. Most cultivars produced 10 to 14 leaves and grew to heights of 1.5 to 2.0 m. Some displayed desirable ornamental characteristics such as pink tinted pseudostems, colorful flowers, and large graceful leaves. Many of the cultivars flowered and began producing fruit in late summer, although only `1780', `Raja Puri' and `Sweetheart' produced palatable fruit before frost in November in some years. Cultivars were also rated for their ability to produce suckers that can be used for nursery production. In year two, `1780' and `Manzano' produced the largest number of high quality suckers for nursery production. For the planting as a whole, sales of suckers at a field day averaged $7/per plant in year 2 and $17/per plant in year 3.

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Five experiments were run using surfactants and gibberellic acid (ProGibb). Fruit set is a problem with rabbiteye blueberry plants. Gibberellic acid sprayed on plants when they are in bloom does enhance fruit set. Currently, it costs $247/ha to achieve this enhanced fruit set. `Tifblue', `Climax', and `Woodard' cultivars were used in on-farm experiments. Usually, applications of 80 + 80 are used. With use of X-77 and L-77 surfactants, rates were reduced to 40 + 40. Other rates examined were 32 + 32, 24 + 24, 16 + 16 + 16. Fruit was enhanced significantly over no spraying. Airblast I sprayer performed better PropTec, whether used for day or night applications. Spraying slanting downward produced greater fruit set than from the side. E1: Trt = 15 – 20, C = 11 lb/lo. E2: 32 + 32 = 12, 16 + 16 = 7 lb/lo. E3: AB = 64, PT = 48 %FS; Trt = 56, C = 35 %FS; `C' = 73, `T' = 39 %FS. E4: 5% FS with Trt; `T' = 53, `W' = 57 %FS. E5: 30 + 30 = 87, – 40 + 40 = 80 %FS.

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Abstract

Fruit tissue only was treated with concentrations of 0, 240, 360, 480, 600, 720, 840, and 960 ppm of (2-chloroethyl)methyl bis (phenyl methoxy) silane (CGA 15281) applied to 1/3, 1/2, and 2/3 of the fruit surface. Increased abscission of fruit occurred as ovule length increased from 3.5 mm to 13.3 mm when fruit alone were treated. Foliage sprays of the same concentrations with the fruit protected generally had no effect on fruit or leaf abscission. Application of 0.01 ml droplet of CGA 15281 to the abscission zone, peduncle, and fruit cheek caused little fruit removal, but produced chlorosis of the treated area on the fruit. The data suggest that fruit contact with CGA 15281 is necessary for fruit thinning.

Open Access

Abstract

‘Spalding’ pear (Pyrus sp. Nak) has been released to provide a good quality pear cultivar for home planting in the Piedmont area of the southeast where fire blight is a major problem.

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Georgia has an excellent window for organic blueberry production since much of the crop ripens ahead of production in the northern U.S. Major challenges facing Georgia organic blueberry growers are weed control, organic fertilization, insect control and disease control. A team of Georgia growers, extension agents and scientists are working together to solve these production problems. Since 2002 a series of experiments have been conducted on blueberry establishment and maintenance. Various mulch materials were tested. On young plants, pine straw produced the highest yields, but pine bark and landscape fabric were also successful. With the pine straw treatment, a respectable yield of 0.97 kg/plant occurred 24 months after planting. In addition, a bed shaper–plastic mulch layer was modified by developing a removable center. Using this system, beds are formed, plants are mechanically transplanted, plants are pruned to 75 mm, and plastic is then pulled over the stem. This produces a fairly tight fit around the stem and a nearly weed free system except for weeds growing from the edges. On mature plants, pine bark and wheat straw were tested. Wheat straw produced excellent weed control and improved blueberry growth in year one and two. However, pine bark mulch provided the best weed control in year three. Various organic burn down compounds such as vinegar, Xpress, Alldown, and Matran 2 were tested for winter weed control efficacy. In these trials Matran 2 was the most effective, and the product also performed well on woody weeds that were winter pruned, allowed to resprout and then treated. A propane torch was also tested, but discarded because of the fire hazard. Entrust insecticide was tested for thrips control and gibberellic acid for fruit set. Thrips populations were low, so no effect on fruit set was noted from Entrust. Gibberellic acid significantly improved fruit set.

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