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B.S. Wilkins, R.C. Ebel, W.A. Dozier, J. Pitts, and R. Boozer

This study was conducted to determine efficacy of Tergitol TMN-6 in thinning peach blossoms. A pretest was conducted and demonstrated no difference between TMN-6 and TMN-10 in efficacy when applied at full bloom or petal fall and at rates of 20 and 40 mL·L-1. In the main test, Tergitol TMN-6 was sprayed once at 10, 20, or 30 mL·L-1 at full bloom or petal fall and compared to an unsprayed control for 3 years. Tergitol caused widespread necrosis of flower parts including sepals, petals, pistils, stamens and peduncles. There was a difference among chemical treatments with more fruit removed at higher concentrations, although the amount of fruit removed was similar for the 20 and 30 mL·L-1 rates. There was no difference in thinning response at full bloom or petal fall, indicating a wide window of efficacy. There was also a difference among years, which was apparently not related to temperature or relative humidity during time of application. Tergitol caused some leaf yellowing and tip burn especially at the higher rates when leaves were present, but the trees did not appear to be seriously affected. Fruit weight was either not affected or larger in some years from treatment. Unlike higher concentrations, tergitol at 10 mL·L-1 did not negatively impact fruit number per tree at harvest. At harvest, fruit weight, skin blush, firmness, and soluble solids at harvest were not affected by treatment. Tergitol TMN-6 proved to be an effective thinning agent and when applied from full bloom to petal fall at 10 mL·L-1 it did not adversely affect the tree or fruit.

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Michael W. Smith and William D. Goff

Patch budding is a common propagation technique for pecan (Carya illinoinensis) commonly used in the central and western United States, but seldom used in the southeastern United States. Success rates vary, but 75% is normally an acceptable survival rate. Selected budwood and rootstock treatments were evaluated to improve budding success. Additional studies were conducted to evaluate bud forcing techniques that would leave the rootstock intact, allowing a second bud to be inserted if the first patch bud failed. Girdling exceptionally vigorous shoots at the base used for budwood improved success, but neither tip pruning shoots used for budwood or rootstock affected patch bud survival. Patch budding was more successful using budwood from 1-year-old branches than from current season shoots, a finding that greatly extends the window available for propagation using patch buds. The age of rootstock wood at the budding site did not affect patch bud survival. Girdling the rootstock immediately above the dormant patch bud was less effective than top removal for forcing the patch bud in the spring. Application of a lanolin paste of 0% to 5% 2,3,5-triodobenzoic acid (TIBA) or 0.02% 6-benzylaminopurine (BAP) to a girdle immediately above the patch bud was positively related to the percentage of patch buds forcing when tree tops were left intact. The combination of girdling, 5% TIBA, and 0.02% BAP resulted in 76% of the buds forcing compared with 73% forced using top removal. This approach damages trees less and enables a second chance for patch budding on a stronger tree.

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Keizo Yonemori, Ayako Ikegami, Sai Eguchi, Akira Kitajima, Shinya Kanzaki, Akihiko Sato, and Masahiko Yamada

There is a non-astringent type of persimmon that loses its astringency naturally on trees, despite the absence of seeds. This type is called pollination-constant and non-astringent (PCNA)-type. PCNA-type was thought to have originated in Japan as a mutant that terminates tannin accumulation at an early stage of fruit development. This trait is confirmed to be recessive and the PCNA-type must be homozygous in all alleles. In fact, crossing among PCNA-type individuals yields only the PCNA-type in F1, while crossing between PCNA-type and non-PCNA-type yields only the non-PCNA-type. However, a new PCNA cultivar, `Luo Tian Tian Shi', was reported in 1982 to exist in Luo Tian County, China, and this PCNA-type seemed to have different mechanisms to be PCNA-type. Our previous report showed that a crossing between `Luo Tian Tian Shi' and Japanese PCNA `Taishu' yielded both PCNA-type and astringent-type in F1, indicating that the trait of PCNA in `Luo Tian Tian Shi' may be dominant. To confirm this hypothesis, we made crossings between `Luo Tian Tian Shi' and Japanese astringent-type `Yotsumizo' or `Iwasedo', and top-grafted these seedlings for earlier fruiting. As we had some fruits in a total of 25 F1 individuals last year, we investigated segregation of astringency among these individuals. We also confirmed the parental relationships of these progenies by analyzing several SSR markers. We confirmed the segregation of PCNA-type and astringent-type in F1. No mistake of artificial pollination was shown in all individuals by SSR markers. Thus, we concluded that the trait of astringency-loss in `Luo Tian Tian Shi' is dominant and the use of this cultivar as a parent will open a new window for breeding PCNA-type persimmon.

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Gerard Krewer, Danny Stanaland, Oscar Liburd, Jerry Larson, Roosevelt McWilliams, D. Scott NeSmith, Ruperto Hepp, and Ben Mullinix

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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Ed Stover, Michael J. Fargione, Christopher B. Watkins, and Kevin A. Iungerman

`McIntosh' apples (Malus ×domestica Borkh.) display a rapid increase in ethylene production as they ripen, resulting in more preharvest drop and accelerated softening compared with other major cultivars. Economic considerations often dictate a choice between delaying harvest to achieve color development or harvesting earlier to avoid excessive fruit softening and drop. We have evaluated the effects of plant growth regulators (PGRs) and summer pruning on this balance. Treatments were applied to trees in the Mid-Hudson region in New York state in 1995 and 1996, and a subset of treatments was applied in the Champlain Valley region in 1996. NAA, applied at 10 mg·L-1 in 1995 and 20 mg·L-1 in 1996, reduced drop on only one sample date in only one of the three trials. Ethephon at 150 mg·L-1 plus 10 mg·L-1 NAA, accelerated ripening and permitted harvest before substantial drop occurred. However, earlier harvest resulted in smaller fruit size, and if ethephon-treated fruit were not picked within a narrow window, rapid drop ensued, and fruit developed a high senescent breakdown incidence during storage. ReTain, containing AVG, at 124 g·ha-1 a.i. delayed drop in all three trials, but its use resulted in firmer fruit after storage in only two of seven comparisons. Use of ethephon on AVG-treated trees enhanced red color but accelerated drop, although it was reduced less than when ethephon was used alone. Severe late summer pruning accelerated red color development, drop and ripening in both years of the study. AVG was more effective for management of `McIntosh' harvest in the cooler Champlain Valley region than in the Mid-Hudson Valley region. Chemical names used: naphthalene acetic acid (NAA); 2-chloroethylphosphonic acid (ethephon); aminoethoxyvinylglycine (AVG).

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Patricia Garriz, Graciela Colavita, Hugo Alvarez, and Valeria Blackhall

Apple fruit abscission shortly before harvest is a frequent, recurring problem, thereby reducing potential yield. The synthetic auxin 2 (2,4-dichlorophenoxy) propionic acid (2,4-DP) was evaluated for its effect on reducing fruit drop and influencing ripening of `Braeburn' apples, in the High Valley region of Río Negro, Argentina (38°56'S, 67°59'W). Thirteen-year-old apple trees grafted on MM 111 rootstock were sprayed on 4 Mar. 2005, at 162 days after full bloom (DAFB) with 2,4-DP at doses of 0.05% and 0.10% (v/v), applied with an airblast sprayer, until runoff. Each tree was trained to palmette and planted in a single row from north to south with spacing of 2.3–4.0 m. The following measurements were performed: a) accumulated fruit drop, twice per week and b) maturity indices, weekly. Samples of uniform-size fruits were assessed for maturity (n = 20 per date and treatment), from 167 (commercial harvest) to 195 DAFB. On 23 Mar. (at 181 DAFB), cumulative fruit drop for control treatment was 19.9%, whereas 2,4-DP significantly reduced it to 4.90% and 2.94% at 0.05% and 0.10% (v/v), respectively. Reduction in the drop was also significant later, and 2,4-DP at both doses controlled drop comparably. The synthetic auxin did not affect fruit quality and maturation, based upon flesh firmness, starch degradation, and soluble solids concentration. We conclude that 2,4-DP is an effective drop control compound and it is useful as a management tool to increase yield by reducing fruit abscission and to extend the harvesting window of `Braeburn' apples, since it does not affect ripening. Delaying harvest may provide flexibility for scheduling of labor, fruit processing and packaging, cold storage, and marketing.

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B.R. Eastwood

A number of factors have emerged in recent years, grown in importance, and are now converging rapidly to create a window of opportunity for all of us. These factors constitute six separate, but related and important, categories: 1) Decreasing staff in the nation's Cooperative Extension System; 2) increasing complexity of agricultural production technologies; 3) increasing concerns of society; 4) opening of markets globally; 5) increased need for accountability; and 6) rapid progress in computerized information and communication technologies. These factors concurrently are causing greater sharing of expertise and resources across states, institutions, and departments; more cooperation with the private sector; improved openness and communication on issues of interest to the community; greater awareness of our role in the world; and a willingness to consider new approaches. One of these approaches involves the development of comprehensive national decision support resources for producers and those who work with producers in an educational, advisory or service role. This program, which has evolved over the past 10 years, is Agricultural Databases for Decision Support (ADDS). ADDS projects may be developed for any commodity, clientele, or major issue area. Products already available include the National Dairy Database and the National Pig Information Database. Several additional projects are underway and more will be added as interest warrants. The ADDS hallmark applies to those projects that follow the philosophy and meet the criteria agreed to by the greater community of developers and users. ADDS uses the sophisticated search and retrieval mechanism and multimedia capabilities of commercially available software. This software is applied to a cooperatively developed national resource of peer-reviewed materials that are selected by experts for their usefulness.

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Peter H. Dernoeden

Annual bluegrass (Poa annua L.) is an intractable weed problem on golf courses. Much has been written about annual bluegrass, but there is little documentation of regional germination period(s) and the proper timing of preemergence herbicides targeted for the control of the annual biotype (P. annua ssp. annua [L.] Timm.=AB). The objectives of this field study were to determine the optimum prodiamine rate and timing for effective AB control. The turf was a mature stand of `Kenblue' Kentucky bluegrass (Poa pratensis L.) maintained under conditions similar to those imposed for golf course roughs. Three rates of prodiamine (0.36,0.73, and 1.1 kg·ha-1) were applied on three dates in 1995 (11 Aug., 14 Sept., and 13 Oct.) and 1996 (29 Aug., 16 and 30 Sept.). All rates applied 11 Aug. or 14 Sept. 1995, and 29 Aug. or 16 Sept. 1996 effectively controlled AB. None of the rates applied 13 Oct. 1995 reduced AB cover, and the 0.36 kg·ha-1 rate applied 30 Sept. 1996 provided relatively poor AB control. Data and observations indicated that the major germination period for AB was between late September and early December. Effective AB control was achieved whenever prodiamine, regardless of rate, was applied between mid-August and mid-September. These prodiamine rates and this application window may be effective only in relatively high cut turf (i.e., >5.0 cm) in the mid-Atlantic region. Chemical names used: O,O-bis(1-methylethyl) S-{2-[(phenylsulfonyl)amino]ethyl} phosphorodithioate (bensulide); N 3,N 3-di-n-propyl-2,4-dinitro-6-(trifluoromethyl)-m-phenylenediamine (prodiamine).

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Kitren Glozer and Janine Hasey

Production of extra-early cling peach varieties in California typically results in a $988 per hectare loss for Sacramento Valley growers, based on a 2004 University of California cost analysis study. This net loss is due to a number of factors, including lower yields than late-harvested peaches; and pruning, thinning, and harvest labor. The estimated cost per hectare to hand-thin extra-early varieties is $1515, which is 31% of all cultural costs. A conservative estimate for machine thinning with transportation costs would be $136 per hectare, a cost savings of about 90%. Machine thinning operates at about 200 trees per hour with two persons (operator and supervisor), compared to four to six trees per hour with two hand-thinners. In recent years, equipment to mechanically thin and harvest has become more sophisticated. We evaluated different types of equipment and settings in two experimental orchards trained in two pruning systems in 2005. We compared effects of crop load and variability in fruit development at time of shaking, as well as the timing of shaking with respect to fruit growth after bloom and compared mechanical and hand thinning. We found an optimum “window” for mechanical thinning based on fruit size and crop load, with tree architecture less important than these factors. Machine-thinning with follow-up hand-thinning reduced the thinning time by 30% to 41%. When machine thinning without follow-up hand-thinning was compared to hand-thinning alone, total yield was improved by 22% and salable yield was improved by 18% in the machine-thinned trees. The net increase in undersized yield in the machine-thinned only treatment was less than 6%.

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L. Jones and R.A. Criley

The most popular Ficus for interior conditions is F. benjamina, which has many clonal selections but still drops its foliage too readily. We compared 4- to 5-foot-tall, shade-grown plants of F. nemoralis, F celebensis, F. binnendykii `Alii,' F. oblongifolia (?), and a selection of F. benjamina thought to be `Gulfstream' with F. benjamina `Exotica' that were transferred to the Hamilton Library of the Univ. Hawaii after 14 weeks under 50%, 65%, or 85% Saran shade. During a 9-week evaluation period, new growth, leaf drop, and photosynthesis were determined. Little new growth developed on any plants during the evaluation period in the library. Leaf loss was greatest for F. benjamina `Exotica,' followed by F. celebensis, while the other four species suffered little leaf loss. Leaf loss was greater for plants grown under 50% shade than for 80% shade, while leaf loss from plants produced under 65% shade was either greater or less than 80% shade, depending on species. Leaf loss was greater in low light sites (13.6 μM/m2 per s) than in medium conditions (20 μM/m2 per s) or near windows (29 μM/m2 pers). After the observation period, the plants were to be removed, but library staff asked to retain many plants as they liked the improved atmosphere the plants gave their office and library settings. Most popular for retention were F. binnendykii`Alii,' F. benjamina `Gulfstream,' and F. benjamina `Exotica,' which still looked good despite its high foliage loss initially. The weeping habits of F. nemoralis and F. oblongifolia (?) were not as desirable because of the space they required, although they are performing well after nearly 12 months in the library. F. celebensis, despite its attractive growth habit and foliage, was a disappointment as it lost many leaves and, over 12 months, developed chlorosis and exudation problems.