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  • Author or Editor: K. Hickey x
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Selective leaf removal in the proximity of grape clusters is a useful practice to manage fruit diseases and otherwise improve fruit composition. The current recommendation in the eastern United States is to create a fruit zone with one to two leaf layers and to focus removal on the “morning sun” side of the canopy. We evaluated a more intense and an earlier application of fruit-zone leaf thinning relative to current recommendations to determine whether additional benefits could be obtained without a penalty of impaired berry pigmentation or other ill effects of abundant grape exposure. Fruit secondary metabolites and berry temperature were monitored in two different field experiments conducted with ‘Cabernet Sauvignon’ in the northern Shenandoah Valley American Viticultural Area (AVA) of Virginia. One experiment evaluated the effects of no leaf removal, prebloom removal of four basal leaves per shoot, and prebloom removal of eight basal leaves per shoot. The other experiment evaluated the effects of no leaf removal and postfruit set removal of six basal leaves per shoot. On average, exposed grapes heated to ≥30 °C for a 126% longer period (53 hours) than shaded grapes in the postveraison period (from color development through harvest). However, postveraison grape temperatures did not remain above provisional, critical temperature thresholds of either 30 or 35 °C for as long as they did in studies conducted in sunnier, more arid climates. There were minimal differences in berry temperature between east- and west-exposed grapes in the northeast/southwest-oriented rows of the experimental vineyard. Regardless of implementation stage, leaf removal consistently increased total grape phenolics measured spectrophotometrically, and either increased or had no impact on anthocyanins relative to no leaf removal. Grape phenolics and anthocyanins were unaffected by canopy side. Berry total phenolics were increased and anthocyanins were at least maintained in fruit zones void of leaf layers—a canopy attribute that reduces bunch rot in humid regions.

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Agricultural research often involves collecting numerical data in the field, orechard or greenhouse. Traditionally, horticulturists have recorded numerical data by hand and then manually entered the information into a computer or calculator for statistical analysis. In the last decade data loggers and portable computers have made data collection and analysis easier and more efficient. A palmtop computer is a small, lightweight instrument that combines the best characteristics of data loggers and portable computers. In our trial, palmtop computers equipped with a spreadsheet software program were ideal for numerical data entry in the field and were a cost-effective alternative to other devices.

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As public pressure increases to reduce the use of agricultural chemicals, the effects of lower chemical dosages in the orchard on fruit storability must be determined. Based on both artificial and natural damage, minor tufted apple bud moth (TABM) injury (<10 mm aggregate diameter) did not cause significant loss during controlled-atmosphere (CA) storage. However, damage in excess of 10 mm often caused significant weight loss and decay. Damage occurring closer to harvest caused more loss of quality than earlier damage (i.e., during July and early August). Forty percent of apples damaged 1 week before harvest decayed during storage. Several orchard fungicide spray programs were studied, and in 1993–94, all of the tested programs adequately controlled both fruit blotches and rots, and few storage rots developed. These diseases were light in 1993 due to low rainfall during the summer months. Development of the summer diseases were somewhat higher in 1994, but similar fungicide programs provided adequate control of the complex at harvest. Apples inoculated with P. expansum (punctured with a nail) decayed less when stored in 3% CO2 than in 0% CO2 (at both 1% or 2.4% O2). Decay of `Golden Delicious' caused by P. expansum inoculation increased with later harvest (twice as much decay in fruit harvested 14 Oct. than in fruit harvested 23 Sept.–7 Oct.).

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Tufted apple bud moth (TABM) damage had little or no effect onthe soluble solids, starch, or firmness of stored apples. Decay increasedfrom 0% to 18% in `Golden Delicious' and from 2% to 6% in `Delicious' between control fruit and those with the most TABMdamage (> 10 mm aggregate diameter, significant linear relationships R 2 = 0.41 and 0.12, respectively). Weight loss increased 2- to 3-fold in apples in the highest damage category. These results show that the post-storage quality of apples with slight TABM damage (<5 mm aggregate diameter) does not decline more rapidly than undamaged fruit. The best controlled atmospheres for storing undamaged fruit were also the best for storing damaged fruit. Widely varying fungicide spray programs did not influence the quality or decay levels of apples following storage. However, even those fruit from blocks with few or no sprays had very little decay due either to low inoculum or unfavorable environmental conditions.

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