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  • Author or Editor: M. W. Williams x
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Abstract

(2-Chloroethyl)phosphonic acid (ethephon) applied to ‘Delicious’ apples before harvest to improve fruit quality can change fruit shape (length/diameter ratio) the next year. The change is magnified when ethephon follows a summer application of succinic acid-2,2-dhnethylhydrazide (SADH) and is most evident on low vigor trees.

Open Access

Abstract

A method is described for introducing small quantities of chemicals by gravity flow into terminal shoots of young apple trees. The destruction of acid fuchsin and 14C labelled growth regulators by this method was down the main stem, out to the lateral branches, and into the leaves.

Open Access

Abstract

Limb units and whole trees of ‘Delicious’ and ‘Golden Delicious’ sprayed in the fall with 250 ppm, 500 ppm and 1000 ppm Ethrel significantly decreased fruit set and vegetative growth the following season.

Open Access

Abstract

The application of cytokinins and gibberellins alone and in combination to ‘Delicious’ apples just after full bloom affected fruit shape by increasing the length-to-diameter ratio of the fruits. Cytokinins caused fruits to be longer with prominent well-developed calyx lobes. The treated fruit had the appearance of fruits grown where early season temperatures are cool. Gibberellin A4 + A7 caused fruits to be longer but did not appreciably affect the development of the calyx lobes.

Open Access

Abstract

Fruit color and quality of ‘Golden Delicious’ apples was directly related to the nitrogen content of the tree. When leaf-nitrogen (N) levels were above 2.2% dry weight, the fruit tended to be large and green. Maximum yields of high-quality fruit were obtained when leaf-N levels were from 1.9 to 2.1% dry weight.

Open Access

Abstract

In 3 different seasons watercore began to develop in ‘Delicious’ fruit as the minimum temperatures dropped to near 4°C. In 1970 and 1971 watercore started to appear just before a sharp rise in sorbitol level occurred in the limb sap. In 1972 considerable watercore developed in the fruit before a significant increase in sorbitol was observed in the sap.

Open Access

Abstract

Lanolin bands containing 2, 3, 5-triiodobenzoic acid (TIBA) applied to the pedicel of apple fruits 2 to 3 weeks after bloom caused the fruits to drop. Naphthaleneacetic acid (NAA) applied to the cut end of defruited pedicels prevented pedicel abscission, but a band of lanolin containing TIBA at mid-pedicel caused most of them to abscise. Cytokinins did not prevent pedicel abscission. Indole-3-acetic acid (IAA) and gibberellins A3 and A4,7 more effectively prevented pedicel abscission of ‘Delicious’ than ‘Golden Delicious’.

Open Access

Abstract

Succinic acid 2,2-dimethylhy drazide (Alar) applied commercially to 'De licious’ apple trees at a concentration of 1,000 ppm at 8 and 125 days after full bloom in 1968 caused flattened misshapen fruit to be produced in 1969.

Open Access

Japanese plum (Prunus salicina Lindel. `Casselman') trees exposed to three atmospheric ozone partial pressure treatments were sprayed with a summer application of Volck Supreme oil (1% aqueous solution) to control an outbreak of spider mites (Tetranychus spp.). Phytotoxic effects were observed on the foliage of trees in the plots exposed to ambient or higher atmospheric ozone partial pressures 5 days following spray application. Foliage on trees exposed to 0.044 and 0.081 μPa·Pa-1 ozone [12-h mean (8 Apr. to 12 June 1992)] partial pressures developed water spotting and more foliage abscission than trees exposed to charcoal-filtered air (0.024 μPa·Pa-1 ozone). Thus, ozone air-pollution stress may predispose plants to increased phytotoxicity from summer oils.

Free access

Abstract

A survey for dead spur was made by rating 8600 ‘Delicious’ apple trees (Malus domestica Borkh.) on seedling rootstock in 3 of the 4 major apple-growing areas of Washington. Only ‘Earlistripe Delicious’ was found to be appreciably affected, and no difference in incidence of dead spur was observed among the areas.‘Oregon Spur Delicious’ and ‘Earlistripe Delicious’ were rated on 5 rootstocks and no rootstock effect was detected. Dead spur symptoms on trees of other strains or cultivars and on pollenizer limbs grafted into ‘Earlistripe Delicious’ affected by dead spur suggest the disorder is transmissible. In addition, an association was noticed between cultivars with long leggy-type growth and the occurrence of dead spur.

Open Access