Prohexadione-Ca Reduces Russet and Does Not Negate the Efficacy of GA4+7 Sprays for Russet Control on ‘Golden Delicious’ Apples
Year: 2007
Type: article
Abstract: A series of four experiments were undertaken to evaluate the effects of individual and combined applications of prohexadione-Ca (P-Ca) and GA 4+7 primarily on fruit russet, but also on fruit set, fruit weight, early season shoot growth, and fruit maturity of ‘Golden Delicious’ apples ( Malus × domestica Borkh.). A single application of P-Ca (138 to 167 mg·L −1 ) at petal fall (PF) reduced the severity of russet in three of the four experiments; however, multiple applications of 20 ppm GA 4+7 at 10-day intervals beginning at PF generally reduced russet more effectively than P-Ca. P-Ca did not reduce the efficacy of GA 4+7 sprays for russet reduction. However, GA 4+7 sprays reduced the inhibitory effects of P-Ca on shoot growth measured 30 days after PF. A single application of P-Ca at PF had no effect on mean fruit weight at harvest. Fruit size was lowest for the combined P-Ca and GA 4+7 treatment in every experiment, although there was a significant interaction between P-Ca and GA 4+7 sprays on mean fruit weight in only one experiment. There were no consistent effects of P-Ca and GA 4+7 sprays, alone or in combination, on fruit maturity parameters at harvest. These data show that a single application of P-Ca at PF reduced russet severity, and the effects of P-Ca and GA 4+7 sprays on russet can be additive. The economic benefits resulting from a reduction in russet severity after combined P-Ca and GA 4+7 sprays will need to be balanced against their occasional negative effect on fruit size. Chemical names used: prohexadione-calcium [3-oxido-4-propionyl-5-oxo-3 cyclohexenecarboxylate formulated as Apogee (27.5% a.i.)].
Source: HortScience
Authors: Steven McArtney, J.D. Obermiller, A. Green
Institution: North Carolina State University
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: gold
Estimated APC paid: $3,000
OpenAlex ID: W2183484572