D. Sugar, S.R. Basile
A high degree of fruit russet is desirable for marketing 'Beurré Bosc' and 'Taylor's Gold' pear cultivars in the United States, but it can be difficult to achieve in the relatively dry production areas of the Pacific Northwest. Copper treatments around the time of petal-fall can be effective in inducing russet, but the effectiveness of copper treatments varies among cultivars and among years. This research evaluated copper treatments in 'Beurré Bosc' and 'Taylor's Gold' pears as related to dosage and application timing, along with an attempt to characterize the interaction of fruit sensitivity and russet-inducing conditions by analysis of weather factors during the bloom and post-bloom periods. Treatment at petal-fall with copper hydroxide effectively induced russet in 'Beurré Bosc' in a relatively wet season, but was less effective when the bloom period was drier. 'Taylor's Gold' was less sensitive to copper than 'Beurré Bosc', and successful russet induction was only achieved in a relatively wet season. Under conditions causing relatively high evapotranspiration, enhanced fruit cuticle development may result in a more effective barrier to copper penetration. However, evapotranspiration, degree day accumulation, and rainfall did not correlate significantly with the effectiveness of copper treatment in inducing russet in 'Beurré Bosc' using a five-year data set. Natural russet incidence in 'Doyenné du Comice' pear over eight years was significantly correlated with all three factors during the period 15–21 days after full bloom.
Sugar, D. and Basile, S.R. (2008). RUSSET INDUCTION IN 'BEURRÉ BOSC' AND 'TAYLOR'S GOLD' PEARS. Acta Hortic. 800, 257-262
DOI: 10.17660/ActaHortic.2008.800.30
Pyrus communis, copper hydroxide, russet susceptibility

Acta Horticulturae