Agriculture Reference
In-Depth Information
or with a pole. Over the past 30 years, recommendations for the spacing
between thinned apricots have ranged from 1 to 2 inches to 6 to 8 inches. A
good compromise is to leave an average of one fruit every 3 to 5 inches (6
to 10 fruits per 30 inches of fruiting wood); this will produce large fruits and
economical yields. If possible, leave only one fruit per cluster.
As yet, no effective and reliable chemical thinners are available for organ-
ic apricot production. Remember that apricots are easily damaged by sulfur,
and liquid lime sulfur (LLS) should not be applied to apricot trees.
Cherries
Although trials are still underway around the world, thinning sweet cherries
remains controversial. For most varieties on vigorous rootstocks, flower or
fruit thinning is not required. For self-fruitful varieties on highly productive
rootstocks, small fruit size has been a problem. While chemical thinners have
been effective in reducing fruit loads, the reduction in crop load has gener-
ally not increased fruit size.
Washington State University has been conducting experiments using the
tractor-mounted string thinners discussed earlier to thin sweet cherries. The
best results generally come when the trees are thinned when the buds have
swollen to about
⁄
4
inch in early spring. The results show some promise for
1
thinning, but they are too preliminary to make recommendations.
For self-fruitful varieties grown on Gisela 5, Gisela 6, and other highly pro-
help manage crop loads.
Tart cherries do not require thinning.
Peaches and Nectarines
Peaches and nectarines require thinning to develop large fruits. Thinning is
also required in commercial orchards for fruit destined for processing in or-
der to achieve uniform sizes. Hand thinning has been the standard and is still
required in commercial orchards. Researchers are testing both mechanical
and chemical thinners, and mechanical thinners have proven very effective
