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Pear Chemical Thinning

Like apple, chemical thinning in pear is intended to reduce the current season’s crop load in pursuit of three fundamental goals: 1) inhibit fruit set to minimize green fruitlet hand thinning; 2) improve size and quality of surviving fruit; and 3) promote return bloom to encourage annual cropping. While many pear varieties largely self-regulate their crops without chemical intervention, well-managed chemical and hand thinning programs can increase the long term profitability of some varieties including Bartlett. Some pear blocks can struggle to set commercially adequate levels of fruit and it may be advisable to clearly assess pear set before applying chemical thinners, especially when conditions have been cool and/or wet during bloom.

Target Material Rate per Acre Max/Season REI
(hours)
PHI
(days)
MOA Efficacy Notes
All varieties6-BA
(Exilis 9.5 SC)
9.6 – 25.6 fl oz25.6 fl oz12 h86 d——
6-BA
(MaxCel)
48-128 fl oz128 fl oz12 h86 d——BA may be applied when pears are 5-15 mm in diameter to reduce fruit set, increase fruit size, and promote return bloom.
ABA
(ProTone SG)
6.6 – 33.1 oz66.1 oz4 hnone listed——Target upper portions of tree canopy and apply during slow-drying conditions for better results. ABA may cause significant leaf yellowing and/or abscission.
Organic
metamitron
(Brevis SC)
16 – 48 fl oz48 fl oz12 hours72 daysphotosynthesis inhibitor—Apply Brevis SC between late petal fall and 20 mm fruitlet size. Use a non-ionic surfactant with Brevis SC in applications west of the Rocky Mountains. Consult the product label for more information.
Bartlett, BoscNAA
(Fruitone L)
4 – 8 fl oz54 fl oz48 h2 d——See label for details
NAA
(PoMaxa Plant Growth Regulator)
4 fl oz32.00 fl oz48 h2 d——Can be used to thin pears 15-28 days after full bloom. For best results, apply NAA products with a surfactant (wetting agent) when temperatures are between 70 and 75 F.
Naphthaleneacetamide
(Amid-Thin W)
1.6-8 oz20.9 oz48 h2 d——
Bartlett, Bosc, ComiceNAA
(Refine 3.5 WSG)
12 – 20 oz24 oz48 h2 d——
NAA
(Refine 6.25L)
8-12 fl oz16.00 fl oz48 h2 d——Can be used to thin pears 15-28 days after full bloom. For best results, apply NAA products with a surfactant (wetting agent) when temperatures are between 70 and 75 F.
All varieties 4 options
6-BA
(Exilis 9.5 SC)
Rate per Acre 9.6 – 25.6 fl oz
REI (hours) 12 h PHI (days) 86 d MOA —
More details
Max/Season 25.6 fl oz
Efficacy —
6-BA
(MaxCel)
Rate per Acre 48-128 fl oz
REI (hours) 12 h PHI (days) 86 d MOA —
More details
Max/Season 128 fl oz
Efficacy —
Notes BA may be applied when pears are 5-15 mm in diameter to reduce fruit set, increase fruit size, and promote return bloom.
ABA
(ProTone SG)
Rate per Acre 6.6 – 33.1 oz
REI (hours) 4 h PHI (days) none listed MOA —
More details
Max/Season 66.1 oz
Efficacy —
Notes Target upper portions of tree canopy and apply during slow-drying conditions for better results. ABA may cause significant leaf yellowing and/or abscission.
Organic
metamitron
(Brevis SC)
Rate per Acre 16 – 48 fl oz
REI (hours) 12 hours PHI (days) 72 days MOA photosynthesis inhibitor
More details
Max/Season 48 fl oz
Efficacy —
Notes Apply Brevis SC between late petal fall and 20 mm fruitlet size. Use a non-ionic surfactant with Brevis SC in applications west of the Rocky Mountains. Consult the product label for more information.
Bartlett, Bosc 3 options
NAA
(Fruitone L)
Rate per Acre 4 – 8 fl oz
REI (hours) 48 h PHI (days) 2 d MOA —
More details
Max/Season 54 fl oz
Efficacy —
Notes See label for details
NAA
(PoMaxa Plant Growth Regulator)
Rate per Acre 4 fl oz
REI (hours) 48 h PHI (days) 2 d MOA —
More details
Max/Season 32.00 fl oz
Efficacy —
Notes Can be used to thin pears 15-28 days after full bloom. For best results, apply NAA products with a surfactant (wetting agent) when temperatures are between 70 and 75 F.
Naphthaleneacetamide
(Amid-Thin W)
Rate per Acre 1.6-8 oz
REI (hours) 48 h PHI (days) 2 d MOA —
More details
Max/Season 20.9 oz
Efficacy —
Bartlett, Bosc, Comice 4 options
NAA
(Refine 3.5 WSG)
Rate per Acre 12 – 20 oz
REI (hours) 48 h PHI (days) 2 d MOA —
More details
Max/Season 24 oz
Efficacy —
NAA
(Refine 6.25L)
Rate per Acre 8-12 fl oz
REI (hours) 48 h PHI (days) 2 d MOA —
More details
Max/Season 16.00 fl oz
Efficacy —
Notes Can be used to thin pears 15-28 days after full bloom. For best results, apply NAA products with a surfactant (wetting agent) when temperatures are between 70 and 75 F.

Note: No additional notes provided.

Note: No additional notes provided.