Chemical thinning using Brevis on pear cv. ‘Conference’, effect on fruit quality and fruit size

In three meetings with pear growers associated with the BFV cooperation results of thinning trials during five years with 6-BA and Brevis (metamitron) on cultivar ’Conference’ were presented. The focus was on the effect of thinning on fruit quality and size. Currently, attention is paid to external fruit quality (background colour, bronzing and shape) in price setting, whereas internal fruit quality (firmness, % brix, taste) is largely neglected. However, the latter is becoming more important since consumers and export markets demand high quality and tasteful pears.

Effect thinning (Brevis vs. hand thinning) on fruit quality:
- No effect on bronzing.
- Small increase in firmness with thinning down to approximately 100 fruits per tree.
- Hand thinning does not change the green background colour, whereas it becomes slightly more intense after Brevis based thinning.
- Increasing % brix (more than 1%) with increasing thinning.
- A strong positive correlation between % brix and taste and a weak negative correlation between % brix and firmness.

Effect thinning on fruit size:
- Hand thinning and chemical thinning (except 6-BA combined with NAA) have a positive effect on fruit size.
- Brevis shows a clear dose response but there is a risk of over thinning with higher doses (twice 1.1 kg/ha or more, once or twice 2.2 kg/ha). In addition, a thinning effect is always obtained with Brevis and it has a good effect on fruit size.
- Hand thinning and one Brevis application of 1.1 kg/ha at 8 mm fruit size result in the highest economic gain (± €1500/ha).
- The weather conditions after the Brevis application influence the thinning effect.

On most ‘Conference’ orchards a mild thinning with Brevis (1 kg/ha at 8 mm or 1 kg/ha at 8 mm and 0.5 kg/ha at 14 mm) is advised to the growers.


Eclaircissage chimique sur poiriers cv ‘Conference’. efficacité et influence sur la production et la qualité ()
Activity type
Participation in other stakeholder meeting
Activity work package
Secure sustainable fruit production
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Activity contact
Serge Remy
Fruittuinweg 1
3800 Sint-Truiden, Belgium
Tel.: +32 (0)11 69 71 50
Email: [email protected]
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The EUFRUIT thematic network has received funding from the
European Union's Horizon 2020 research and innovation programme
under grant agreement No 696337.