Chemical thinning with Brevis on pear cv. 'Conference' and its effect on fruit size and fruit quality

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.


Chemische dunning met Brevis: pear cv. 'Conference'. Invloed op vruchtmaat en kwaliteit ()
Activity type
Participation in other stakeholder meeting
Activity work package
Secure sustainable fruit production
Activity number
Activity contact
Serge Remy
Fruittuinweg 1
3800 Sint-Truiden, Belgium
Tel.: +32 (0)11 69 71 50
Email: [email protected]
Activity partner
Activity country
Last edit
Event name
BFV, Belgische Fruit Veiling, fruit growers cooperation
Event location
Sint-Truiden, Belgium
Event participants
approximately 80 Flemish pipfruit growers
Event dissemination
The EUFRUIT thematic network has received funding from the
European Union's Horizon 2020 research and innovation programme
under grant agreement No 696337.