Chemical thinning of ‘Conference’ with metamitron (Brevis)

Key words: 6-BA, metamitron, fruit weight

The acreage of pears in Belgium has grown steadily over the past 20 years and since 2008 it exceeds the acreage of apples. In 2015 375 million kg of pears, of which 90 % Conference, has been produced on 9.340 ha. With the increase of the production, the size of the pears is an increasingly important factor for the determination of the price. To obtain a higher average fruit weight, the number of fruits per tree has to be optimized, for which the new options are discussed .
Before the authorization of the chemical thinning agents 6-BA (Globaryll 100 and Exilis) and metamitron (Brevis) hand thinning was the only way to reduce the number of pears after an abundant fruit set. But because of high labour costs, chemical thinning is preferred.
The result of the chemical thinning depends on temperature, tree vigour, pollination (the number of seeds), the difference in fruit size and the light intensity 14 to 30 days after full bloom. Mostly the thinning effect of 6-BA (Exilis and Globaryll 100) with ‘Conference’ is too weak and ‘overthinning’ rarely occurs. Metamitron (Brevis), however, can give an excessive thinning, especially when the dose is too high or when the treatment is repeated. Therefore our advice is to use 6-BA (Exilis or Globaryll 100) when only a mild thinning is intended. On trees with an abundant number of flower buds and ideal weather during bloom 1 treatment with 1.1 to 1.5 kg/ha Brevis (metamitron) is recommended. The optimal time for the application of Brevis is at an average fruitlet diameter of 8 to 12 mm on the 2-year-old-wood. A later application is possible, but the gain on average fruit weight is yet compromised and results are more inconsistent. An earlier application is less effective.


Chemical thinning of ‘Conference’ with metamitron (Brevis) ()
Activity type
Participation in scientific conference
Activity work package
Secure sustainable fruit production
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Activity contact
Vercammen Jef
pcfruit, Fruittuinweg 1, 3800 Sint-Truiden, Belgium
Tel.: +32 (0)11 69.70.81
E-mail: [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.