Haulm killing affects stem numbers in progeny seed potatoes

In the progeny of the large haulm killing trial that Delphy carried out last year in potato seed potatoes, it seems that blowing and spraying gives a much better stem formation than a full-field treatment.

In both Agria and Spunta seed potatoes, blowing and spraying as a strategy for haulm killing results in more than 70 percent more stems in propagation compared to full-field spraying. That is one of the findings that Delphy was able to report during a tour on the Seed Potato Field Day in Swifterbant in Flevoland.

• • Read also: Haulm killing is also possible without Reglone and Finale

Since 2019, the advisory organization and research institute Delphy has been carrying out a major haulm killing trial in seed potatoes and ware potatoes. This is done on behalf of BO Akkerbouw with the aim of testing alternative methods and means after the disappearance of the former haulm killers Reglone and Finale.

Effect on tuber setting and yields

As part of the research, the progeny of two objects from 2020 was planted this spring on the Delphy demo plot in Swifterbant. This was done to examine the effect of haulm killing on, among other things, the tuber setting and the yield of the seed. The first counts of the stem numbers already show remarkable differences, says cultivation advisor Jan Salomons of Delphy.

‘In the object with propagation of Agria seed potatoes, on which the foliage was first folded last year and sprayed later, we now count 38 stems per linear metre. In the object with only full-field spraying with Spotlight and Quickdown, the average number of stems is limited to 22. We also see these large differences in the same demo at Spunta’, Salomons reports.

Demo calls for a sequel

The cultivation advisor emphasizes that it is too early to draw conclusions. ‘But it is striking and it can certainly be interesting for seed potato growers. In any case, in this demo we will still count tuber numbers and determine the yields. This definitely calls for a sequel on a somewhat larger scale. Then we also have to include other strategies for haulm killing, such as haulm pulling or spraying first, then haulm flapping and then spraying again.’

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