Dutch Crop tour Potatoes - week 28
Different phytophthora approach than last year
After the rain last week, the Innovators are ready to welcome participants in the Boerenbusiness Crop tour generally doing well. It's becoming clear once again that this growing season bears little resemblance to the past two years, especially when it comes to phytophthora control.
Where conditions in 2024 with persistent rainfall were ideal for phytophthoraThis year, it's a completely different story. Thanks to longer dry spells, disease pressure has been significantly lower so far than last year, as evidenced by the reactions of the Crop Tour participants. However, it's still important to be vigilant, says Sander Uwland, arable crop advisor at Bayer.
Considerably lower phytophthora pressure
Daan Tap from Elst in Gelderland is the best example of the lower late blight pressure. "I think I'll spray ten times less this year than last year." Daan sprays approximately every ten days, using a BOS system, which almost all Gewastour participants use. "My late blight pressure was so low that I didn't even spray for two and a half weeks."
Sander Uwland agrees that the pressure is considerably lower this year, but he does think that spraying should be done weekly for maximum protection. Kees Trouw from Hellevoetsluis in South Holland also notices that the phytophthora pressure is considerably lower this year. He sprays every seven to ten days, but says he's on top of things. "If the phytophthora hits you, you have nothing left to spray curatively. You have to be on top of it preventatively, you really have to stay ahead of the curve; everything has to be focused on protection."
Alex van Erp from Midwolda in Groningen also notices that the pressure is much lower than last year. "The conditions aren't really conducive to late blight; there's no high humidity, and the number of dew nights isn't too bad. Smart spraying is more important now than a consistent schedule," says Alex. Last year, he sprayed every four to five days. "Back then, it was all around you. You don't think about it, you just spray. In that respect, this year is different."
According to Sander Uwland (Bayer), the differences compared to last year are significant. "Back then, the potatoes were already showing signs of disease, but this year we're seeing a much calmer development with longer dry periods. As a result, the spraying frequency is considerably lower now; this season, we're getting by with a third of the number of sprays compared to last year."
The outlook for late blight also appears favorable. While July has been characterized by changeable weather for the past two years, the weather forecasters predict a very different course this year. After last week's rainfall, the weather looks set to remain dry for the foreseeable future.
Alternaria
Brian Salomé from IJzendijke (Zeeland) is not so much talking about phytophthora, but rather about would alternateBrian says the pressure in his area is quite high. "Normally, I start spraying for alternaria after the crop has flowered, but this year I started much earlier, even before the crop was in bloom." Bert Westhoff, technical product advisor at BASF, also emphasizes the importance of starting alternaria control early. In an interview with Boerenbusiness He says: "We've seen in our trials that correct timing of alternaria sprays is crucial for effective control. Starting too late always costs money."
Status of the crops
Participants are generally quite satisfied with the Innovators' progress, as they approach the second week of July. Alex van Erp is one of them, saying: "The crop is a truly dark green, and despite it being quite dry, the precipitation always came at just the right time. The crop isn't wearing out yet, so I'm curious to see what happens."
Brian Salomé is a little more reserved, indicating that the crop has suffered considerably from the drought. "It's still an open crop, but luckily it's still nice and green. Because of this, I also notice that the crop hasn't suffered much damage from the heat last week." Daan Tap is also having a hard time with rain this year, he says. "My crop is wearing out quickly due to the drought and heat. You can just see it deteriorating at the moment." Daan has irrigated his potatoes this year, but says that irrigation is over for now. "I'm about below the contracted kilos, and I don't want to incur too many more costs."
Kees Trouw is very pleased with the crop's condition. "We've had 30 millimeters of rain, which is fantastic for this time of year. The crop is beautifully green and hasn't suffered from the heat." He believes the later planting has been an advantage. "It might only be a week's difference, but it's made all the difference. Growers who planted earlier clearly see that their crops suffered more from the heat." When Kees pulls a plant from the ground, he sees that all the tubers are already gone, with about eight to ten tubers per plant. "If this trend continues, I expect a decent yield."
Jan Willem Veldman
© DCA Market Intelligence. This market information is subject to copyright. It is not permitted to reproduce, distribute, disseminate or make the content available to third parties for compensation, in any form, without the express written permission of DCA Market Intelligence.
