Vegetable Cultivation Crop Protection Days:

"Don't walk among the plants, you'll come back covered in white mildew"

"It's been a long time since I've seen it like this." A group of growers stepped into a department with a cucumber trial full of powdery mildew on the afternoon of April 20. The researchers succeeded in their setup. The plant protection products tested can well show their effect: a lot or much less white on the crop.

Explanation by Wessel van Vliet of BASF in the powdery mildew trial in cucumber. Bifasto is a fungicide from BASF that works against this.

Over the past two days, the Vegetable Cultivation Crop Protection Days were held at the World Horti Center in Naaldwijk. On Thursday, it was Royal Brinkman's turn to lead advisers in the morning and growers past the trials set up by Vertify in the afternoon and evening. There, as is tradition, the manufacturers were on hand to provide explanations and answer questions and comments from the field.

Syngenta's trial.

There were questions and comments abound, especially now that the product package is constantly shrinking while new viruses and pests keep popping up. In the years leading up to 2020, when the 'Uitvoeringsprogramma Toekomstvisie gewasbescherming 2030' was drawn up, these were not yet there, a grower rightly noted. Clearly, there is an area of tension and puzzling ideas surrounding the opportunities that still exist.

Explanations at UPL (left) and by Aukje Veldstra of ECOstyle on Fusarium (right).

Fortunately, there are also new techniques and tools that can help growers put the puzzle together. In the plenary part on Thursday afternoon, but also during the workshops, specialists from Royal Brinkman dwelt on these.

Tackling Fusarium curatively and preventively.

Data and drones
The plenary part was kicked off by Henk van Daalen. He looked ahead to 2030 and outlined the four building blocks for achieving the targets imposed while maintaining an 'economic perspective.' Not unimportant, Henk pointed out, which met with nods of approval from the audience. Policymakers, too, realize this, as the inclusion of these words in government plans shows.

Pheromones, shown here from HortiPro's SemeonPro line, attract pests.

Discussing what is possible, Henk dwelt on techniques for prevention and control, among others. For example, mechanically deploying natural enemies helps growers tackle pests better, and data can also be extracted from the greenhouse with systems, which can then be acted on. In the future, probably also using drones. Royal Brinkman is taking steps in that direction with TU Delft, the end goal being precision spraying and even more precise deployment of natural enemies with drones.

Henk reminded the audience that Royal Brinkman is committed to resilient plants, e.g., with the CropTimize concept for resilient cultivation and predicting viruses and pests. Especially if the number of applications of a product is limited, a grower likes to use a product at the right moment. What that right moment is, that's where data can help.

Import problems
Also, a regular feature in the plenary section at the Vegetable Cultivation Crop Protection Days was a presentation by Jeroen Sanders of Vertify. He added the gall mite to the 'import row' of foreign pests that already includes stink bugs, thrips, and aphids.

He then discussed studies in which Vertify is involved, including on biostimulants. After all, what exactly do these do? Proving that is not so easy. The researchers want more evidence than a photo showing 'a very tall plant and a much smaller plant', Jeroen pointed out. They looked at how biostimulants can help crops with cold stress.

Jeroen Sanders of Vertify.

Hygiene, also with resistant varieties
Dirk Timmers of Royal Brinkman emphasized prevention. To this end, HortiHygienz has existed since 2019. Not long after that, the Tomato brown rugose fruit virus (ToBRFV) surfaced, so since then, growers, especially in tomato cultivation, have increasingly been doing their best to preventively keep out viruses and pests.

Also of increasing importance in other crops, as Dirk showed that new problems continue to arise with the New Dehli virus, CABY virus, and, last year, Fusarium in peppers.

Dirk Timmers of Royal Brinkman.

Resistant varieties can help growers fight viruses and pests. However, Dirk pointed out that, now that the first varieties with resistance are now in the greenhouse on a large scale, hygiene remains important. If the infection pressure is high, the virus can still break through the resistance, even in a highly resistant variety, resulting in a mutant. So keeping the virus pressure as low as possible is still best in all cases.

More organic, less synthetic
How growers can do that was demonstrated downstairs in the demo greenhouses in Naaldwijk. Attention was paid to prevention, but also to the means available, 'green,' biological or chemical, to intervene. Royal Brinkman's expectation is that additional biological pesticides, in particular, will become available in the coming years while synthetic pesticides will increasingly disappear from the market. Investing in them is also no longer interesting for manufacturers because of all the regulations.

Luc Kurris assured growers that supplementary feeding does not actually stop biological control agents from eating the pests. On the contrary, a varied diet stimulates their appetite.

In the greenhouses, growers encountered existing, well-known resources but also novelties. For instance, some growers looked surprised at the new supplementary feed products presented by Luc Kurris of Royal Brinkman. By no means are all options known to everyone, as it turned out. Together with AgroBio, they are investing a lot in new products, including pellets.

Looking inside the department with HortiPro and Nufarm's trial.

At a joint trial by Nufarm and HortiPro, growers were shown how to control pepper thrips and California thrips. Among the pepper crop in the demo greenhouse, growers were able to ask questions to Tjeerd Peeters of Nufarm and Eric Kerklaan, and Jürgen Brokelman of HortiPro. Both companies showed how they control thrips with a combination of two agents and with the help of Orius. Pepper thrips, in particular, are a growing problem in several crops.

Aron Boerefijn explaining Neudosan and other products.

Do new crop protection substances actually come onto the market anymore? Yes, fortunately for growers, they do. At Certis Belchim, Aron Boerefijn presented the product Neudosan. The broad-spectrum contact agent will be available from next week. Growers in numerous crops can use it to tackle whiteflies, aphids, spider mites, and thrips, while the product also has an effect on mealy bugs, scale insects,  and cicadas. However, that was not where Aron's focus was on Thursday afternoon.

The pesticide, which has already gained a lot of experience internationally, will also be available in soft fruit next year. Moreover, SKAL approval is being worked on. This is expected in the course of this year. Another slightly less new agent that Aron also told us about is Azatin. The substance received a fruiting vegetable authorization at the end of 2022, just not for peppers. Following a question from a grower, the specialist indicated that an authorization for this crop is not expected any time soon.

Koen Bol of Royal Brinkman.

Koen Bol of Royal Brinkman presented the tool Agro4all, which should help growers put the crop protection puzzle together. A free 1.0 version is available to growers. The growers present were keen to use the tool if only to avoid having to enter  'the same information into all kinds of systems eighty thousand times,' as one of them put it. One handy feature of the tool is that it counts against a grower's maximum number of permitted applications. When these are exhausted, the pesticide disappears from the choice list.

It is already more common in Spain, 'islands' of host plants to help natural enemies of pests. Royal Brinkman is working to make this more common in the Netherlands too.

"I won't ask you to walk among the plants, as you will come back white," joked Wessel van Vliet of BASF.

For more information:
Royal Brinkman

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