Brought to you by Bayer Crop Science
Make maximum use of all tools against nematodes
What are the latest developments and insights in the field of nematodes? Which cultivation measures are still under-researched when it comes to nematode control? And how do we keep important active ingredients—such as fluopyram in Verango and Velum Prime—effective for agriculture and horticulture for as long as possible? These and many more questions were discussed during a special nematode afternoon for cultivation specialists in Monheim, Germany.
"To stay on top of nematodes, we must learn together, and knowledge sharing—from growers to researchers—is crucial. We know quite a bit about nematodes, but there's still much more we don't know. New technologies will help us advance and deepen our knowledge in the coming years," said strategy lead and potato specialist Albert Schirring, kicking off the afternoon.
As the first speaker, campaign marketing manager emphasized Jan Bongers the great importance of ICM (integrated crop management) in the management of nematodes. "To keep nematodes under control now and in the future, we must use all the tools at our disposal. In my opinion, that always starts with monitoring and sampling, because then you know your starting situation and can work much more targeted," he says.
Furthermore, good soil management, a sufficiently broad crop rotation, the use of resistant varieties, and catch crops are essential components of nematode control. "In my opinion, the use of a nematicide is the final step in nematode control, but an indispensable one. This applies not only to potatoes, but certainly also to crops like lilies and carrots. Without nematicides, we'll be in real trouble in the Netherlands," says Bongers.
We still have a choice now
In terms of choice of remedies, the options are very slim with only three available: Nemathorin® 10G, verango/Velum and Nemguard®. In potatoes – where by far the most nematicides are used in terms of sales – there are only two options: Nemathorin and Verango. Nemathorin has a (side) effect on, among other things, wireworms. Applying Verango gives the plants some extra vitality, which in turn positively contributes to plant health as a whole.
Although Bongers likes to promote Verango as a "basic nematicide" for potatoes, lilies, and carrots, he's not at all keen to dismiss these two alternatives. "Fortunately, there's still a choice now; something that's long been a given in our field. Or put another way: we need all the tools we can to stay on top of nematodes now and in the future."
Harmful nematodes under the microscope
The second speaker of the afternoon was Christoph Braun, a senior researcher at Bayer Crop Science in Monheim. He discussed in detail the life cycle, survival strategy, and damage profile of harmful (plant-parasitic) nematodes – of which approximately 4.100 are known worldwide, and of which around ten species can cause significant damage to agricultural and horticultural crops.
The three most harmful nematodes – potato cyst nematodes Braun examined these nematodes in more detail – Globodera spp., root knot nematodes (Meloidogyne spp.), and root lesion nematodes (Pratylenchus spp.). Regarding potato cyst nematodes, he sees more and more mixed populations emerging worldwide, and populations are also increasingly shifting from G. rostochiensis to G. pallida. (PA 2/1 and 3). "These mixed forms and shifts have made nematode management even more important than it already was," Braun concludes.
With root-knot nematodes—specifically Meloidogyne hapla and Meloidogyne chitwoodi—the researcher emphasizes the enormous number of host plants (over 100 species), which allows populations to expand not only rapidly but also very consistently. He also increasingly sees fungi—such as Colletotrichum (black speckles) – which manifest around root nodules. "Root knot nematodes are therefore not only harmful in themselves, but by weakening plants, they also give fungi the opportunity to attack," says Braun. This "nematode-fungal relationship," he says, also exists between the nematode species Globodera spp. & Yrichodoridae and Rhizoctonia, and between root lesion nematodes (P. penetrans) and Verticillium wilt (Verticillium dahliae).
Regarding root lesion nematodes (Pratylenchus spp.), Braun briefly addresses the damage pattern, which can vary greatly between potato varieties, both in terms of lesions on the roots and the tuber skin. "You sometimes see very different damage to the lenticels from variety to variety. This can make detection quite challenging," says Braun.
Resistance management is no longer optional
Market development manager In his introduction, Dorus Rijkers emphasized the crucial importance of resistance management when using crop protection products. "My main message for this afternoon is that resistance management is no longer optional, but an absolute necessity to keep products effective and operational. Growers, advisors, distributors, and manufacturers all have a clear responsibility to take this very seriously," Rijkers emphasized.
A key source of knowledge and a guideline for preventing resistance development are the FRAC, IRAC, and HRAC classifications for fungicides, insecticides, and herbicides, respectively. These classifications categorize active ingredients into different groups based on their nature and mode of action. "By systematically alternating products from different groups, fungi, insects, and weeds have much less chance to successfully adapt and thus develop resistance to an active ingredient." Rijkers acknowledges that this is now common knowledge among growers and advisors. "But that doesn't mean everyone acts accordingly – and that is precisely what will be essential in the coming years," he reiterates.
Considerate use of fluopyram
For the active ingredient fluopyram—which is not only the basis for the nematicides Verango and Velum Prime, but also for several fungicides such as Propulse and Luna Experience—rotation is an extra complicated factor. Rijkers explains: "Fluopyram is classified as a nematicide in group n-3 (mitochondria complex) and as a fungicide in group 7 (SDHIs). Therefore, the two applications are not mutually exclusive. However, if both Verango and Propulse are applied in the same season, this does mean two or more applications of fluopyram. So it's certainly important to take this into account." To prevent resistance development, a maximum of 250 grams of fluopyram per hectare per year applies to soil application (Verango/Velum Prime) and a maximum of 500 grams per hectare per year for foliar application. Furthermore, it is strongly recommended to choose a product from a group other than the SDHIs (group 7) for the first foliar application after a soil application (with fluopyram).
Rijkers expects that these regulations will not pose a problem for potato cultivation for the time being, but they may pose a problem for lily cultivation, as Luna Experience and Luna Sensation are also frequently used in this sector in addition to Velum Prime. Therefore, the new recommendation for 2026 is: after a soil application of Velum Prime, a maximum of two sprays of Luna Experience and/or Luna Sensation should be applied, always combined with a multi-site/cover fungicide (e.g., Captan or Folpet).
Finally, Rijkers is happy to recap the six "basic principles" for good resistance management: "Ensure a sufficiently broad crop rotation, use nematode-resistant green manures, sample plots – preferably in the autumn because of the greater chance of detection, avoid planting in a plot where nematodes are known to be present, keep machinery clean so that nematodes cannot travel with adhering soil, and ensure an active soil to suppress nematodes."
Practical questions about Verango
During the knowledge session, many practical questions were raised about nematode control, particularly regarding the Verango product. Below are some of these questions and answers.
Which harmful nematodes is Velum-Verango effective against?
Velum-Verango provides excellent control of Globodera pallida, G. rostochiensis, Meloidogyne spp and Pratylenchus spp.
How much can a nematode population be reduced by 0,625 l/ha of Velum-Verango?
In general, there is a significant reduction in nematode proliferation compared to untreated nematodes. However, Verango-Velum (and other nematicides) cannot completely stop proliferation.
Do starter fertilizers have added value in combination with Velum-Verango?
Combining it with starter fertilizers has a neutral to positive effect on nematode control. This positive effect is linked to accelerated root growth in nutrient-rich zones (NP). These zones are attractive for nematodes to feed on. The presence of Velum-Verango in these zones supports effective control.
What works better: broadcast or in-row application?
In principle, the better the product reaches the root zone, the better the nematode control. Therefore, in-row treatment is preferred. In practice, however, no difference has been found in the effectiveness of Velum-Verango against cyst nematodes in England, regardless of whether the wide-area net was applied before planting or in the row during planting.
What can you expect from Velum-Verango against Trichodorus nematodes?
Trichodorids are difficult to control. They survive deep in the soil during the winter, usually beyond the reach of Velum-Verango. Fluopyram is applied to the top 20 centimeters and is immobile in the soil. Therefore, nematodes in the subsoil (>30 cm) are not controlled.
However, with sufficient soil moisture, trichorids migrate to the root zone. In England, suppression of trichorids and a reduction in the transmission of Tobacco Rattle Virus (TRV) has been observed with Velum-Verango.
Does fluopyram also kill beneficial fungi?
Due to the specific action of fluopyram, most beneficial soil fungi and bacteria are not affected.
Is fluopyram susceptible to leaching during rain?
No. Fluopyram is sparingly soluble and mobile in the soil. It remains at the application site.
Can fluopyram negatively affect soil life?
No. Velum-Verango has no negative impact on soil life.
Is there a difference in effectiveness on different soil types?
No. Velum-Verango works independently of soil type.
What is the influence of soil temperature on Verango-Velum?
In practice, no difference in effectiveness has been observed at higher or lower soil temperatures. However, a higher soil temperature does result in increased nematode and fungal activity.
How does pH affect the effect of fluopyram?
The effect of fluopyram is not affected by pH (between 4,0 - 8,5).
What is the influence of temperature and sunlight/UV?
Velum-Verango is stable at both high and low temperatures and does not degrade immediately due to sunlight and/or UV. However, for optimal effectiveness, it is best to work quickly.
Does organic matter affect the effectiveness of Velum-Verango??
No. This does not affect operation.
Up to what densities does Velum-Verango remain effective at the permitted dosage?
Velum-Verango works at all nematode densities.
More efficient nutrient absorption with Serenade
A (soil) application with Serenade Serenade is not only effective against diseases but also ensures more efficient nutrient uptake by the plant. This means Serenade may offer additional possibilities in potato cultivation, particularly for growers in Northeast regions, where lower nitrogen application standards apply.
Serenade is primarily a biological fungicide. It is based on the bacterium Bacillus amyloliquefaciens strain QST 713. This naturally occurring bacterial strain is effective in combating pathogens. When applied to the soil, the spores of the bacterial strain in Serenade settle on the root system of the crop. They then continue to expand as the roots grow (colonize). During this growth, the bacteria produce fermentation products that combat fungi and bacteria. These, together with plant microbes, form a kind of biofilm around the roots. In this way, harmful fungi (and bacteria) are repelled or driven away from the roots.
Serenade also activates the plant's defense mechanism, acting as a kind of vaccine. It activates four specific defense pathways that protect the plant against a wide range of harmful bacteria and fungi.
In potatoes, Serenade ensures better peel quality through its effects against silver scurf (Helminthosporium solani), common scab (Streptomyces), black spot (Colletotrichum) and rhizoctonia.
Effect on stolons and auxins
Besides its fungicide properties, Serenade also contributes to more efficient nutrient uptake, as demonstrated by multi-year trials and field research. This is how it works:
In potatoes, Serenade stimulates the development of stolons. These are the root tendrils with root hairs that provide the potato with water and nutrients. The better the stolons develop, the easier it is for the plant to transport nutrients such as calcium and trace elements to the tuber. This not only benefits yield but also skin quality. A potato plant also produces more auxins after applying Serenade. This hormone is important for the production and development of growth points and for stimulating root growth.
More efficient nitrogen fertilization?
Serenade thus ensures more efficient nutrient absorption. This results in (additional) fixation of nitrogen, calcium, and several trace elements in the tuber.
This fixation effect, particularly of nitrogen, may offer additional opportunities in potato cultivation, especially for growers in NV areas – where a lower nitrogen application standard applies. In follow-up studies, Bayer is investigating how nitrogen fertilizer can be applied more efficiently – in combination with Serenade. These extensive trials are generating new data that will be shared with the field in the near future.
Nemathorin® 10G is a registered trademark of ISK Biosciences.
Nemguard® is a registered trademark of CertisBelchim.
Captan® is a registered trademark of Adama.
