Research project in the Hallertau: Hops should defend themselves against common pests

Hop researchers want to make the plants resistant to a common pest.

The project could be a boon for the industry.

We introduce it.

Nandlstadt

- The biologist and hops researcher Florian Weihrauch from the State Office for Agriculture (LfL) wants to know: Can hops possibly develop a plant's own protection against the common spider mite?

In any case, Weihrauch is firmly convinced of this, even if this year, due to the weather, the dream start for this experiment was not necessarily given.

The red spider, as the spider mite is called in Bavaria, especially likes it dry and very warm - everything else that summer has offered this year.

The FT went in search of clues to Kainrad near Nandlstadt to talk about this innovative approach to an old problem at the farm of farmer Anton Widmann.

The frankincense method, one thing is certain, could potentially change an entire industry if successful.

The attempt should take a total of five years.

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Debriefing: (from left) the student assistant Susanne Kaindl and hop researcher Florian Weihrauch in the field of planter Anton Widmann.

© Richard Lorenz

The hops are already high and the first farms are starting to pluck. In the past few days, however, Weihrauch was still collecting the last samples before the harvest and was two things alike: disappointed and happy. Disappointed because once again he couldn't find a trace of the spider mite on the Widmann hops - but of course also happy for the farmers in the area. Because the red spider is not to be trifled with, Weihrauch knows as well as Widmann. Entire hop gardens can "burn" due to the infestation - and once the spider is there, good advice is expensive.

Widmann gave information: In order to prevent the pest, crop protection treatment is carried out on average once a year in regular cultivation.

However, according to Weihrauch, this does not have to be the case according to his theory - because the hops may be able to develop defense mechanisms themselves after an initial infection, or in other words: as it currently looks, the plant could become resistant to the spider mite.

Significantly less damage after a single infestation

After an infestation, emphasized Weihrauch, the observation would have shown that further damage was significantly less in the following season. The plan is not to watch the disaster more or less, but to intervene much earlier - namely in the greenhouse. In the future, young plants could be brought into contact with the red spider so that they form a natural defense.

Widmann cannot remember a major infestation in his hop gardens, but he can remember smaller nests. But they are also annoying. Currently there are only two options: inject early or let the hops break. A resistant plant would be “ingenious” for Widmann, which is one of the reasons why he hadn't considered taking part in this experiment for long. The hop garden with the Hallertauer Tradition variety has been divided into two plots since the start of the experiment: one does not use acaricides as a spray, the other does not - Widmann is only allowed to use fungicides for both, for example against powdery mildew. Admittedly, said Widmann, this separation does make more work, but new insights are his reward. Should there be a massive spider mite infestation in the coming years,Widmann will be compensated by the LfL for this.

Pest is on the rise

Frankincense is certain that the red spider is on the advance, because it benefits from two circumstances: climate change with more frequent dry and hot days and the political endeavor to minimize plant protection per se.

However, according to Weihrauch, the hop farmer would hardly ever have access to pesticides these days.

It used to be different when “stuff was sprayed, it makes your hair stand up”, such as arsenic against aphids.

The situation is different in the hop-growing areas in America, for example, where chemical interventions have to be carried out four to five times a year due to the climate.

Weihrauch also thinks about beneficial insects in the case of spider mite infestation: the predatory mite does a very good job here in terms of experience and is also used in viticulture, for example.

In addition, the hop specialist is committed to ensuring that varieties with a high alpha acid do not always have to look like the green gold from a picture book.

The “hardcore hop farmer”, emphasized Weihrauch, is of course rather critical of all these innovations.

The young in particular, however, rate a new method of pest avoidance positively.

"A new generation is growing up," said Weihrauch.

There is great interest in the research project

The fact that the project is being carried out in the Hallertau alone in 26 hop gardens and in five cultivation areas in Tettnang also shows that there is interest. "We have come a long way and constant dripping wears away the stone," said Weihrauch, who has been dealing with the subject for 30 years. He is convinced: “When I retire, this method will be an integral part of hop growing.” But until then, numerous samples still have to be taken and evaluated.

And then suddenly the red spider seemed to have been spotted in Widmann-Hopfen at the on-site visit: The LfL student assistant, Susanne Kaindl, shot a sample in the sun - but quickly gave the all-clear. “Just sunburn,” so the diagnosis in Kainrad. No wonder, it was also one of the few bright summer days that Florian Weihrauch had chosen for an inspection of his outdoor areas. While the LfL employees were bagging the hop samples, farmer Anton Widmann was already on the go, because the red spider was nowhere to be seen, but a lot of work.

Richard Lorenz

The harvest begins in the Hallertau.

But what about hops and what yields can the industry hope for?

The planters association gives answers.

Also worth reading: The community of Rudelzhausen was also badly affected by the flood that hit parts of the Hallertau last Monday.

Flood protection against future events remains complicated.

By the way: Everything from the region is now also available in our new, regular Freising newsletter.