How to Treat Common Disease, Pests and Fungus in Hop Plants.

There’s no easy way around it, hops are prone to many pests and diseases. One of the most common goals with new varieties is resisting common issues, in the hope of lowering the grower’s burden. Regardless hops still need care and treatment to reach their full potential. First we’ll go over some of the most common diseases, how to spot them and the basic treatment they’ll need. Then we’ll have a look at treating your plant in more detail, the alternative solutions along with the pros and cons of each. There is no easy trick to any of this so gaining the knowledge needed to act quickly is invaluable.

Common diseases

Photo from MDPI

Downy and Powdery Mildew are perhaps the most common fungal disease you will run into when growing hops. Mildews are a type fungus that can absolutely devastate your plant’s leaves. Downy Mildews appear as blotches one side and white spores on the other. Usually these blotches are white, yellow or brown in colour. Discolouration isn’t uncommon with older hop leaves so make sure you check for the spores. Powdery Mildew is simply a white power that engulfs the leaf creating similar issues. Weakening photosynthesis, killing young growth and rot Mildew is a huge pain. Luckily it is fairly easily treated with fungicides.

Photo from the British Hop Association

Verticillium Wilt, sometimes simply called Wilt poses a serious challenge for hop growers. Unlike mildew it is found in the soil, and rather than targeting the leaves it starts in the roots. Travelling up the inside of the plant Wilt hampers the delivery of water and nutrients throughout. The common signs look a lot like when a plant is naturally wilting. Sickly and discoloured droopy leaves are the first thing you’ll notice. But upon cutting open the stem, you can see it the inside has gone a dark brown. There aren’t any fungicides that directly target Wilt. However the plant may still recover if dug up, cleaned and replanted. In its place Wilt resistant hops like Phoenix or Target should be able to flourish.

Photo from Nocutts

Fungus is not the only issue hops face, insects pose a great a threat to your plants. Aphids like Black and Greenfly along with similar pests such as Whitefly will be in a constant war with you. They love nothing more than sucking the sap of hop plants, not realising they can be made into something much tastier. They’ll lay eggs on the undersides of leaves and if left unchecked generally take over. Pesticide sprays are the key, normally once a week or fortnight is enough. If an infestation does occur then the plant will have to be sprayed every 2-3 days for the next week at least. This is to catch the eggs they laid, otherwise the plant will quickly be overrun again.

Of course the gardener’s favourites are never far away. Slugs and caterpillars will always be about. For caterpillars usually get caught in common pesticides, but keep an eye out for them and pick them off. Try to put them somewhere nice, we need more butterflies. Slugs though do not get treated so nicely, and that isn’t just a looks thing. The rate they can multiply and decimate plants is a real worry.  While slug pellets are a useful tool, they need reapplied regularly and are not always pet safe. Alternatively then the use of anti-slug nematodes is an effective solution and will only need applied twice a year.

Treatments

So, despite hops having clear vulnerabilities the ways to deal with them are fairly straight forward. Most of the troubles hops face can be treated with off the shelf pesticides and fungicides. If you garden regularly and already spray your plants the same stuff should do the job. Weekly or fortnightly should be enough.

But many naturally worry how these chemicals can affect their crop, many turn to growing their own produce in the hopes of reducing the high levels commonly used in industrial farming. Now the amount you’d be using on your plants is relatively small. Rather than a big machine choking them in a cloud it is a few pulls of a squirty bottle. Whether they are food safe is something you need to check carefully and regularly in case the formula changes. It’s recommended you do wash your hops upon picking even if the label says it’s okay.  This undoubtedly does have some effect though. The whole idea is to get certain chemicals in the plants systems. Some who are less concerned may still not want to directly spray their hop cones. If you would like to avoid this alternatives do exist.

There are many organic sprays you can use instead. Instinctively many turn their nose up at these. Not entirely without reason as they likely will be weaker. If you are only growing a handful of plants though you don’t need the strongest sprays around. Regularly rotating them is more likely to catch diseases than anything else. Of course you should always check the ingredients to see if they are actually all that different from non-organic sprays.

Some have also turned to natural methods of prevention. It isn’t all hippy science either, that focuses on a different type of plant which looks similar to hops. Nematodes are very effective when it comes to deal with vine weevil, and you can get variants that tackle slugs or other pests. Some farms now even employee predatory mites that don’t harm the hops. Typically these need to be reapplied a few times throughout the year. You can’t just set them and forget about it either, problems may get out of their control so you will need to step in. You will also get some harmless insects on your plants, ladybugs and many spider species aren’t likely to hurt your plant and may even nibble on some pests.

Fungus remains a big issue. If you don’t have a large number of hops or plants susceptible to same fungi you may get away with not spraying.  The use of microorganisms to tackle various diseases sadly doesn’t currently target the issues hops face. With clear demand for these types of solutions it is always worth keeping up with the latest developments. For now though there’s no much on offer.

There is one option we haven’t covered yet. Natural resistance. As stated earlier many hops were developed with the goal of not succumbing to common diseases.  Cascade and Mounthood resist Mildews, while Omega and Yeoman resist Wilt. However, despite many hops resist something no hop resists everything. Perhaps then it is a good idea to pair hops with different resistances. If you can prevent or slow transfer and propagation it is less likely to spiral out of control. Always keep in mind resist does not mean immune. These diseases are constantly mutating and your plant may be unlucky.

There’s no easy solution to any of this. It will be work keeping on top of all the potential issues your hop plant could have. The strongest defence your plant can have is staying healthy. If your plant is not getting enough sunlight or roots are overly wet then fungus is more likely. The damage done by pests is much greater if the plant is already low on nutrients. Good health is not a guarantee to your plant fighting everything off, but an unhealthy plant won’t be able to. All the things suggested here help a healthy plant fight to survive. So pick the right plant, best location, figure out a schedule and then go for it.

We sell the hops mentioned here in 9cm and 1L pots. Along with it featuring in packs featuring various varieties.

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