Hop Diseases

Our sterile techniques and clean rootstock ensure that none of our hop products carry any hop fungal diseases, including Hop Powdery Mildew, Verticillium Wilt, and Downy Mildew.

All hop tissue cultures at Summit Plant Labs have tested negative for the following diseases. Click on each disease to learn more:


Hop Stunt Viroid (HSVd)

Hop Stunt Viroid is thought to have originated from grapes in Japan, and was confirmed in the United States recently in 2007. Its dormant period of 3-5 years before symptoms occur contributes significantly to the inadvertent spread of the disease. HSVd is spread solely through mechanical means by harvesting or in-field cultivation operations.  It is also spread though infected propagation material such as cuttings or rhizomes.  Symptoms included chlorosis, stunting, and reduced plant vigor.  It causes yield losses of up to 50%, a-acids and b-acids losses of up to 50-70%, and lupulin gland loss of up to 60% when compared to non-infected plants.  HSVd can also be spread to peach, plum, citrus and grape crops.

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Apple Mosaic Virus (ApMV)

Previously known as Prunus necrotic ringspot virus (PNRV), Apple mosaic virus is one of the most deleterious viruses to hop production in terms of losses in yield and a-acids. The effects of the virus are cultivar-dependent, and can cause losses in yield up to 50%, with symptoms worsening with plant age. The virus is spread mainly by plant-to-plant contact through cultural means and root grafting; it is not clear if the virus is spread by an insect vector. Transmittance and symptoms greatly vary with cultivars.

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Hop Latent Virus (HLV)

Hop Lavent Virus is found throughout the world in hop growing regions. It does not cause visual symptoms on any hop varieties. The virus can cause yield losses up to 70% and decreases in alpha-acid levels by up to 44%. The virus usually occurs as a mixed infection with the other carlaviruses Hop Mosaic Virus and American Hop Latent Virus.

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Hop Mosaic Virus (HMV)

Hop mosaic virus (HpMV) was first described in 1907 in the United Kingdom, and has been confirmed throughout Europe, Australia, United States, New Zealand, China, Japan and South Africa.   It typically does not show symptoms except for a few sensitive cultivars such as ‘Chinook’ and ‘Goldings.’ Symptoms include development of a chlorotic mosaic pattern on leaves, and weak bines unable to climb, leading to poor yields and premature plant death. The virus can cause yield losses up to 62% and alpha-acid losses up to 18%. HMV is transmitted by the Damson-hop aphid, the green peach aphid Myzus persicae, and through plant-to-plant contact. The virus usually occurs as a mixed infection with the other carlaviruses Hop Latent Virus and American Hop Latent Virus.

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American Hop Latent Virus (AHLV)

American Hop Latent Virus has only been found in the United States and New Zealand. The virus does not show any visual symptoms on any hop cultivars. The virus can cause yield losses up to 14% and decrease in alpha-acid content up to 12%. The virus usually occurs as a mixed infection with the other carlaviruses Hop Mosaic Virus and Hop Latent Virus.

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Arabis Mosaic Virus (ArMV)

Arabis Mosaic Virus has been reported as a major problem in most hop production areas around the world.  In the United States however, there are historical reports of the virus but no recent ones, suggesting its eradication.  ArMV is spread mainly by the nematode Xiphinema diversicaudatum, which has very little distribution in North America.   It can also be spread by mechanical cultivation techniques.  The virus can cause yield losses of up to 75%, with no effect on resin levels. Infection can cause bare-bine, spidery hop, split leaf blotch, nettlehead and hop chlorotic disease.

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References and Links

Coming Soon

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