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What's Hoppening: Musings from the Hopyard!

What to be on the lookout for in your hop yard

Posted: August 20th, 2019 by hoppenin

The three major arthropod pests of hops in the Northeast are Potato Leafhopper (PLH), Two-spotted Spider Mites (TSSM), and Hop Aphids (HA). This incidence of these pests in hop yards is based on the weather conditions, and we found that the hop aphids preferred cool and moist conditions and populations peaked around the time of harvest through September. For more information about disease, weed, and insect pest populations, check out our six-year study, Organic Hop Variety Trial .

Hop aphids (Phorodon humuli) are small soft-bodied insects that come in both wingless (immature individuals) and winged (adult females) forms, both of which are found on hop plants. Hop aphids are pear shaped and range in color from pale white to a yellowish-green and are found on the underside of the hop leaf. They do not over winter on hops, but rather on a variety of plants in the Prunus genus (Family Rosaceae). Hop aphids over winter as eggs and in early spring the eggs hatch and reproduce asexually for one or two generations before the winged form migrates to hop plants in May. 

These small insects have piercing-sucking mouth parts that are used to feed on the hop leaves and cones, and suck the phloem from the plant. This can cause leaves to curl, and turn cones brown and limp. Hop aphids also release a sugary substance called “honey dew”, which allows for the growth of sooty mold fungi on the hop leaves and cones. While leaf feeding can decrease the marketability of the crop, the bigger threat to hop yield and quality is the sooty mold which results in aesthetic cone damage and a decreased cone quality.

It is important to start scouting early in the season and monitor hop aphid populations throughout the season. One way to control hop aphids is the use of natural enemy arthropods. A list of management tactics and natural enemy arthropods can be found in Hop Aphid, Phorodon humuli (Schrank), in Northeastern Hop yards.

Scouting for Downy Mildew

Posted: June 17th, 2019 by hoppenin

Scouting for downy mildew in the hop yard. Now that the growing season is underway, it is important to be on the lookout for downy mildew! This spring has been very rainy, and the excess moisture on the hop plants creates ideal conditions for downy mildew infections. Downy mildew produces spores in warm, moist conditions and can spread quickly.  Plants are at a higher risk during rainy days because the plant’s stomata, or pores, are open, leaving an open pathway for disease invasion.

Downy mildew is a systemic infection which means that once a plant has downy mildew, it is infected for life. At the end of the growing season, downy mildew will over winter in the crown of the infected hop plant, and re-emerge in the spring.

Infected leaf with downy mildew.

When scouting your hop yard, the first signs of a downy mildew infection are the basal spikes. Basal spikes are chlorotic, or yellowing, and have shortened internodes, or the space between leaf pairs. A severely infected basal spike may also have desiccated leaves.

Other signs of a downy mildew infection are aerial spikes and infected leaves, which will begin to appear as the season progresses. Aerial spikes have the same chlorotic appearance and short internodes as basal spikes, except they’re found on a trained plant rather than on the ground. Infected leaves have necrotic lesions, delineated by leaf veins. These lesions are angular and have very distinct edges, which can help with disease identification.

Downy mildew on basal spikes.

Downy mildew can be managed and there are methods to prevent the spread of infection. When scouting plants, it is important to trim off the infected bines and leaves, and to make sure that infected plant material is removed from the hop yard. If infected leaves have spores, be careful while handling them to reduce the risk of spreading infection.

Increased airflow is another way to reduce downy mildew. It reduces the amount of time your foliage spends wet, which decreases the time that downy mildew is producing spores. Stripping the lower 2 to 4 feet of foliage once a plant is trained and established can reduce moisture.

Biofungicides are another helpful tool to use during the season to control downy mildew, and they can be applied the day before a rain event. There are a variety of conventional and organic fungicides registered for hop use. If you live in Vermont, a list of OMRI-approved biofungicides can be found in the 2016 Hop Biofungicide Trial Research Report.  It is very important to only apply fungicides that are listed in your state for use on hops so be sure to check the label.

Stringing and Training Hops

Posted: May 23rd, 2019 by hoppenin

Stringing often starts in April for many farmers in the Northeast. Stringing consists of tying coir twine to the top supporting wire of the hop trellis and stapling the bottom of twine into the ground next to the hop plant.  Depending on trellising style and setup, 1-4 strings will be run to each crown, though we typically see two in many yards. The strings are inserted into the ground and held in with “W” clips using an insertion tool. This will provide the bines with a means to grow to the top wire in the upcoming season.

Stringing at Champlain Valley Hops in Starksboro, VT.

In commercial hop yards, training dates are determined by cultivar growth in the spring.  Depending on whether a cultivar matures early, mid-season, or late, there is typically a particular range of days for those plants to start their upward growth. Getting the bines off the ground is also important for managing downy mildew and other potential disease issues.

Training dates from 2013-2018, Alburgh, VT.

Year Date
2013 20-May to 27-May
2014 19-May to 30-May
2015 20-May to 26-May
2016 24-May to 25-May
2017 N/A
2018 22-May to 23-May

Training is the process of wrapping shoots around the twine in a clockwise motion. Three to five shoots are selected from the crown to be wrapped around the twine. This process can be time consuming and will play a major role in subsequent plant growth and yield. Choose healthy, vigorous shoots for training that are 2-3’ in length, but avoid training bull shoots. Bull shoots are characterized by having greater internode spacing, hollow stems, and are often purple in color. These shoots will be less productive and more brittle in the wind. The bull shoots do not yield well and should not be trained. Think about leaving some shoots as backups during training.

Regular shoot (top) compared to a bull shoot (bottom).

In general, early harvested hops will have higher yields when trained earlier, whereas late harvested hop will have higher yields if trained later. We look to start training by mid to late May for our early maturing varieties but postponing another week can be beneficial for late maturing varieties depending on growing conditions. In the Northeast, training dates for farmers may fall between mid-May and early-June. We recommend that you make your own observations of hop maturity for each variety and keep detailed records of training dates for your region.

Bull shoots emerging from a hop hill

Crowning and Early Season Downy Mildew Control

Posted: May 6th, 2019 by hoppenin

Hop downy mildew is currently the biggest disease concern for Northeastern hop growers.  Downy mildew overwinters in the hop crown and primary inoculum will be released from the first shoots. Removal of the infected crown or the first flush of spring hop growth is called “crowning” or “scratching”. Shoot removal is used as an early season preventative measure against downy mildew and as a way of managing harvest time.  Hop plants have been budding out for a few weeks now in Vermont and likely most crowning has already occurred. However, scratching or removal of new growth can still be done and may further eliminate infected plant material. Below are some basic tips for crowning and scratching for our region.

1st year hop yards should not be crowned to allow for root establishment.

2nd year hop yards should be crowned if downy mildew was a problem last season.

3rd year hop yards should be crowned if it can be done in April or very early May.

For early season shoot removal any of the following three methods have been used with success in the Northeast.

1. Mechanically cutting and removing the shoots.

2. Flaming after first flush of growth and shoot emergence.

3. Herbicide application. Make sure any pesticide used in your hop yard is labeled for use in your state and on hops.

Since 2014, UVM has been researching the impact of crowning on hop yield and quality. Check out our Hop Crowning Trial final report update to learn more our results.

Crowning was done in the hop yard at Borderview Research Farm in Alburgh, VT on April 25, 2019.

10th Annual Hop Conference

Posted: February 13th, 2019 by hoppenin

We wanted to share a reminder for the upcoming 10th Annual Hop Conference scheduled for Thursday, February 21st.

You can now view the Detailed Agenda for the day.

Register today at www.regonline.com/2019hopconference  

Registration fees are $75 per person, $65 per NeHA member and $35 for the live broadcast.

This year’s live broadcast will be recording all presentations except for the two breakout Foam Brewery sessions, as they will be held in a different room.

If you wish to take advantage of our group rate to stay a night at the DoubleTree by Hilton, you need to reserve before this Friday, Feb. 15th

A block of rooms is available at the DoubleTree by Hilton Burlington only until Feb. 15, 2019 for the rate of $122/night. Call 1-802-865-6600 and use Group Code: HOP or register online at https://bit.ly/2RWJdAP.

Come help us celebrate our anniversary of the 10th Annual Hop Conference!


Hop Field Day

Posted: September 13th, 2018 by hoppenin

Establishing Your Hop Yard – Friday, 9/28/18, 10am to 12pm

Champlain Valley Hops is a growing hop farm in Starksboro, Vermont. The farm goals are to grow and process quality hop products for Vermont brewers. They are currently in the process of improving their land, building hop trellises and planting hops.

Join UVM Extension Northwest Crops and Soils staff Heather Darby, Scott Lewins and John Bruce, along with Champlain Valley Hops crew Peter Briggs and Julian Post to learn how they established their hop yard, including weed management and irrigation strategies. There are 26 acres trellised and 18 acres planted with hop varieties: Centennial, Willamette, Crystal, Cascade, Magnum, Chinook, Nugget.

Free to attend but we ask for pre-registration by 9/25/18 at https://champlainvalleyhops.eventbrite.com or call 802-524-6501 ext. 432






Malt Barley and Hop Quality at Annual Field Day

Posted: July 24th, 2018 by hoppenin

Malt Barley and Hop Quality is just one of the afternoon sessions you can choose to attend at the Annual Crops & Soils Field Day on July 26th at Borderview Farm in Alburgh, VT.  Andrew Peterson of Peterson Quality Malt will talk about malt barley quality and scouting for grain diseases.

The NWCS team will talk about hop quality including harvest timing, crowning, irrigation, scouting for pest and natural enemies, and end-of-season disease management.

Register today for the Annual Field Day –

www.regonline.com/2018cropsfieldday or call Susan at 802-524-6501.

Fee includes a great lunch, Tasting Tent sampling, and Kingdom Creamery ice cream!


Hop Irrigation

Posted: July 2nd, 2018 by hoppenin

  Irrigation system at Borderview Hopyard  

It’s been a hot and dry start to the season and our hops are thirsty! Given our exceptionally dry start to the season and general lack of rainfall, higher irrigations rates may be needed this year to continue healthy bine growth and flower development. Irrigation allows you to apply water directly to your plants and can increase overall yields along with many other benefits. We strongly recommend that you irrigate, but how much water do your hop plants really need?

In general, hops in our region require 24-28 inches (651,696-760,312 gal/acre) of water per year and will require regular weekly irrigation supplementation to help combat moisture stress and continue healthy growth. In addition to the benefits on plant growth, regular watering can keep plants stress free and sometimes even reduce pest and insect pressure in your yard. Irrigation systems can help to alleviate some of the potential drought stress, but timing of water application is just as important as the amount of water hops are receiving. Hops require most of their water between training and flowering for optimal vegetative growth.

With variability in growing conditions and water loss through climatic conditions such as temperature, humidity, wind, and sun intensity there’s potential for significant water loss in any given growing season. We determined weekly irrigation requirements in each month of the growing season for one plant based on potential evapotranspiration (PET) rates in Burlington, VT (Table 1). To determine actual weekly irrigation amounts, weekly precipitation should be subtracted from the weekly irrigation.

Table 1: Weekly irrigation requirements for one plant by month

Month Gallons of water per week for one plant
May 15.62
June 18.52
July 19.79
August 16.63
September 10.79

Given these weekly rates, it is often best to apply water in split applications 2-3 days per week, every other day if possible, and be mindful of rain events throughout the week. Higher amounts may be needed for establishing a new yard. While irrigating with these given rates, you’ll be shooting for a little over 1/2” per acre (~14,000 gal/ac) of water from irrigation each week during bine and flower growth. While we are only able to deliver 3000 gal/ac at a time on the farm due to the constraints of our well, some water is better than none in any case.


What’s Hoppening with the Hoppers?

Posted: June 11th, 2018 by hoppenin


(Image: First, second, and third instar potato leafhopper nymphs.)

Potato leafhoppers (PLH) have arrived early this year and they were first spotted last week in Addison County hopyards.  As the information is as relevant now as it was last year, we are re-posting this hop blog. Knowing what to look for and having a management plan to combat these pests will help in preventing plant damage and decreases in yields.

Potato leafhoppers overwinter in southern states and are carried north with the spring wind currents. Depending on winter temperatures, these insects can arrive in the Northeast between late spring and mid-June. The warmer the winter, the further these insects will travel north. Leaf hopper populations typically peak around July 1 depending on when they arrive and then start dying down around the beginning of August. PLH management should continue over the next couple of months.

When scouting for leafhoppers, hop leaves should be turned over and observed. PLH are long and skinny and move from side to side. Adults are larger than their nymph counterparts and are winged. When searching for adult potato leafhoppers, leaves of the hops plants can be shaken and the adults will often fly away.

PLH may be confused with aphids which are much less active, are round in shape and are often found between the midrib and veins of the leaves. Not properly managing the leafhopper can cause significant damage in hop yards and dramatically reduce yields. The leafhoppers have piercing-sucking mouthparts that damage the leaf tissue and stem phloem of the plants. This feeding technique causes necrosis of the leaf known as hopperburn, where the tip and outer edges of the leaf to yellow and then brown. Hopperburn reduces the photosynthetic capacity of the plant and thus reduces the energy available to produce cones. That said, it is imperative that leafhoppers are managed in some way or another.

 For more information on PLH management in hops, see the following resources:

·         Potato Leafhopper in Northeastern Hopyards fact sheet.

·         Dr. Lily Calderwood recently reviewed management options as part of our Vermont Hops Power Hour webinar series.

·         Field Guide for Integrated Pest Management in Hops (https://www.usahops.org/resources/field-guide.html)

 Remember to keep calm and hop on…




(Image: Hopperburn: visual V-shaped chlorosis injury caused by potato leafhopper.)


2017 Hop Germplasm Study

Posted: June 7th, 2018 by hoppenin

While wild or naturalized hop plants are disbursed throughout the Northeast landscape, they have not been grown in this region on a commercial scale for the past 150 years.  Prohibition laws of the 1920’s, the spread of hop downy mildew, and the expansion of hop production in the Pacific Northwest led to the disappearance of the hop industry in the Northeast.  Recent and rapid growth in the craft beer industry has drastically increased the demand for local hop production.  The UVM Extension NWCS team is beginning to evaluate local wild cultivars to better understand their potential commercial value.

In fall of 2016, wild hop plants were gathered from eight locations in Massachusetts, New York, and Vermont.  A total of 10 wild hop species are being cultivated at Borderview hopyard.

Due to various growing conditions and hop characteristics, not all plants were harvested in 2017, and higher yields are expected in subsequent years!  Six varieties were harvested and data on total yield and quality were obtained – the characteristics between the hop varieties differed greatly in:

  • Susceptibility to pests
  • Reactions to pesticide combinations
  • Maturation rates
  • Oil profiles and oil compositions
  • Acid content

The UVM Extension NWCS team will continue to monitor these differences in future years, as well as obtain additional wild hop samples and varieties to add to the hop database.  Assessment of germplasm presents an opportunity to discover unique hop characteristics for a newly resurging Vermont crop.  Each variety’s characteristics could provide new and distinct flavor profiles for brewers through variable acid and oil profile combinations.  More information can be found in the full report on our Research page as well as hyperlinked below:



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