Integrated Pest Management

Integrated Pest Management (IPM) is an environmentally friendly, common sense approach to controlling pests. The IPM principles focus on pest prevention and selective use of pesticides. IPM relies on a four tiered implementation approach that hinges on proper pest identification and progress monitoring. Get started by obtaining the newest version of the Field Guide to Integrated Pest Management in Hops. This third edition includes pests from the Midwest and Eastern U.S. hop producing states. You may also want to obtain a copy of the American Phytopathology Compendium of Hop Diseases. 

Scouting Protocol -- By Jason Townsend
  • Develop a scouting program for your operation - make someone responsible

  • Scout each variety separately - they will differ in their susceptibility to the different pests

  • Create a map of your hop yard denoting varieties, surrounding topography, distance to woods, alfalfa fields, etc.

  • Scout on a regular basis - once a week minimum

  • Scouting a rea should be intensive to start, can be reduced over the years once you have a handle on pests and problem areas

  • Target 5-10% of the plants in a given block and randomize your approach (for example, scout 1 out of every 20 plants, making sure to cover all the hops varieties present in the yard)

  • Scouting from the ground to chest height is sufficient;  it is not necessary to cut down canopy leaves

  • Make sure to scout the undersides of leaves.  Many pests will be sheltering there and not on the leaf surface.

  • Develop a record keeping system that allows you to record information. Collect data and keep records in a central location - weather data, scouting records, spray records, soil and petiole test results, fertilization records

  • Always carry a notebook, pocket knife, magnifier, flagging tape, permanent marker, collection bags, and  camera

  • Flag problem areas in the field immediately and label the flags with date and observations.

  • Understand what a biotic factors can cause damage to hops, for example, the shredding of leaves that can result from high winds

  • Notice the unusual - do not go out looking for one specific thing


Sample scouting protocol - what to look for
 April - June
  • Infected spikes of downy mildew

  • Signs of powdery mildew on leaf surface

  • The first Potato Leafhopper adults.  If present, be ready to monitor for nymphs in coming weeks.  This species moves into New York on storm fronts from the south.  Adults have arrived as early as mid-June.  Infestations can be extremely damaging to first year plants

  • Two-spotted spider mites (unlikely to be present this early in the season, buy could be if pressure was severe in previous years)

  • Assorted Lepidoptera larvae like the eastern comma butterfly, hop merchant, hop vine borer and European corn borer.  These usually occur at low densities with minimal leaf damage.

  • Weed species present

  • Downy mildew - infected bines will cease growth and fall away from string.  Secondary spikes will form as side shoots become infected and these will have a similar appearance to the initial ground spikes of spring.  Angular lesions on the foliage will appear and are typically confined between leaf veins but these can be difficult to distinguish from other diseases.  Together these are signs of systemic infection which may require removal of plants.

  • Powdery mildew – distinctive white spots on leaves.  This disease has now been confirmed in New York and should be considered a zero tolerance disease, with diseased plants immediate removed and burned.

  • A number of late-season (starting in July) diseases have been identified in New York, including Alternaria, Botrytis, Fusarium, Leaf Spot (Phoma exigua), and Verticillium.  Often the symptoms of these diseases are overlapping.  Fungal spray programs throughout the season are essential in New York’s humid climate.

  • Also be aware of the viral diseases:  apple mosaic virus and hop stunt viroid.  These will leave plants with yellowish veins and stunted growth.  Virally infected plants must be removed from the hop yard.

  • Potato leafhopper nymphs – Look on the undersides of leaves to observe small, green, crab-like movement sideways across foliage.  5-10 nymphs per leaf represent a substantial infestation and could lead to photosynthetic decrease in plants.

  • Two-spotted spider mites – populations can grow rapidly in the hot dry weather of July, leading right up to harvest.  Western growers suggest a threshold for management action of 10 mites per leaf

  • Japanese Beetle populations are up and down annually but can be very damaging in bad years.  Pay particular attention to the canopy with this pest

  • Hop aphid - found primarily on undersides of leaves.  Similar size and color to Potato leafhopper nymphs but less mobile, more soft-bodied, usually present in greater numbers.

  • Be aware of fall webworm caterpillars which will occasionally form tents in hops foliage.  If detected, these should be immediately removed from the yard.  Other Lepidoptera larvae also appear in late summer, particularly hop merchant.  However, these rarely cause substantial damage.

  • Harvest

  • Be aware that two spotted spider mites and hops aphids are often most intense at or around harvest.  Be ready to monitor for these as you are harvesting.  Hops aphids in particular can continue to damage hops post-harvest if processing operations are not timely and efficient

  • Before harvest, make a summary of the pests and diseases experienced during the season:  timing, severity, control measures.  Comparing this with harvest records over the years can be a useful way to determine the effectiveness of your control measures.

During the 2014 and 2015 growing seasons, Cornell Cooperative Extension of Madison County hired a scout to scout a number of hopyards throughout Central New York. His findings are compiled in Scouting Reports available on the Cornell COoperative Extension of Madison COunty Website.  The University of Vermont also maintains a blog called "Whats Hoppening" that contains updated pest information. 


Scouting your own hopyard is a critical step for you to make good integrated pest management decisions. Steve created a scouting form to help you keep track of when you start seeing pest problems in your yard. Keeping track of this information for many years will 

Integrated Pest Management Resources

The Cornell Integrated Pest Management Guidelines for Hops provides information. It is available to purchase through the Cornell Bookstore. 

Washington State University published a comprehensive guide to all hops related pests. Here is the third edition. 

DEC Pestificide Certification

A good integrated pest management system involves the targeted use of pesticides and fungicides. For more information on how to become registered in New York State, check out the Department of Environmental Conservation's website

Information on the Tim Weigle grant

Link to Steve's scouting sheet. 

Northeast Hop Alliance (2019)


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