Michigan hop crop report for the week of May 3, 2021

Hops are off to a solid start.

Cascade hop plant.
Cascade at earliest burn back in northwest Michigan on May 2, 2021. Photo by Aaron Martell.

Weather

Michigan’s 2020-2021 winter recap

December and January were very mild with much below average snowfall for most of the state. Feb. 4-21 were more typical with cold and snowy conditions. Temperatures in late March were above average before returning to more typical temperatures in mid-April. Above-average temperatures in late March accounted for most of the spring growing degree day (GDD) accumulation, which is currently above the five-year average for most growing regions across the state. However, current forecast projects suggest cool, below normal temperatures for the next several days.

Watch the most recent agricultural weather forecast from Michigan State University state climatologist Jeff Andresen.

May 3, 2021, weather summary for major hop producing regions of Michigan

Location

GDD 50 F (March 1-May 3)

GDD 50 F (March 1-May 3) 5-year average

Rainfall (inches) April 1-May 3

Historical rainfall (inches) average April 1-May 3

Southeast

 

Deerfield/Blissfield

244

148

2.23

3.61

Southwest

 

Benton Harbor (SWMREC)

236

159

1.22

4.11

Berrien Springs

238

151

1.57

3.52

Lawton

236

147

1.36

3.89

South central

 

Hickory Corners

233

130

1.09

4.17

Kalamazoo

239

139

1.58

4.41

East central

 

 Flint

235

127

1.52

3.84

East Lansing (MSU Hort)

223

128

1.53

3.56

West central

 

Ludington

149

73

2.16

3.19

Northwest

 

Petoskey

106

20

2.65

4.00

Traverse City (NWMHRC)

102

60

2.87

2.58

Northport

68

28

1.61

1.72

Williamsburg

119

41

0.98

2.86

Northeast

 

Hawks

93

40

1.98

3.00

Stage of production/physiology

Hops across Michigan are in principal growth stage 1: leaf development (see chart below). Growers are stringing or have completed stringing. Irrigation systems, at least in the southern areas of lower Michigan, are coming back on-line. Most growers who prune did so across the state between April 18- 25, though some may have pruned earlier due to the unseasonably warm temperatures in early April. Unpruned yards in west central Michigan have up to 4 feet of growth.

Average Michigan hop growth stage chart.
Average Michigan hop growth stage based on date. Botanical drawings courtesy of Dodds, Kevin. 2017. Hops, a guide for new growers. NSW Department of Primary Industries.
Timing of hop production chart.
Timing of hop production management activities in northwest Michigan.

Hop growth stage chart.

Crop development

Southeast

Mechanical pruning was done April 18-19 when shoots were 4-6 inches. As of May 3, shoots are 3-4 inches tall.

Hopyard in snow.
Southeast Michigan, April 20, 2021. Photo by Rose Stahl.

Southwest

Some frost damage, growing out of it now, with no major issues. Shoots are 6-10 inches. Chemical pruning was done the end of April-first week in May. There are some downy mildew spikes.

Hopyard.
Southwest Michigan hopyard in late April. Photo by Mike Reinke, MSU Extension.

West central

Some frost damage, unpruned shoots up to 4 feet.

East central

In East Lansing, Michigan, there is some frost damage, but hops are pushing through. No disease yet.

Northwest

In Northport, Michigan, hops were pruned April 23 and shoots are currently 6 inches. In Williamsburg, Michigan, hops were pruned the second week of April or so depending upon cultivar. Shoots are currently 4-10 inches.

Centennial hops.
Centennial in northwest Michigan, May 2, 2021, with annual ryegrass cover crop in the alley. Photo by Aaron Martell.
Triumph hops.
Second year Triumph in northwest Michigan, May 2, 2021. Photo by Aaron Martell.

Northeast

Hops were pruned on April 25, and shoots are currently 2 inches.

Weeds

Growers who applied preemergent did so in late March- early April. The window for early season, non-selective herbicides is now completely closed. It was a narrow window again this year and broadleaf weeds may be an issue this season. Grass weeds are taking off and need to be treated when small for optimal control. 

Diseases

Currently, there have been no reports of flagged shoots caused by powdery mildew in the state. However, reports of downy mildew spikes have been observed at various locations throughout the state but due to the dry weather limited sporulation was observed. Over the next few weeks, expect downy mildew symptoms to become more apparent in yards.

Downy mildew is a serious disease in Michigan and affects cones, and foliage and can become systemic; in extreme cases, the crown may die. Cool and damp weather during the spring provide ideal growth conditions for the pathogen. The causal agent of downy mildew, Pseudoperonospora humuli, overwinters in dormant buds or crowns and can emerge on infected shoots in early spring, resulting in basal spikes. The hop spike usually appears yellow and stunted in the spring with spore masses on leaf tissue. Sometimes spikes can be misidentified as frost damage from previous weeks (see photos below).

Once herbicide burndowns have been completed for the season, growers may wish to begin a drench or banding treatment for downy mildew using effective chemistries (Ridomil Gold SL, FRAC 4). Other effective foliar fungicides include fungicides in FRAC codes 4, 11, 21, 40, 43, 45 and 49. See the MSU Extension article, “Managing hop downy mildew in Michigan,” for more information on management methods for downy mildew, and refer to the Michigan Hop Management Guide.

Downy mildew spike on hop plant.
Downy mildew spike on Nugget from a previous growing season. Notice the dark sporulation on the underside of the leaf tissue. Photo by Tim Miles, MSU.
Frost damage on hop crops.
Left, Centennial frost damage in East Lansing, Michigan, on April 26, 2021. Right, Nugget frost damage in East Lansing, Michigan, on May 3, 2021. Photos by Tim Miles, MSU.

Insects

No significant insect pest observations this week.

Fertility

Most growers using granular fertilizers have already applied them or are planning to apply them soon. As a reminder, please reference the Nutrient Management section (pages 22-26) of the Michigan Hop Management Guide for fertility recommendations. Also, MSU recommends submitting soil samples each spring around the same time. Please refer to lab sampling and submission instructions prior to sending in samples.

Soil testing labs

Comprehensive soil health testing labs

Stay connected

For more information on hop production, visit the MSU Extension Hops website. Also, Michigan State University Extension is hosting a series of interactive Hop Chat Zoom meetings this 2021 season to allow easy communication between producers and MSU faculty. These informal weekly sessions run every Wednesday at noon from May 4 through Sept. 7 and include crop and pest updates from MSU Extension’s Rob Sirrine and Erin Lizotte. In addition, MSU faculty will drop in to address timely issues and provide research project updates. Bring your field notes, too! We want to hear what’s going on in your hopyard. Registration is free but required. Sessions will not be recorded. Register here!

This material is based upon work supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under Agreement No. 2017-70006-27175. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

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