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ENTOMOLOGY

The Hop Plant

Contents
Home page
Management News
The Hop Plant
Hop Cultivation

Insect & Mite Pests
Black Vine Weevil
California Prionus
Hop Aphid
Twospotted Spider
Mite


Disease Pests
Downy Mildew
Powdery Mildew
Risk Forecaster
Other Diseases
Hop Crop Profile
Hop Research
Program Personnel
Hop Links
Disclaimer
Hop, Humulus lupulus L. (Urticales: Cannabaceae), is a perennial plant related to nettles and cannabis (hemp) that annually produces climbing stems from a perennial rootstock and crown. The bines (=vines) are produced in the spring and are densely covered with hooked hairs (trichomes) that help the bine climb. As the bine grows it winds around its support in a clockwise direction reaching length of 25 feet or more in a single growing season.

Hop is dioecious, producing male and female flowers on separate plants. The commercial hop is a female plant with flowers (burrs) produced on side arms that develop along the stem. Burrs develop into hop cones, which are sometimes called hops.

Fertile male plants are not tolerated in commercial hop yards as their pollen causes seeds to be produced reducing the brewing quality of the cones. The stem dies back to the crown after the hop flowers mature. Hop requires a period of winter rest or vernalization for optimum growth and flower production. A period of about 6 weeks with temperatures below 40° F (4.5° C) is needed meet this requirement. In the hop growing areas of the Pacific Northwest, this requirement is easily met.