be seen growing over these willows so often that it was named the willow-wolf. The English word hop is derived from the Middle Dutch word , also meaning Humulus lupulus. Distribution and habitat The plant is native to Europe, western Asia and North America. It grows best in the latitude range of 38°–51° in full sun with moderate amounts of rainfall. Ecology The flowers attract butterflies, amongst other insects. Animal pests Damson hop aphid (Phorodon humuli) Two spotted spider mite (Tetranychus urticae) Japanese beetle (Popillia japonica) Comma butterfly (Polygonia c-album) Pale tussock moth (Calliteara pudibunda) Currant pug moth (Eupithecia assimilata) Buttoned snout moth (Hypena rostralis) Buff ermine moth (Spilosoma lutea) Diseases Downy mildew (Pseudoperonospora humuli) Powdery mildew (Podosphaera macularis) Toxicity H. lupulus can cause dermatitis to some who handle them. It is estimated that about 1 in 30 people are affected by this. Uses H. lupulus is first mentioned in 768 CE when King Pepin donated hops to a monastery in Paris. Cultivation was first recorded in 859 CE, in documents from a monastery in Freising, Germany. The chemical compounds found in H. lupulus are the main components in flavoring and bittering beer. The fragrant flower cones, known as hops, impart a bitter flavor and also have aromatic and preservative qualities. Some other compounds help with creating foam in beer. Chemicals such as linalool and aldehydes contribute to the flavor of beer. The main components of bitterness in beer are iso-alpha acids, with many other compounds contributing to beer's overall bitterness. Until the Middle Ages, many varieties of plant were used to flavor beer, including most commonly Myrica gale. H. lupulus became favored because it contains preserving agents which prolong the viability of a brew. Culture H. lupulus was voted the county flower of Kent in 2002 following a poll by the wild flora conservation charity Plantlife. References Bibliography "Czech hop varieties". Žatec: Chmelařský institut, 2012. on-line Barchet, Ron. "German hops in craft brewing". Wolnzach: Hopfen-Rundschau, 2014. Biendl, Martin. "Hops and health". Wolnzach: German Hop Museum, 2013. Hieronymus, Stan. "For the love of hops: The practical guide to aroma, bitterness and the culture of hops". Boulder, CO: Brewers Publications, a division of the Brewers Association, 2012. Kopp, Sylvia. "Barley & hops: The craft beer book". Berlin: Gestalten, 2014. Melnychuk, M. D.; Boyko, A. L.; Hryhoryuk, I. P.; Likhanov, A. F.; Klyuvadenko, A. A.; Martyn, H. H.; Kukovenko, V. I. "Hop