Stinknet: a Weed Advancing in Arizona

University of Arizona Cooperative Extension Gila County presents: Garden and Country Extension Webinar Series. A Zoom webinar (60-minutes or less) featuring a variety of horticultural and natural resource topics relevant to the environmental conditions and residential concerns of Gila County, Arizona.

Featured Topic: Stinknet: a Weed Advancing in Arizona

Featured Speaker: Michael Chamberland, Assistant Agent, University of Arizona Maricopa County Cooperative Extension. Michael serves as the Assistant Agent for Urban Horticulture with the University of Arizona Maricopa County Cooperative Extension. He works with Urban Horticulture, which includes overseeing the Maricopa County Master Gardener Program and plant problem diagnostic work, especially for the commercial horticulture industry. Agent Chamberland has considerable experience with curation and management of living collections at botanical gardens, including the Desert Botanical Garden, Tucson Botanical Gardens, and the U.S. National Arboretum in Washington DC. His prior work with University herbaria has engaged Michael with many aspects of native and introduced plants in Arizona.

Webinar Overview: Stinknet, also known as globe chamomile (Oncosiphon pilulifer), is a relatively new weed in Arizona that has quickly spread. The first herbarium collection for Arizona was made in 1997, and by 2019 the plant had risen to public attention due to its conspicuous presence. It is spreading along the I-10 corridor, becoming well established in Maricopa, Pinal and Pima Counties. The movement of people and vehicles through seed-laden stinknet infested areas has potential to dislodge seeds and may be a significant factor in its spread. Stinknet is a nonnative cool-season annual member of the sunflower family (Asteraceae). It may degrade rangeland as it crowds out other desirable cool-season plants. Stinknet is reported to be unpalatable to livestock, and shows little sign of damage by herbivory. It has been implicated in cases of respiratory distress, and there have been reports of contact dermatitis from skin exposure. Stinknet forms thick drifts of plants that are a particular problem for wildfire in Sonoran Desert vegetation. It dries and dies as Arizona enters its hot dry early summer, which is also wildfire season. It can then can catch and spread fire from an initial ignition source and carry flames from shrub to shrub and tree to tree. Combatting stinknet, especially larger infestations, and those in wildland situations, will require a long-term integrated weed management plan. Early detection of spot infestations and rapid response to pull and bag weeds before a seed reserve can build is key to preventing the spread of stinknet into new areas like Gila County. Agent Chamberland authored the following Extension bulletin on the subject: https://extension.arizona.edu/pubs/stinknet-weed-advancing-southern-arizona

Webinar Facilitator: Chris Jones, Extension Agent, University of Arizona Gila County Cooperative Extension

Zoom Link: https://arizona.zoom.us/j/83165523853 Please log in up to 10 minutes prior to the webinar.