Project Overview

Reports

Commodities

Target Pests

Practices

The Western Invasive Plant Risk Evaluation Network (The Network) is an interstate work group established in 2021 that has been sustained continuously through 2024 with grant support from the Western Integrated Pest Management Center (WIPMC). The Network brings together partners from Washington, Oregon, California, Nevada, and Arizona to assess non-native plant species that may pose a risk of becoming invasive and to communicate about early detections. Partners range in how they use the assessment results, including as an initial evaluation for their formal state assessments or to inform landscaping guidelines.
The Network supports several WIPMC priorities and has become an excellent platform for addressing prevention and facilitating regional IPM communications. In 2025, Cal-IPC proposes to expand the Network’s scope to include outreach to university extension Master Gardeners (MGs), who provide a powerful linkage with the public on matters involving plants in urban communities. They have previously invited Cal-IPC to present on invasive plants, and Network partners in other states also report a similar interest from their local MGs. As adding MGs to the Network will further broaden our collective reach, proposed in 2025 is the development of two online MG workshops. To promote IPM for a range of audiences, Cal-IPC will lead direct outreach efforts to encourage workshop attendance by individuals supporting underserved communities, including those from the Yurok and Karuk tribes of northern California. The workshops will provide information on horticultural invasive plants and background on risk assessments.
For conducting risk assessments, the Network uses the online Plant Risk Evaluator (PRE) tool. PRE was developed by UC Davis and the University of Washington in 2015 as part of PlantRight, a project which is dedicated to reducing horticultural introductions of invasive plants. Since 2020, Cal-IPC has worked with PlantRight and WIPMC funding to maintain PRE, working with UC Davis web designers to rebuild it on a new web platform and securing external funding to update the climate matching tool in PRE.
Cal-IPC’s efforts to support the PRE tool and expand its use strengthen prevention as a key component of IPM. PRE’s regionally specific risk evaluations are especially valuable because many plants have a lag phase before becoming invasive and because invasiveness varies across environments. The Network improves prevention by serving as an early detection communication network supporting these evaluations, and, with WIPMC support, will reach the general public more effectively through MGs and a new publicly accessible PRE website.
For 2025, we are requesting funding to continue the work of the Network to: (1) facilitate evaluation of at least 18 plant species for Washington, Oregon, California, Nevada, and Arizona; (2) train additional PRE evaluators and horticultural reviewers for partner states; (3) engage MG groups with Partners across five states through workshops that support their efforts to educate community members; (4) make PRE’s database of evaluations accessible to the general public. Together, these efforts will strengthen invasive plant prevention efforts and IPM in the Network and beyond.

Objective 1. Conduct risk assessments – We will work with partners from each state to generate and finalize another 18 assessments of plant species (2-3 for each partner state and up to 10 for California). The number is reduced from last year because of partner state capacity issues, lower urgency with highest priority species having been already evaluated, and our addition of Master Gardener training. 90% likelihood of success by 2/28/2026.
Objective 2. Strengthen PRE assessment and review capacity – We will work to strengthen invasive plant risk assessment capacity across five partner states (California, Arizona, Nevada, Oregon, and Washington) by offering refresher training, as well as project management, QA/QC, evaluation reviews, logistical support and timeline management to all partners using PRE. We will also solicit involvement from botanically trained MGs. Cal-IPC will train a minimum of three new PRE evaluators and two horticultural reviewers. 90% likelihood of success by 12/31/2025.
Objective 3. Train Master Gardeners – We will develop and lead training with interstate partners and MG leads and conduct at least two 2-hour workshops (one for northern states and one for southern states) on invasive plants and horticulture. 90% likelihood of success by 12/31/2025.
Objective 4. Share knowledge – We will make completed PRE assessments public on the new PRE website and promote their availability to MGs and our respective stakeholder communities through at least one email blast, one newsletter article, and one conference presentation that highlights the project. We will also maintain the web tool. 95% likelihood of success by 12/31/2025.