Dr. John Madsen (USDA-ARS Invasive Species and Pollinator Health, Davis, CA) just received the 2020 Outstanding Scientist Award from the Northeast Aquatic Plant Management Society. The letter of recognition says, among other things, "The Society recognizes you for your ongoing support of students, and your commitment, contributions and dedication to the field of aquatic plant management."

Dr. Madsen has participated in Weed RIC since 2014. He has developed a program studying phenology and management of waterhyacinth, Brazilian egeria, curlyleaf pondweed, and other species, concentrating mostly on the Sacramento-San Joaquin Delta.

In late October we made our monthly trip to sample curlyleaf pondweed in the Sacramento-San Joaquin Delta. On an island in the lower San Joaquin river, we spotted goats eating waterhyacinth (Eichhornia crassipes) and waterprimrose (Ludwigia sp.) along the shoreline. 

The goats were accompanied by a benevolent and protective llama, who showed no interest in the weeds.

Exotic water primroses (Ludwigia spp.) are aggressive invaders in both aquatic and riparian ecosystems. The plants form dense mats over the water surface. These mats constrain navigation and interfere with recreational activities, irrigation, drainage, and agricultural production. Rapid growth of these weeds also displace native plants and wildlife in aquatic ecosystems.

In the US, several exotic Ludwigia taxa have naturalized and become invasive: Ludwigia hexapetala, L. peploides subsp. peploides, L. peploides subsp. montevidensis, and L. grandiflora. Stakeholders are eager to get these weeds under control by all means necessary and one option is...

Arundo or giant reed (Arundo donax) is invasive in riparian areas in much of central and southern California, as well as other parts of the U.S. In the Sacramento-San Joaquin Delta, arundo grows on islands and along the edges of sloughs and canals. It is also common along the water's edge in the watersheds upstream of the Delta. This giant grass can grow to 20 ft tall or more and from a distance might be mistaken for corn. Arundo stems act like giant straws, wasting Delta water as the stems rapidly grow during the spring and summer. Dense mature patches of arundo block access to water, destabilize flood levees and constitute a fire hazard. For these reasons, the U.S. Army Corps of Engineers and various state and local agencies...