Invasive Species Update:
The Arizona Noxious Weed Program Serves the Citizens

Botanists sometimes stumble over a question on their Customs Declaration when returning to the US.—the one asking if you are carrying any plant material. You may be required to surrender, or eat, fresh fruits and vegetables to prevent the introduction of diseases or insects. Other plants are prohibited entry into the U.S. because they are listed on the Federal Noxious Weed list, maintained by the USDA Animal and Plant Health Inspection Service (APHIS). These are plants that pose a threat to agriculture, navigation, the environment, or public health in this country. In addition, each state maintains a noxious weed list, which includes plants that are threats to the environment or to agriculture in that state.

Noxious weeds are defined in terms of their effects on people, their activities, and their welfare. This is a social and legal definition, not a biological one, although listed plants typically share a suite of characteristics that we consider to be 'weedy'. These include establishing and growing rapidly on a variety of sites, often becoming dominant and persisting in an area.

The Arizona Noxious Weed list consists of three groups of plants. The most familiar, which all agriculture students see on a test at some time, are the Prohibited Plants. The Arizona Prohibited list currently includes 51 taxa, which may not enter or be sold in the state. In addition, seven plants are controlled to prevent spread as Regulated Noxious Weeds in Arizona, and sixteen plants are Restricted in the state, meaning that commodities or land may be quarantined to prevent further infestations. In extreme cases the Arizona Department of Agriculture can eradicate Restricted weeds and place a lien on the property.

Plants are designated noxious weeds when Arizona citizens feel that they have become, or are in the process of becoming, pests in the state. Based on the letters of concern he receives, the coordinator of the Arizona Noxious Weed Program recommends plants for listing. Dr. Frances (Ed) Northam is the new coordinator of the Arizona Noxious Weed Program. I had a delightful meeting with him earlier this spring about adding fountain grass (Pennisetum sitcom) and buffelgrass (Pennisetum ciliare) to the Noxious Weed list. Ed gave a very interesting talk on noxious weeds to the Pima Invasive Species Council in early June.

ANPS and its members have been instrumental in writing letters of concern about these exotic grasses in southern Arizona. Many members have described their observations of the spread of these species and their effects in the Sonoran Desert. This is extremely valuable information, as there is no formal monitoring of either these species. The knowledge and initiative of private citizens is the basis of the process of adding species to the state Noxious Weed list.

For more information about the state and federal programs:

Arizona Noxious Weed Program
Federal Noxious Weed list

Cindy Salo is completing her PhD at the University of Arizona with a study of red brome. She recently won a Fulbright scholarship to study in western Africa where she lived for two years as a Peace Corps volunteer.

The Plant Press Ed Note: In addition to these two grasses, the Department is now also considered adding Sahara mustard (Brassica tournefortica) and Malta starthistle (Centaurea melitensis) to the list.