IPC Programs
Projects & Resources
Encycloweedia: Prevention Program
The Noxious Weed Prevention and Control Program of the California Department of Food and Agriculture (CDFA)
Overview
California's pest prevention program addresses pests that are not native to the state. The program works under the assumption that it is more cost effective to keep pests out of California than to deal with potentially widespread and on-going infestations. The strategy for pest prevention is similar for all kinds of pests. There are four major parts: 1) keep a foreign pest from getting into California in the first place (called "exclusion"); 2) if a pest does get in, find it while the population is still small ("detection"); 3) when such a population is found, get rid of it so California is once again free of the pest ("eradication"); 4) and educate the public so they will understand the importance of keeping California free of new pests. CDFA also has some pest control functions, which help to reduce the impact of a pest if it escapes the pest prevention program and can no longer be removed from California.
CDFA's organization reflects the pest prevention strategy. Three branches deal directly with pest prevention: Pest Exclusion, Pest Detection/Emergency Projects, and Integrated Pest Control. The Pest Exclusion Branch handles all exclusion activities. The Integrated Pest Control Branch handles the detection, eradication, and control of weeds and vertebrate pests, and it runs control programs against some established pests. The Pest Detection/Emergency Projects Branch primarily handles detection and eradication programs against insects, other invertebrates, and some diseases. The Plant Pest Diagnostics Laboratory is another branch in CDFA and provides important support to field biologists in the other three branches and the County Agricultural Commissioner's (CAC) offices. The field biologists find an overwhelming variety of organisms in their search for foreign pests. They could not possibly recognize them all in the field, so they submit samples of suspicious organisms to the Laboratory, where specialists determine whether they are important pest species.
The Role of the Pest Exclusion Branch
Inspection staff from CDFA and the CACs cooperate in the efforts to keep foreign pests entirely out of California. They have the authority to enter any premises in the state to inspect plant material or related items. They may conduct surveys or investigations of any site liable to be infested with noxious weeds at any stage of development, in order to detect the presence of these pests.
The Secretary of CDFA may also establish quarantines against noxious weeds, with boundaries either at the State's borders or elsewhere within the State. For example, most Californians are familiar with the inspection stations on the highways near the borders.
CDFA inspectors also work at other locations where foreign pests are likely to enter the state. CDFA port biologists inspect domestic aircraft, and second port-of-call foreign and domestic vessels. Along with county agricultural inspectors, they also survey commercial nurseries for weed pests, examine plant material entering the State through parcel shipping facilities, and inspect rail freight shipments for incoming pest problems.
The Roles of the Integrated Pest Control Branch
The Integrated Pest Control Branch (IPC) has three major programs that directly involve the control of weeds: 1) the Weed and Vertebrate Program (Weed & Vert), 2) the Hydrilla Eradication Program, and 3) the Biological Control Program. Weed&Vert is largely focused on the detection and eradication of A-rated weed populations. The Hydrilla program is very similar except it is directed towards a specific water weed of special concern. The Biological Control program is a control program, whose scientists cooperate with others at the US Department of Agriculture and the University of California to re-unite foreign pests with their natural enemies, once the pests have become established in California.
Ten Biologists work in Weed&Vert across the state, organized into eight districts of four to nine counties each (see map), working closely with staff in the CAC Offices to detect and eradicate the weeds of concern in their districts.
IPC's major weed control problems do not sort themselves out evenly across the state. The majority of control projects are in the northeastern four counties, where Scotch thistle is a major target. The northern fourth of the state also has large populations of a variety of other A-rated weeds, including spotted knapweed, leafy spurge, musk thistle, Dalmatian toadflax, and squarrose knapweed. Dalmatian toadflax and spotted knapweed infestations are widely scattered across the northern half of the state. The central part of the Sierran foothills has a large infestation of skeletonweed, but the control efforts on that weed have moved to a containment strategy, to try to keep the weed out of uninfested counties. The number of species and the size of infestations taper off towards the south of the state, except for a major infestation of alligatorweed in Tulare/Kings and Los Angeles counties. A huge infestation of hydrilla existed in Imperial County in the 1980's, but the eradication effort there has reduced it to a handful of plants.
The Biological Control Program goes into action once a pest has escaped the prevention program and has become established in California. Four scientists work primarily on weed problems, four scientists work primarily on insect problems, and three staff and one manager provide support . Biological control of weeds is a painstaking, lengthy process involving several major steps. Many of the earliest steps are undertaken by other agencies, particularly the USDA or the University of California, but it falls to CDFA to help establish, spread, and evaluate the natural enemies once they are available. This involves rearing large numbers of natural enemies and releasing them in many different situations, to give them the best possible opportunity of becoming established. All this means that a biological control project on any weed requires a large amount of resources, and there are generally only enough resources to attack the most pressing problems. In recent years, the Program has focused most of its efforts on yellow starthistle, for which they have established five different natural enemies. Other recent efforts have focused on Russian thistle (tumbleweed), purple loosestrife, bull thistle, spotted knapweed, diffuse knapweed, and squarrose knapweed.