Biological control is the use by humans of beneficial insects such as predators and parasitoids, or pathogens such as fungi and viruses, to control unwanted insects, weeds, or diseases. Biological control dates back to 324 BC, when Chinese growers were recorded using ants to feed on citrus pests.
The State of New Jersey has long had the foresight to invest in biological control. Biological control offers tremendous social, environmental, as well as economic advantages. Biological control can become self-sustaining and integrated in the normal environment of the control area. Since such controls are expected to continue indefinitely, a high initial expense may prove to be a very low total cost. Biological control is particularly useful where chemical pesticides are not suitable or are impractical in environmentally sensitive areas, or on low-unit-value crops, such as alfalfa or soybeans, where complete control may not be required.
When pesticides were developed in the 1950’s, they were potent and relatively inexpensive. However, in 1962, the book “Silent Spring,” written by Rachel Carson, sounded a widespread warning about the persistence of certain pesticides in the environment and the environmental drawbacks of broad spectrum chemical use. Today’s modern pesticides are not as persistent as past pesticides and are important tools in crop protection. These pesticides can be very expensive, warranting an integrated approach to pest management, which compliments and promotes the use of biological controls.
In 1965, the President's Science Advisory Board concluded that for every $1 spent on biological control research and development, there were $30 in accrued benefits. In 1987, USDA calculated that nationally, biological controls against the alfalfa weevil netted savings of about $48 million annually; research costs were $1 million - for a ratio of return on investment of about 50 to 1. Currently, total grower savings from biological control amount to $2 billion, largely as a result of reduced cost of pesticide applications.
Eleven states currently maintain insect rearing laboratories for biological control: California, Colorado, Connecticut, Florida, Hawaii, Maryland, North Carolina, New Jersey, Oregon, South Carolina, and South Dakota. These facilities range greatly in size but carry out a wide variety of programs to control insect and weed pests of local or regional importance. The New Jersey Department of Agriculture’s Phillip Alampi Beneficial Insect Rearing Laboratory supplies or has supplied beneficial insects to support programs in many of the Northeast and Mid-Atlantic states.
There are three types of biological control, conservation, classical and augmentative. Most of what is done at PABIL falls under the category of classical biological control and involves finding and working with associated natural enemies of the pest. The New Jersey Department of Agriculture partners with federal and other state departments of agriculture and university researchers in developing biological control programs for weed and insect pests. These researchers travel abroad locate and collect natural enemies in a pest’s native area, which are maintained in a laboratory and evaluated for their effects on indigenous species of flora and/or fauna.
The natural predators and parasitoids must pass a rigorous quarantine process in federal facilities to ensure that no unwanted organisms (such as hyperparasitoids or microorganisms) are also introduced; and receive approval from the United States Department of Agriculture for introduction into the US. Only then do the beneficial insects come to the Phillip Alampi Beneficial Insect Rearing Laboratory for rearing. This process takes several years. Often when these beneficial insects come to the lab, they are relatively new to science, so a mass rearing protocol must be developed by the lab’s entomologists.
The beneficial insects are then reared in the laboratory or in field insectaries, ideally in large numbers, and released. Follow-up studies are conducted by the lab’s field crew to determine if the natural enemy successfully established at the site of release, and to assess the long-term benefit of its presence.
The choice of which beneficial insects can be used in a control program is limited to what insects are adaptable to a practical biological control program. Beneficial insects are not easily adaptable for biological control of every insect or weed pest infesting crops in New Jersey. The pest control program must also be compatible with current grower practices. A beneficial insect must have the ability to adjust to a new environment and, in the case of an augmentation approach, must lend itself to laboratory production.
The goal of biological control is to bring the pest population down below an economic threshold, not eradicate it. This process brings things into balance and allows native species to compete again. Classical biological control takes time. It will take a minimum of six to ten generations and possibly more before to evaluate the impact.