Ultimately, you can't control the natural enemy you unleash in an ecosystem. Biological control uses living organisms to reduce pest populations. Because biological control reduces pesticide use, is highly selective and self-perpetuating, there are several important advantages, as described below. In addition, an entire industry has been developed to produce, disseminate and aid in the adoption of natural enemies.
Despite the advantages, the use of biological control in ornamental crops in the United States and Europe is limited and is not increasing. These two approaches are fundamentally different from all other approaches to biological control because they are not intended to establish a population of natural enemies that multiplies to a level where it achieves long-term balance with the population of its hosts or prey. Nor are there effective biological control agents for scale insects that attack ornamental crops in the greenhouse or nursery. In addition, producers who must spend significant amounts on insecticide treatments to meet quarantine requirements are less likely to spend more money on biological control agents.
Biological control is used as an integral component of IPM programs in commercial ornamental production. Advances in the use of banking plants and new mechanical applicators for natural enemy release have the potential to make biological control even more self-perpetuating and economical. Finally, host plant effects, such as chemical defenses that are detrimental to natural enemies but to which the pest adapts, can reduce the effectiveness of biological control. Hundreds of biological control products are commercially available for dozens of invertebrate, vertebrate, weed, and plant pathogen pests (Anonymous 199. This program also led to the development of many concepts, principles, and procedures for implementing biological control programs.
The objective of an ecological approach to biological control of conservation is to modify the intensity and frequency of disturbances to the point where natural enemies can function effectively. A potential obstacle to biological pest control measures is that producers may prefer to stick to family use of pesticides. Natural enemies of insect pests, also known as biological control agents, include predators, parasitoids, pathogens, and competitors. However, while these natural enemies are often recommended, biological control will not necessarily prevent infestations on a significant scale, and there are no published research studies to support their use in ornamental production.
Colemani appears to be the most effective of the species available on the market, although there has been limited research on the biological control of aphids in ornamental crops. Biological control may also be a simpler option for producers facing increasing rules and regulations governing the use of pesticides. Insect predators and other arthropods are most commonly used in biological control because they feed on a smaller range of prey species, and because arthropod predators, with their shorter life cycles, can fluctuate in population density in response to changes in prey density.
