Biological Control of Aphids (and allies) as a Conservation Science
Biological control of aphids and other insect pests, weeds and pathogens achieves numerous conservation goals through benefits that protect biodiversity. Protection of biodiversity has been achieved via importation biological control through the successful biological control of invasive weed and insect species that have spread into natural areas. I will review some of these accomplishments and provide an example involving biological control of cottony cushion scale (a close relative of aphids) in the Galapagos Islands. Biological control can also lead to the reduction of pesticide use and therefore provides numerous environmental benefits. Some of these benefits, such as reduced toxic effects on wildlife, are well known, and I will provide one example from my own work on the soybean aphid that illustrates how the use of spray thresholds can be instrumental in harnessing biological control to protect endangered butterfly species from insecticide exposure. Beyond this though, reduced pesticide use results in lowered greenhouse gas emissions associated with manufacturing and applying pesticides, and I will provide an example of an estimate of the role of biological control in reducing greenhouse gas against the soybean aphid in the United States. Lastly, biological control can have a positive impact on agricultural yields and thus reduce the amount of land that needs to be converted to agriculture from natural forests or prairies. I provide an example of estimates of this type of benefit from recent successful biological control of the cassava mealybug (another close relative of aphids) in South-East Asia.