Biological control – utilizing a population of natural enemies to seasonally or permanently suppress pests – is not a new concept. The cottony cushion scale, which nearly destroyed the citrus industry of California, was controlled by an introduced predatory insect in the 1880s. Accelerated invasions by insects and spread of weedy non-native plants in the last century have increased the need for the use of biological control. Use of carefully chosen natural enemies has become a major tool for the...