DNA Data Capture from Armored Scale Insect Specimens Intercepted in Plant Quarantine

Armored scale insects include many destructive pests of orchard crops, forestry, horticulture, and agriculture, costing an estimated two billion dollars per year in the US. They also have an extraordinary tendency to be invasive. As of 2005, the US had 132 species of armored scale insects introduced from other countries, comprising fully 40% of armored scale species in the US. Most of these (64%) were considered pests. About one new invasive diaspidid species is detected in the U.S. every year. The big problem is that armored scale insects are small, cryptic, and found on almost every kind of fruit and most other plant parts, so they are very prone to be transported unwittingly across borders. A second problem is that even once you find them, they are difficult to identify. They require expert preparation and study. Only adult females can be reliably identified and they need to be mounted on microscope slides. And the third problem is that, even once you get an identification, it may not be accurate. Some pests turn out to consist of complexes of species that can't be told apart without DNA evidence. For all of these reasons, armored scale insects are top candidates for developing a DNA-based system of identification. Here we propose to capture DNA sequences from armored scale insects intercepted at plant quarantine stations, while carefully identifying each specimen in the traditional way by mounting on a microscope slide. The results—DNA sequences from well-identified specimens—will help us develop a DNA-based system of identification, and also contribute to improving our understanding of the history and diversity of armored scale insects and their relationships with their host plants.