Image of the Day: Its Droppings Give it Away

Asian longhorned beetles might have eluded their last scientist. Researchers have developed a genetic fingerprinting technique for tracking and identifying the invasive insect's excrement.

The new technique, developed by USDA Agricultural Research Service scientists Wayne Hunter and Michael Smith, quickly screens droppings on trees known to attract the pest. If a sample matches the beetle's fingerprint, scientists will know they have a potential infestation on their hands.

The beetles are one of the country's "most wanted" invasives for two reasons. First, it chomps on hardwoods--such as maple, elm, and birch--which puts forests and tree-lined neighborhoods in danger.

Second, it's a sneaky killer. The beetle inflicts its greatest damage while hidden deep inside trees. Immature Asian longhorned beetles create elaborate tunnels while feeding on the interior, which weakens the trees until they snap in half or need to be cut down.

Smith has also found a weapon for controlling the alien insect--an insecticide, already in use against other pests, that is nearly 100 percent effective against the beetles in just minutes.

Currently, crews must climb trees one by one and scrutinize the bark for the faintest signs of invasive beetle activity, but the crews could use the pesticide as a quicker-acting detector--they would simply spray trees they suspect are infested and wait to see if the pest falls from it.

--Bjorn Carey

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Credit: Michael Smith