Scientists haven't been able to identify the cause of a crash in the stink bug population in the D.C. region last year.
Last year was a light one for stink bugs in this region, unlike previous years. But the invasive insects from Asia are poised to come back with a vengeance in 2013.
Farmer Bob Black saw significant damage to his orchard's crops due to stink bugs in 2011.
"One of our late varieties, Pink Lady — a lot of people like it, that's the latest apple — we had 50 percent damage on that," he told WAMU in 2011. "I can handle a few percent but it gets up to 25 percent, 50 percent, that's pretty devastating to me."
Stinkbugs did $37 million worth of damage in 2010 just to apples in Maryland, Virginia, Pennsylvania and West Virginia. In contrast, 2012 turns out not to have been that bad.
"We had growers that had problems late in the season but it wasn't the season long problems we had in 2010," said Tracy Leskey, a research entomologist with the U.S. Department of Agriculture.
There were two reasons for that. First, the early spring gave fruit crops a head start against the bugs. Second, the population of the bugs crashed in 2011, so there were fewer in 2012. But that's of limited comfort because nobody knows why the population crashed.
And they're back now, ready to come out in the spring.
"What was interesting in 2012 is those populations have essentially recovered and we're seeing populations that are six times larger than they were the previous year," he said.
Farmers have discovered pesticides that work. But stinkbugs can live on just about anything, which means hoards of them can swoop in at any time from a neighboring forest or weed patch 25 miles away. They remain one of the most serious agricultural pests in the region, entomologists say.