A tiny bug called an aphid is gobbling up soybean fields in roughly half of Iowa’s counties now. The aphid was first detected in just a few northeastern counties in 2000 and has quickly spread west. Iowa State University entomologist Larry Pedigo is monitoring the pest.Professor Pedigo says there are a few ways to combat the soybean aphid, but one way is — other bugs. Lady Beetles are some of the natural enemies that’re helping hold the aphid populations in check.Pedigo says the aphid population has marched about 150 miles across Iowa in the past year, but it’s continued progress is questionable.Pedigo says the population may be declining so spraying may not be needed, since the chemicals can kill other beneficial insects. Iowa producers should begin harvesting soybeans in late September or early October and will get a better handle on damage then.The state’s worst damage reported from the aphid is in far northeastern Iowa’s Allamakee and Winneshiek counties. He says damage is even worse to soybean fields in parts of Wisconsin, Michigan and northern Illinois.