for pesticide manufacturer bayer crop science, the issue is clear. >> most exrtrts agree that the single greatest threat to honeybee hltlth ishe v vara mite, annvnvasivblooood-ckingg pest th both h rectly rasitiz young d adult es and vectors bee diseases. where varroa mites are absent or well cocontrolled, honeybees are thriviving. >> but jim says he knows why his bees are dying. >> we had a multitude of neonics that were showing up in our bees. it doesn't take much to kill a bee. >> neonicicotinoids are a a relatively new class of insectcticide and coming o on te scene in the 1990s. it t is the fastest-growing group of insecticicides in ththe unitedd states. >> for the companies that make them, neonicotinoids, or neonics, are big business. they bring in over $2.6 billion a year in global sales. they are widely used as seed treatments, applied as soil drench, or sprayed onto foliage. in the u.s., they are used on some 200 m million acres of croplanand, on almomost a corn, canola, and half of all soybean crops, as well as many fruits and vegetables. >> they are used in home and garden pro