In the last three years, two new causes, perhaps related, have been suggested. The immune systems of some populations of frogs and toads have somehow been damaged, perhaps by chemical contaminants, perhaps in combination with extremes of weather and temperature. And most recently Robert Stebbins, emeritus professor of zoology at University of California at Berkeley, has suggested that amphibian population declines may be caused by environmental pollutants that mimic estrogens and disrupt the endocrine and immune systems of amphibians. During the change from tadpole to frog, the creature stops eating, stressing its whole system. Of course no one knows what's really going on in nature.
Scientists produce fragments of information, then try to see patterns among the fragments.
Even if frogs ARE disappearing, we'll simply learn to live without them. All is well. These sprays, dusts, and aerosols are now applied almost universally to farms, gardens, forests and homes.