Effects of the insecticide phosmet on solitary bee foraging and nesting in orchards of Capitol Reef National Park, Utah.
Capitol Reef National Park, in southcentral Utah, contains 22 small orchards planted with antique fruit varieties by Mormon pioneers beginning over a century ago. The orchards continue to be managed in a pick-and-pay program, which includes spraying with phosmet to suppress codling moth (Cydia pomonella L.). The park is also home to a rich diversity of flowering plants, many of which are rare, bee-pollinated, and have populations within 1 km of the orchards. Over 3 yr, we studied the short-term effects of phosmet spraying on bee populations: (1) foraging on plants within the orchard understory and adjacent to it; and (2) nesting in, and at several distances from, the orchards. We recorded a rich bee fauna (47 taxa) in the orchards and on plants nearby. In 2 yr (2002 and 2004), we found no difference in the number of native bee visits to several species of plants flowering in and near to orchards immediately before and 1 d after spraying. Conversely, our nesting studies using the semidomesticated alfalfa leafcutting bee, Megachile rotundata (F.), showed strong significant declines in the number of adult males, nesting females, and progeny production subsequent to spraying at distances up to 160 m from sprayed orchards where the bees were presumably foraging. We showed that M. rotundata is negatively affected by phosmet spraying and suggest that caution should be exercised in its use in areas where bees are apt to forage.
Alston
Diane G
DG
Department of Biology, 5305 Old Main Hill, Utah State University, Logan, UT 84322-5305, USA. dianea@biology.usu.edu
Tepedino
Vincent J
VJ
Bradley
Brosi A
BA
Toler
Trent R
TR
Griswold
Terry L
TL
Messinger
Susanna M
SM
D000818:Animals; D001516:Bees / Q000187:drug effects*; D003247:Conservation of Natural Resources; D005247:Feeding Behavior / Q000187:drug effects*; D007306:Insecticides / Q000494:pharmacology*; D019684:Magnoliopsida; D009425:Nesting Behavior / Q000187:drug effects*; D010706:Phosmet / Q000633:toxicity*; D014589:Utah
D007306:Insecticides; D010706:Phosmet