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This study examines the impact of imidacloprid, a systemic insecticide, on bees. It explores the toxicity levels of neonicotinoid insecticides and their consequences on both bees and beneficial insects. The research also investigates the residue levels of imidacloprid in various plants and different treatment methods. The study provides important insights into the potential threats posed to bees by these insecticides.
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Krischik U of M, 2012 MN Honey Producers Meeting, Duluth, MN “Do Label Rates of Imidacloprid Result in Residues in Flowers that Kill Bees?”
Systemic insecticides Systemic Organophosphates aldicarb (Temik), oxamyl (Vydate), dimethoate (Cygon) Neonicotinyl imidacloprid (Marathon, Merit), clothianidin, thiamethoxam, dinotefuran Novel mode of action pymetrozine (Endeavor) Translaminar, or local, systemic activity Microbial- abamectin (Avid) IGR- pyriproxyfen (Distance) PR- chlorfenapyr (Pylon) SP-spinosad (Conserve) OP- acephate (Orthene) C-Carbofuran (Furadan)
Threats to bees: soybean aphid management Organophosphates + Pyrethroids, are very toxic to bees. • Dimethoate is highly toxic, LD50 15 ng/bee • Chlorpyrifos is toxic, LD50 70 ng/bee • Methyl parathion is highly toxic, LD50 11 ng/bee • Coumaphos is 180 times less than methyl parathion, with LD50 of 2030 ng/ bee • Esfenvalerate is highly toxic, LD50 15 ng/bee • Cyfluthrin is highly toxic, LD50 37ng/bee • Zeta-cypermethrin is extremely toxic, LD50 2 ng/bee • Lambda cyhalothrin is highly toxic, LD50 38 ng/bee • Permethrin is extremely toxic, LD50 8 ng/bee
Since 1990, neonicotinoids and pyrethroids replaced organophosphates (OP) • Application: Seed treatment (Gaucho), granular or drench treatment into soil (Merit), soil injection (Merit), trunk injection (Ima-Jet). • Systemic, from roots throughout plant to nectar and pollen (Merit, Admire, Marathon). • Moves less thru a plant when applied to leaves (Provado)
Case study: neonicotinyl consequences on bees Commonly used neonics are very toxic to bees. • Thiamethoxam (seed treatment)oral, highly toxic 30 ng/bee • Clothianidin (metabolite thiamethoxam) (seed treatment)oral, highly toxic 22 ng/bee • Imidacloprid (granular, seed treatment)oral, highly toxic ng/bee 18 ng/bee • Dinotefuran (granular)oral, highly toxic ng/bee 75 ng/bee
Case study: neonicotinyl consequences on bees Not as toxic to bees. • Acetamipridcontact, moderately toxic 7.1 microg/bee • Thiaclopridoral, slightly toxic 14.6 microg/bee
Water solubility: Neonicotinyl insecticides dinotefuran is 80 times more water soluble than imidacloprid emamectin benzoate has very low mobility (KOC) and long duration
Linden trees: Imidacloprid applied to linden to kill adult JB, but linden is a favorite bee plant
Beneficial Insects: Flowers provide food for adults. Larvae kill pests Adults Larvae Adults Larvae
Gaucho (imidacloprid-seed treatment) banned in France from 1999-2008
Neonicotinyl insecticides banned in Germany May 2008 see recent research Marzaro 2011, Kruke 2012, Tapparo 2012 • German Federal Office of Consumer Protection and Food Safety (BVL) suspended registration of seed treatment used in canola and corn. • Suspended are:Antarc (imidacloprid),Chinook (imidacloprid),Cruiser (thiamethoxam),Elado (clothianidin),Faibel (imidacloprid),Poncho (clothianidin). • 2010 April/May at Purdue, Indiana, data captured,
2011 Imidacloprid residue plants penick.net
Whitney Cranshaw, Colorado State University, Lacy L. Hyche, Auburn University, www.forestryimages.org Efficacy and duration imidacloprid in field grown poplars at 12 mo • Cottonwood leaf beetle, Chrysomela scripta (Coleoptera: Chrysomelidae) • 4 generations occur in MN, >8 in southern US. • Adults overwinter under bark and leaf litter.
Efficacy and duration imidacloprid in field grown poplars at 12 mo
Efficacy and duration of imidacloprid in container grown poplarsat 12 mo
Efficacy and duration of imidacloprid in container grown poplarsat 12 mo
Efficacy and duration imidacloprid in container grown rose at 12 mo Japanese beetle adult (Coleoptera: Scarabidae) Adults feed on foliage Grubs feed on grass roots Rose ‘Mr. Lincoln’
Relationship of imidacloprid applied to soil and imidacloprid translocate to canola pollen April May July (2 treatments on plot April and July) August no insecticide 2500 2072 imidacloprid in pollen (ppb) 2000 162 1500 1000 461 342 341 500 313 179 24 15 5 13 7 8 0 0 0 0 0 0 0 0 4 8 80 160 imidacloprid in soil (mg)
Relationship of imidacloprid applied to soil and imidaclopridresidue in soil (ppb) July soil August soil no treatment 3913 5000 4500 4000 3500 3000 1816 imidacloprid in soil (ppb) 2500 1318 1555 2000 1500 743 1000 518 500 199 258 77 51 4 4 0 0 4 8 80 160 Gaucho Gaucho Poncho imidacloprid in soil (mg)
Imidacloprid residue in nectar • Gaucho seed treatments: Imidacloprid in nectar • 1.9 ppb in sunflower nectar (Schmuck et al. 2001) • 0.6-.8 ppb in canola nectar (Scott-Dupree+Spivak 2001) • Imidacloprid soil treatments: Imidacloprid in nectar • 3-10 ppb in purple tansy nectar (Wallner et al. 1999) • 15 ppb (1X) and 27 ppb (2X) buckwheat nectar (Krischik et al. 2007) • 26 ppb (27d), 12 ppb (38d), 9 ppb (63d), reapplied 53 ppb (21d) in tropical milkweed
Imidacloprid residue in nectar • Marathon applied to containers in the greenhouse results in higher concentrations of imidacloprid in nectar compared to Gaucho: 15 ppb vs. 1.9 ppb (Schmuck et al. 2001). • Beneficial insects in the foraging environment may be exposed to imidacloprid in nectar from a range of sources. • Other systemic neonicotinyls, such as acetamiprid, dinotefuran, clothianidin and thiamethoxam are also being used, and may kill beneficials.
Imidacloprid translocation to nectar • Gaucho treated-seed: Imidacloprid in nectar • 1.9 ppb in sunflower nectar (Schmuck et al. 2001) • 0.6-.8 ppb in canola nectar (Scott-Dupree+Spivak 2001) • Imidacloprid soil treatments: Imidacloprid in nectar • 3-10 ppb in purple tansy nectar (Wallner et al. 1999) • 15 ppb (1X) and 27 ppb (2X) buckwheat nectar(Krischik et al. 2007)