Effects of Pesticides and Fungicides Used on Grapevines on the Mealybug Predatory Beetle Nephus 'boschianus' (Coccinellidae, Scymnini)

  • V.M. Walton ARC lnfruitec-Nietvoorbij, Private Bag X5026, Stellenbosch, 7599, South Africa
  • K.L. Pringle Department of Entomology and Nematology, University of Stellenbosch, Private Bag Xl, 7602 Matieland (Stellenbosch), South Africa

Abstract

The effects of frequently used grapevine insecticides and fungicides on adults of the predatory beetle Nephus 'boschianus' of vine mealybug, Planococcus ficus (Signoret), were determined under laboratory conditions. When applied as cover sprays the pesticides chlorpyrifos, endosulfan, cypermethrin, chlorfenapyr and mercaptothion were very toxic to the predator, whilst the fungicides penconazole, fosetyl-Al, mancozeb and an insecticidal soap plus oil mixture were harmless. These results suggest that the insecticides may be harmful to a biological control system where N. 'boschianus' populations were dominant during the season. The three fungicides and the soap plus oil mixture, however, should be compatible with biological control by N. 'boschianus'.
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