Adverse effects of soil applied insecticides on the predatory coccinellid Hippodamia undecimnotata (Coleoptera: Coccinellidae) Dimitrios P. Papachristos * , Panagiotis G. Milonas Department of Entomology, Benaki Phytopathological Institute, 8 Stefanou Delta, GR-14561 Kifissia, Athens, Greece article info Article history: Received 7 April 2008 Accepted 25 June 2008 Available online 3 July 2008 Keywords: Hippodamia undecimnotata Soil applied insecticides Carbofuran Imidacloprid Sublethal effects Development Fecundity Population parameters abstract We studied, under laboratory conditions, the possible effects of sublethal doses of two soil applied insec- ticides (carbofuran and imidacloprid) on development, survival and fecundity of the predator Hippodamia undecimnotata. For studies, predator fed upon Aphis fabae that was reared on Vicia faba plants treated with the systemic carbofuran and imidacloprid. Survival of immature stages in insecticides treatments (67.6% and 52.2%, for carbofuran and imidacloprid, respectively) was lower than control (77.4%). Both insecticides did not affect significantly total immature developmental time, while carbofuran caused a significant reduction of adult weight. Adult average longevity was significantly higher for the control than the insecticides treatments. Moreover, females oviposited fewer eggs in both insecticide treatments than the control (33% and 55% reduction in average fecundity for imidacloprid and carbofuran, respectively). Population increase parameters were also adversely affected by insecticides application. The importance of the adverse effect of sublethal doses of systemic insecticides on designing and management of insects’ pests are discussed. Ó 2008 Elsevier Inc. All rights reserved. 1. Introduction Coccinellids are important predators of aphids, coccids and spi- der mites (Iperti, 1999). However, their conservation in agroeco- systems is limited by the extensive use of insecticides. Predatory coccinellids are likely to be exposed to a great number of insecti- cides while foraging in the field. Coccinellid predators can be exposed to insecticides directly during pesticide applications or by contacting pesticide residues while foraging on sprayed surfaces. Moreover, predators may be affected indirectly by consuming prey exposed to insecticides. The direct contact effects of insecticides on coccinellid preda- tors have been studied extensively, as have a number of lethal (mortality) and sublethal (developmental time, fecundity, loco- motory behavior) effects on these predators (Olszak, 1999; Vincent et al., 2000; Youn et al., 2003; Lucas et al., 2004; Galvan et al., 2005; Bozsik, 2006). Soil applied systemic insecticides are generally absorbed by plant tissue and are therefore assumed to have few negative effects on insect predators (Pflüger and Schuck, 1991; Mizell and Sconyers, 1992; Ishaaya and Horowitz, 1998). Nevertheless, it is possible for a predator to acquire some sys- temic insecticides via their prey, as insecticides pass to plant tissues and via the plant sap pass to the herbivores. This may have a vital adverse impact on the population dynamics of a predator. Nhe adverse effects of systemic insecticides applied in soil have been studied mainly for heteropteran predators that supplement their diets with plant sap (Torres and Ruberson, 2004) and to some extent for other predators and parasitoids feeding on plant pollen and floral and extrafloral nectar (Smith and Krischik, 1999; Stapel et al., 2000). However, a possible ad- verse effect of systemic insecticides on predatory insects, within a tritrophic context, has not been studied so far. Carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl meth- ylcarbamate) is a broad spectrum systemic insecticide and nemati- cide. It widely used as an aerial or soil treatment against soil-dwelling and foliar feeding pests such as rootworms, wire- worms, weevils, beetles, flea beetles, leafhoppers and aphids of certain field and row crops, the most common including potatoes, corn, rice, sugarcane, soybeans and wheat (Trotter et al., 1991). Soil applied carbofuran is absorbed by roots and is transported via plant fluids to the aerial parts of the plants (Caro et al., 1976). Insects are affected by contacting or ingesting carbofuran that acts as a cholinesterase inhibitor. Imidacloprid is a systemic chloronicotinyl insecticide (1-[(6-chloropyridin-3-yl) methyl]-N-nitro-4, 5-dihydroimidazol- 2-amine) that enters pest through via ingestion or direct contact. It acts by disrupting nicotinic acetylcholine receptors in the insect nervous system (Mullins, 1993). It is worldwide used on ornamen- tals, field crops and vegetables with application to seeds, soil and foliage for controlling many pests including aphids, scales insects, white flies, some Coleoptera, some Lepidoptera and Diptera. After 1049-9644/$ - see front matter Ó 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.biocontrol.2008.06.009 * Corresponding author. Fax: +30 8077506. E-mail addresses: d.papachristos@bpi.gr, papmits@yahoo.ie (D.P. Papachristos). Biological Control 47 (2008) 77–81 Contents lists available at ScienceDirect Biological Control journal homepage: www.elsevier.com/locate/ybcon