Effect of phenolic acids from black currant, sour cherry and walnut on grain aphid (Sitobion avenae F.) development Grzegorz Chrzanowski * , Bogumi1 Leszczy  nski, Pawe1 Czerniewicz, Hubert Sytykiewicz, Henryk Matok, Robert Krzy _ zanowski, Cezary Sempruch Department of Biochemistry and Molecular Biology, Siedlce University of Natural Sciences and Humanities,12 Prusa St., 08-110 Siedlce, Poland article info Article history: Received 23 December 2010 Received in revised form 10 January 2012 Accepted 12 January 2012 Keywords: Biopesticides Glutathione S-transferase Peroxidase Polyphenol oxidase abstract The influence of naturally-occurring phenolic acid mixtures from selected plants was tested against the grain aphid (Sitobion avenae F.). Phenolic acids were extracted from the leaves of black currant (Ribes nigrum L.), sour cherry (Prunus cerasus L.) and walnut (Juglans regia L.), as well as from the green husks of walnut. The highest content of total phenolic acids and individual compounds such as p-hydroxybenzoic, p-coumaric, chlorogenic and vanillic acids were determined in J. regia. Ferulic and tannic acids were found only in J. regia. In laboratory bioassays, the phenolic acids extracted from plants prolonged the aphid prereproductive period by 1.5e3.0 days and reduced daily fecundity by 1e1.5 offspring. The strongest effects were observed after application of phenolic acids from the leaves and green husks of J. regia. The grain aphid used glutathione S-transferase (GST), peroxidase (POD) and polyphenol oxidase (PPO) in response to the application of plant phenolic acids. An increase in aphid GST activity was found in response to treatment with all extracts. Induction of PPO and POD was shown 24 h after the application of phenolic acids mixture from leaves of walnut; inhibition was observed after 48 and 168 h in response to treatment with both extracts of walnut. An inverse relationship between the POD and PPO activity of the aphids was found 24 h after application of the black currant and sour cherry phenolic acids. After 168 h, the activities of these enzymes were higher in treated aphids compared to unsprayed insects. Mixtures of phenolic acids naturally occurring in phenol-rich plants might be used as biopesticides to control the grain aphid as a part of an integrated pest management programme. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction The grain aphid (Sitobion avenae F.) is an important pest of cereals in Europe (Larsson, 2005). Aphids ingest phloem sap from sieve elements using their narrow piercing-sucking mouth- parts called stylets. While probing, the aphid stylets transiently puncture epidermal, mesophyll and parenchymal cells (Tjallingii and Esch, 1993). Aphids secrete various toxic compounds in their saliva (Karban and Agrawal, 2002) and are capable of inoculating the barley yellow dwarf viruses BYDV-MAV and BYDV-PAV (Brault et al., 2007). Pest management programmes in cereals rely on balanced fertilization and application of selective insecticides (Korbas et al., 2008). Joshi and Sharma (2008) demonstrated that imidacloprid is effective in controlling the grain aphid. This neonicotinoid insecti- cide has a mode of action connected with persistent activation of cholinergic receptors which leads to death (Jeschke and Nauen, 2008). However, possible adverse effects of imidacloprid include oncogenicity teratogenicity in rats, DNA damage and neurotoxicity (CDPR, 2011). Moreover, Johnson et al. (2010) described that major honey bee losses were attributable to organochlorine, carbamate, organophosphorous and pyrethroid pesticides exposure. Thus, efforts have investigated plant sources that contain natural bio- pesticides to control phytophagous insects (Cao et al., 2008; Kim and Kim, 2008; Pan et al., 2009). New biopesticides are also needed to combat the evolution of resistance to common pesticides (Copping and Duke, 2007). Leszczy nski et al. (1985) found that phenylpropenoid acids, pyrocatechol and hydroquinone reduced the feeding of Rhopalosi- phum padi (L.) on winter wheat (Triticum aestivum L.). Ciepiela and Chrzanowski (1999) ascertained a higher content of gallic, chloro- genic and caffeic acids within winter triticale cultivars which possessed a higher level of resistance to S. avenae. Moreover, Ciepiela and Chrzanowski (2001) showed the positive association between Abbreviations: GST, glutathione S-transferase; POD, peroxidase; PPO, poly- phenol oxidase; TCA, trichloroacetic acid; CDNB, 1-chloro-2,4-dinitrobenzene. * Corresponding author. Tel.: þ48 25 643 1223; fax: þ48 25 643 1367. E-mail addresses: grzegorzc@uph.edu.pl, gregorychrzanowski@yahoo.com (G. Chrzanowski). Contents lists available at SciVerse ScienceDirect Crop Protection journal homepage: www.elsevier.com/locate/cropro 0261-2194/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.cropro.2012.01.005 Crop Protection 35 (2012) 71e77