619 Biological Activity of Certain Oils in Control of Green Peach Aphid (Myzus persicae Sulz.) on Pepper V. Yankova, D. Markova and V. Todorova Maritsa Vegetable Crops Research Institute Plovdiv Bulgaria G. Velichkov Agriflor Ltd. Sofia Bulgaria Keywords: Myzus persicae, Capsicum annuum, mineral oils, essential oils, insecticides ibiological activity, plant protection Abstract Trials for biological activity establishment of certain mineral and essential oils applied alone or in combination for control to green peach aphid (Myzus persicae Sulz.) in pepper cultivar 'Stryama' grown in greenhouses were conducted. The chemical products Mospilan 20 SP 0.0125% and Karate max 0.025% are used for standards. High efficacy similar to those standards included in the study showed the combination Mospilan 20 SP 0.009%+ Akarzin 0.25% (efficacy over 90%), the mineral oil Akarzin 0.4% used alone, as well as essential oils Turpentine 1% and Eucalyptus oil 1% (efficacy over 80%). According to three way factorial analysis of variance it was established that the sources of the variation: variants of treatment (A), days after treatment (B), years of the study (C) and interaction between the applied variants and years of study (A x C) have a significant effect of the variability and efficacy. The power of the effect of the treated variants was pre-dominant (91.11%) while the power of the remaining considerable factors reached to 4.2% in total. Good efficacy demonstrated from these oils gives us another alternative possibility to control green peach aphid density in greenhouse pepper production. INTRODUCTION The pepper is one of the main vegetable crops grown in Bulgaria. Its fruits are used both for fresh consumption and for processing. Green peach aphid (Myzus persicae Sulz.) is an economically important pest on this crop. Aphids (Homoptera:Aphididae) occurred constantly in greenhouses and may create serious problems. Control on them is difficult due to their high reproductive ability and resistance to various insecticides. Besides direct damage that they cause at feeding they are vectors-carriers of dangerous virus diseases (Grigorov, 1980). Used chemical products are not always sufficiently effective and their frequent use result in negative secondary effects. The increased requirements towards the pepper quality produce enforce the application of alternative methods and products. The efficacy of different oils applied alone or combined with certain insecticides (imidacloprid and pirimicarb) is investigated for development of ecologically plant protection systems to M. persicae control. High mortality of М. persicae (over 80%) after treatment with mineral oil is established in separate oils application. Combined with low doses of imidacloprid and pirimicarb, the oils did not significantly increase the insecticides toxicity, but there was a decrease of the virus- infested plants from 40% to 60% compared to the plots treated with imidacloprid (Martin- Lopez et al., 2006). High insecticide activity against М. persicae is found in the application of raw soya oil and the raw rapeseed oil significantly reduced infected with Cucumber mosaic virus (CMV) plants (Martin еt al., 2004). It was establish that, essential oils from anise, fennel and basil have a toxic effect and reduce density of M. persicae (Digilio et al., 2008). Study on the insecticidal effect of different plant extracts, essential and mineral oils in relation with establishment of alternative means for control on green peach aphid in greenhouses was made (Loginova et al., 1993; Carrizo et al., 2004; Tansly and Conner, 2005). Mineral and essential oils enable to control M. persicae and limiting of virus- infected plants. This is an alternative opportunity to reduce chemical treatments with Proc. IV th Balkan Symp. on Vegetables and Potatoes Eds.: L. Krasteva and N. Panayotov Acta Hort. 830, ISHS 2009