This efficacy was not detected by the post hoc analysis (F(3;6) = 8.36; P < 0.05, Fig. 1), but was obvious after pairwise comparison with the control (t-test with 6 df: P < 0.05). The insecticide was the only effective strategy for controlling

M. euphorbiae populations (F(3;6) = 1.63; P < 0.05). Finally, none of the strategies were effective for controlling M. persicae populations (F(3;6) = 0.59; P > 0.05). All strategies succeeded in reducing PVY spread (Fig. 2). Results suggest that oil effectively prevents PVY spread in the field and that it is significantly more efficient U0126 manufacturer than the elicitor and the insecticide (F(3;24) = 11.78; P < 0.001). Oil has an average efficacy of 26% in controlling PVY spread, compared with 14% and 10% for elicitor and insecticide, respectively. As expected, Karate Zeon® was effective in controlling

aphid populations except for M. persicae, the lack of efficacy in this case resulting from a selection of M. persicae clones that are probably resistant to the chemical. Many cases of M. persicae resistance to pyrethroids have been reported from all parts of Europe (Anstead et al. 2007). No aphicide effect was observed after treatment with the elicitor; hence, the insecticide effect of Bion® mentioned by Green (2009) was not confirmed by this experiment. The failure of rapeseed oil to control aphid populations contradicts previous studies (Martin et al. 2004; Martin-Lopez et al. 2006). However, this difference see more may be explained by the fact that those studies were not conducted under open field conditions. In our trial, the persistence of the product may have been reduced because of environmental factors. All treatments had a statistically significant effect on PVY spread. However, the efficacy of the elicitor (14%) and the insecticide (10%) was too low for them to be considered

suitable candidates for use in PVY control. This study showed the efficacy of the vegetable oil to be relatively MCE公司 low, 26%, compared with results obtained by Martin-Lopez et al. (2006), which showed 41% efficacy for refined rapeseed oil. In the same study, the efficacy of rapeseed oil was compared with the efficacy of mineral oil. Mineral oil proved much more effective, with 59% efficacy, similar to the 64% level of protection obtained by Boiteau and Singh (1982). We mentioned above that mineral oil can be phytotoxic; in practice, however, when the application procedures are properly followed, the risk of phytotoxicity is low (Boiteau and Singh 1982; Martin-Lopez et al. 2006). In summary, our study confirmed that there is no link between protection against apterae aphids and PVY spread, because alatae aphids are more important transmitters of PVY in the field than apterae. The elicitor strategy was found to be ineffective for controlling aphid populations and inadequate for controlling PVY spread.