Oil seed rape (Brassica napus L.) is one of the most commonly grown crops in Central Europe, and the brassica pod midge (Dasineura brassicae Winn.) is one of the most important pests there. Insecticides against this pest applied during flowering may harm bees and other beneficial insects. The use of biostimulants such as nitrophenolates, which are not harmful to beneficial insects, can be an environmentally friendly way to control this pest. Nitrophenolates activate lignin synthesis in rape pods so the brassica pod midge is not able to penetrate pods. Nitrophenolates also regulate the efficiency of the photosynthetic apparatus, thus increasing yield. For these reasons nitrophenolates were tested in field conditions in Central Europe in 2005, 2007 and 2008. Nitrophenolates were applied on 10-m2 plots, and their effect was compared to that of conventional insecticides. The number of damaged pods and yield parameters were assessed; the lignin content as well as photosynthetic rate was measured. Expression of genes related to lignin biosynthesis was examined in Arabidopsis thaliana L. The application of nitrophenolates decreased pod damage caused by the brassica pod midge. Expression levels of four genes related to lignin biosynthesis were increased after the application of nitrophenolates. The yield was higher in nitrophenolate-treated plots, which was attributed to an increase in the intensity of photosynthesis, higher chlorophyll content and improved chlorophyll a fluorescence parameters. The results showed that nitrophenolates have potential as a protective agent, but a further study is required. The application of nitrophenolates holds promise for reducing chemical input into the environment.