One of the most dangerous pests of cabbage crops which can damage plants in the budding and flowering phases in all areas of their cultivation is a rape blossom beetle (Meligethes aeneus Fabricius, 1775). The pest is widespread throughout Ukraine; it causes significant damage to the crops every year and reduces the seed yields. It should be noted that the rape blossom beetle is not new to our country and as a pest of rape and other crops from the cabbage family has been mentioned since 1845, and a detailed description of its morphology, biology and ecology can be found in the works of the nineteenth century. It is established that in the Eastern Forest-Steppe of Ukraine the first individuals of the rape blossom beetle appear on the flowering wild growing plants (first of all on dandelion and buttercup) when the average daily temperature exceeds 8 °C, it is the middle of the first decade of April and the beginning of the third decade of April. The mass emergence of the rape blossom beetles takes place when the daily average temperatures are at the range of 9–13 °C and the sum of the effective temperatures above 5 °C is at the range of 100–113 °C, it is the middle of the second decade of April and the end of the third decade of April. The females of the rape blossom beetle usually lay 2–3 eggs into one bud of spring rape or mustard. When protecting the crops from the rape blossom beetle the highest technical efficiency was noted when applying the binary mixture of the microbiological preparation Actophyte, 0.25 % of emulsion concentrate in the dose of 4.8 L/ha and systemic insecticide Biscaya, 24 % of oily dispersion (0.25 L/ha) and in 14 days after spraying it was 76.6 % on white mustard, 74.3 % on Chinese mustard and 76.2 % on spring rape. The highest growth increase in the yield capacity was observed in the same variant; for white mustard it was 0.431 t/ha, for Chinese mustard it was 0.265 t/ha and for spring rape the growth increase amounted to 0.277 t/ha. As a result of the researches it is established that the weight of 1000 healthy seeds is 2,6996 g, and the weight of the seeds damaged by the larvae of the rape blossom beetle is 0.4213 g, so it is reduced by 84.4 %. The filling of the damaged seeds is 6.8 times more, which indicates that they are smaller in diameter and frail. The undamaged seeds of spring rape contain 35.92 % of fat, and the damaged seeds contain only 17.48 %, which is 2.05 times less. The protein content in the undamaged seeds was 30.97 % and in the damaged ones it was 32.23 %, that is 1.04 times more. The germination rate of the undamaged seeds of spring rape under the laboratory conditions on the eighth day was 90.0 %, and the germination rate of the damaged ones amounted to 58.0 % and was lower by 32.0 %.

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One of the most dangerous pests of rape is a complex of the undulating flea beetles that can do harm to the plants from the phase of sprouting and until the harvest ripening. According to our research, all six species of the undulating flea beetles are spread in the Eastern Forest–Steppe of Ukraine. The most numerous species are Phyllotreta atra F. (about 71%) and Phyllotreta nigripes F., the latter is less numerous (about 16%). The rest 4 species make up from 0.4 to 8.8% in the population structure. The damage of spring rape sprouts caused by the leaf beetles both against the background with the fertilizers (N30P30K30) and against the background without the fertilizers significantly affects a weight of 1000 seeds. Against the background without the fertilizers it is a little less and R²=0.875 while against the background with the fertilizers R²=0.9986. The yield capacity of spring rape both against the background with the fertilizers (N30P30K30) and against the background without the fertilizers depends on the degree of the sprouts damaged by the leaf–eating pests largely. It is a little higher against the background without the fertilizers and R²=0.9995 while against the background with the fertilizers R²=0.9911. The presowing toxicity of spring rapeseeds with the subsequent spraying of the crops in the phase of sprouting, namely the toxicity of two pairs of true leaves, provides a reduction in the density of the undulating flea beetles population 7.5–10.0 times below the level of the economic threshold of harmfulness. The best field germination of rape seeds both against the background without the fertilizers and against the background with the fertilizers is noted. The applied insecticide and fungicide seed treatment agents have a negative affect on the laboratory germination of spring rape seed material. The worst indices of germination were noted in the variants when applying Royal FLO, 48% of water and suspension concentrate in the dose 5.0 L/t and Royal FLO, 48% of water and suspension concentrate+Taboo, 50% of suspension concentrate in the dose of 5.0+6.0 L/t and on the 9th day these indices were 77.0% and 76.5% respectively.