Integrated pest management of flea beetles (Phyllotreta spp.) in spring oilseed rape (Brassica napus L.)

Abstract

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.