Pests of oil producing cabbage crops in the Eastern Forest-Steppe of Ukraine

Abstract

Today the major oil producing crops from the Brassicaceae family in the world and Ukraine are winter rape (Brassica napus oleifera bienis D. C.) and spring rape (Brassica napus oleifera annua Metzg.). At present the acreage of these crops in the world is over 40 million hectares, and in Ukraine there are more than 1 million hectares. Less common crops are white mustard (Sinapis alba L.) and Chinese mustard (Brassica juncea Gzem.). The world acreage under the mustard crops is about 3,0 million hectares (in Ukraine there are about 100 thousand hectares). Other oil producing crops from the cabbage family such as spring winter cress (Brassica campestris L.), winter rape (Brassica rapa oleifera DC), winter false flax (Camelina sativa subsp. pilosa N. Zinge), spring false flax (Camelina sativa var. Glabrata (DC.), oily radish (Raphanus sativus L. var. oleiformis Pers) and black mustard (Brassica nigra (L.) Koch) occupy only a small area, while the Abyssinian mustard (Crambe abyssinica Hosts. ex. RE Fr.) is not grown in our country at all. It is impossible to obtain high and stable yields of all agricultural crops without protection of plants from the harmful insects. The losses of the crops due to the pests are huge, especially during the mass reproduction of the insects. The entomocomplex of agroceonoses of oil producing cabbage crops is extremely rich and contains several hundred species. As a result of their vital functions more than 50% of the crops can be lost and as far as 25-55% growth increase in the yield can be reached due to the pollinating insects. Despite the short-term existence of agroceonoses of spring oil producing cabbage crops (90-120 days) their entomofauna is characterised by a considerable diversity of species composition. During the vegetation periods in 2007–2019 in the fields of the Educational, Research and Production Centre “Research Field” of Kharkiv National Agrarian University named after V.V. Dokuchaiev and the State Enterprise “Research Farm “Elitne” of the Institute of Plant Growing named after V.Ya. Yuriev of the National Academy of Agrarian Sciences of Ukraine we have found 54 species of specialised and multi-faceted pests of oil producing cabbage crops that belong to eight lines and 22 families. Among them 29 species are the specialised pests and 25 are multi-faceted ones. The frequency of the pest species occurrence on the crops is the following: eight species (15%) populate the crops on a mass scale, six species (11%) are moderately spread, and 40 species (74%) have a low population density. The cabbage bug, mustard bug, ground cabbage aphid, rose chafer, rape blossom beetle, mesographe flea beetle, flea beetle and diamond black moth belong to the species that populate the crops on a mass scale. Among them four species belong to the Coleoptera line, two species belong to the Hemiptera line, one species belong to the Homoptera line and one species belong to the Lepidoptera line. The representatives of the Coleoptera line dominate; their proportion in the entomological community structure is 48% (26 species). The economic importance of these pests is not the same and greatly depends on the population density and phenophase of the crop development as well as on weather conditions.