## 4 Discussion
Therefore, the effectiveness of the control depends largely on the technical side of the treatment; in accordance with the recommendations of the acaricide manufacturer, for it to work effectively, both the dose of water (400 1 ha\({}^{-1}\)) and the preparation (1.5-1.8 l ha\({}^{-1}\)) should not be reduced. These methods are compatible with the EU strategy and the IPM directive. In our research, we used preparations that are registered for the control of spider mites in orchards, ornamental plants and do not have label extension for field plants, specifically sugar beet. Recently, many studies have been carried out on replacing synthetic acaricides with new, safer agents, due to the risk of developing tolerance, toxicity and harmfulness to the natural environment associated with their overuse. The pure sugar yield is a final product in sugar beet production. The largest increases in pure sugar yield were obtained in 2021. In this year plants were exposed to drought stress in May. Smaller increases were observed in 2019, when the value of the soil moisture was high and there was no drought stress. This confirms the results of previous studies, which prove the effect of field experiments of other authors [44]. Pure sugar yield is determined by the biological yield of sugar, which depends on the yield of roots, sugar content and the content of molasses-forming components. Root yield has the greatest influence on pure sugar yield [44,45]. The control of _T. urticae_ relies mainly on the use of synthetic acaricides. This is not always effective, as this species has a high ability to develop resistant populations [46, 47, 48]. According to regulations on integrated pest management, plants should be sprayed when threshold values of economic injury are exceeded and when the pest population cannot be reduced by growing arachmid-tolerant plants or using biological methods. If several treatments are necessary, they should be performed with products from different chemical groups, representing different modes of action. Currently, selected products for the control of spider mites with different crops can be chosen from among 14 chemical groups (15 active substances) available on the world market of plant protection chemicals. There are insecticides, insecto-acaricides and acaricides. The presented pesticides are diverse in their mechanism of action. They affect the nervous system--neurootoxins (5)--inhibit the growth of mites or disturb their development (8) and inhibit lipid metabolism (2) [46,49]. In Poland, only one pesticide, Ortus 05 SC, is registered in sugar beet for the control of spider mites. Fenpyroximate (a compound from the phenoxy-pyrazole group) fightsonly mobile forms of mites, not eggs. Most populations of spider mites developed resistance to chemical groups within insecticides after a few years of use. Resistance to the ovicide clofentezine developed quite rapidly and cross-resistance to hexythiazox also occurred [50]. [PERSON] et al. [51] reported that a bromo-propylate-resistant strain (R) of _T. urticae_ showed strong positive cross-resistance towards insecticide, insecto-acaricide and acaricide, moderate positive cross-resistance towards amitraz and low negative cross-resistance towards chlorpyrifos. Resistance was detected in a relatively short period of time, leading to decreased susceptibility to all the compounds in this group [52]. In our research, we used chemical preparations and acaricide that are often used for treatments in orchards, as well as in vegetables and strawberries. The efficacy of abametcin and paraffin oil was observed. In experiments, products based on these active substances showed greater efficiency on the biological and technological yield of sugar beets. Environmental condition effects on biological and commercial traits of sugar beet is very significant. The field trials demonstrated the impact of weather conditions, especially the influence of temperature and precipitation on development of plants also development stadium of mites on the sugar beet yield.