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The experiments were carried out on 5 different bioproducts for control of Verticillium longisporum in oilseed rape. For in vitro trials, greenhouse trials and field trials, the bioproducts used were based on bacteria (Bacillus amyloliquefaciens, Pseudomonas veronii) and fungi (Pythium oligandrum, Trichoderma asperellum, Coniothyrium minitans). In in vitro trials, some products (based on Trichoderma asperellum) showed a 100% inhibition effect on the pathogen for a whole trial period of 45 days. The greenhouse trial showed significant differences in bioproducts effectiveness (P < 0.00723) compared to control. Three bioproducts (based on Coniothyrium minitans, Trichoderma asperellum and Pseudomonas veronii) showed a 100% inhibition effect against the pathogen. In field trials conducted in 3 locations, there were some differences in yield, which can be important for growers and practice use. The highest yield (19.1% higher than the control) was achieved with a bioproduct based on Trichoderma asperellum. In trials, it is possible to see that there are promising results that can be used for further testing.

Glyphosate is a widely used agrochemical. Nevertheless, only a few studies have investigated its effect on bees, specifically its influence on their foraging activity. This article provides a summary of the prominent research results on this issue, published in journals in the field of experimental biology. The effect of commonly used concentrations of glyphosate on honey bee navigation has been evaluated in several studies, as well as concentrations that are reportedly sublethal. Exposure to this herbicide increases the flight time back to the hive and affects the flight trajectories of these bees. These results imply that glyphosate at certain concentrations reduces their sensitivity to nectar rewards in associative memories. The contact of bees with non-lethal concentrations of glyphosate results in sublethal effects that affect foraging. In the future, the behaviour of glyphosate and its effect on bees in their natural environment need to be explored.

The honey bee is one of the insects that is significantly endangered by the application of pesticides in the cultivation of crops. Not only is acute toxicity dangerous, but the importance of chronic poisoning by low doses of pesticides in hives is growing. The behavior of bees can be affected not only by insecticide residues but also by herbicide and fungicide residues. In 2016-2018, samples of bee bread were analysed for pesticide content at 25 different localities from intensive agricultural production areas of the Czech Republic. Substances were extracted by QuEChERS and determined by liquid chromatography, together with mass spectrometric detection. We detected up to 18 pesticides in one sample. In total, during 2016-2018, we identified 53 active substances. Fifteen substances (31%) were herbicidal, 23 substances (47%) of fungicidal nature and 6 substances (12%) of insecticidal nature. The coefficient of variation showed large differences in the frequency of revealed pesticides between years. For substances sprayed outside period attractive for pollinators (mainly herbicides and some fungicides), the usual methodology cannot reliably determine the degree of contamination, and thus the actual contamination with these substances may be even higher than demonstrated in this study.

Currently, the hybrid cultivars are predominant in the cultivation of winter oilseed rape in Europe. Cultivation of hybrid cultivars instead of the traditional line can affect the visitation of pollinators. Beekeepers and farmers claim that hybrid cultivars are not visited by pollinators as much as the line. Ten yellow and one white flowering oilseed rape cultivars were used to compare the visitation rates of pollinators (Apis mellifera L. and Bombus sp.) during flowering in the years 2015-2017. At the same time, the visitation of hybrid and line cultivars by pollinators was evaluated. Visitation of pollinators on each cultivar was calculated from observed visitations to flowering oilseed rape plants in an area 2.1 m2 from the edge of single plots for 20 s. The results from this study clearly show that the individual cultivars, whether hybrids or lines, did not have a major influence on the pollinators' visitation, either by honey bees or bumble bees. It is thus proved that hybrid cultivars do not affect the pollinator visitation and there is no need to worry about the prevalence of these cultivars in the Czech fields. However, a more significant effect for both pollinator groups appears to have been the color of the flower.

Influence of plant growth regulators chlormequat chloride, chlormequat chloride + ethephon, ethephon, and mepiquat chloride + prohexadione-Ca + pyraclostrobin + ammonium sulphate (BAS67800F + BAS00800D) on decreasing sunflower height was evaluated. It was determined that sunflower height can be reduced by as much as 30 cm. In the case of BAS67800F + ammonium sulphate, there was a slight difference between application at BBCH 31-33 and BBCH 50-51, whereas for ethephon better application time was at BBCH 50-51. For chlormequat chloride, application at BBCH 31-33 was better, but height reduction did not endure until harvest. Flower head diameter shortly before harvest was not affected at any tested regulator. Flowering was delayed primarily at applications at BBCH 50-51.

Winter oilseed rape is the second most frequently grown crop in the Czech Republic. Clubroot, caused by Plasmodiophora brassicae (Wor.), was previously a problem in production of vegetable. The disease has been spreading on winter rape (Brassica napus L.) over the past four years. Infected stands were reported throughout the country in autumn 2011. The pathogen is probably widely spread in the whole country, its incidence depends on suitable weather conditions. Every field with clubroot is considered as contaminated for many years. The amounts of inoculum and its distribution are not sufficient yet, but this is just the initial stage of colonisation. There is a similar situation resembling experiences from other countries (Canada, Germany) where clubroot has gradually expanded in the last 15 years.

Effect in reducing maize plant height using growth regulators ethephon, chlormequat chloride (CCC), CCC + ethephon, and mepiquat chloride + prohexadione-Ca was studied in field experiments during 2010 and 2011. It was found that maize plant height could be reduced by as much as 125 cm (49% of control) using a double application of ethephon (576 g a.i./ha) at growth stages BBCH 18-19 and BBCH 34-36. The other growth regulators displayed weak or no influence. An optimum level of shortening was achieved using ethephon (576 g a.i./ha) at BBCH 34-36 (reducing plant height by 40-90 cm), but it is necessary to count upon yield loss of 0.5-0.6 t/ha.

During 2010-2012, we monitored flight activity of male and female stem weevils (Ceutorhynchus napi, C. pallidactylus) using yellow water traps, the effectiveness of various application dates for the insecticide thiacloprid (72 g active ingredient/ha), and the influence on yield. The first occurrence of beetles in traps was recorded after soil temperature at 5 cm reached 8°C in all experimental years. In all years, males of C. pallidactylus dominated in the traps and the times of beetles' first occurrence. The most effective applications of thiacloprid at the stated rate were 14 days (2010), 6 days (2011), and 1 day (2012) after peak flight. Females with eggs appeared in bowls in 2010 and 2012 at first flight, while in 2011 no females were recorded. After the most effective applications, yields increased significantly in 2010 (+5% vs. the control) and in 2011 (+4%), and insignificantly in 2012 (+2%).

In experiments using Petri dishes in the laboratory and pots in a greenhouse and climate chamber, we examined the influence of seed treatment on emergence of poppy. Four types of fungi (Alternaria spp., Dendryphion penicillatum, Fusarium spp., and Penicillium spp.) were detected on poppy seeds, with the highest infection rate being 72% for D. penicillatum. Surface disinfection decreased infection rate chiefly in D. penicillatum (by 32%) and in Alternaria spp. (by 16%). Seed treatment increased emergence by 9-10% in laboratory experiments but by only 0-6% in greenhouse experiments. Temperature plays an important role in emergence. In climate chamber experiments at a stable temperature of 12°C, the seed treatments increased emergence by 8-16%.

In experiments with winter rape during 2004-2008, we examined the effectiveness of fungicides containing active ingredients based upon triazoles and SBI inhibitors (group A): flusilazole 250 g/l a.i., flusilazole 125 g/l a.i. + carbendazim 250 g/l a.i., and cyproconazole 120 g/l a.i. + carbendazim 300 g/l a.i. Fungicides based upon older and newer triazoles, strobilurins, and SDH inhibitors (group B) were also used: cyproconazole 80g/l a.i. + azoxystrobin 200 g/l a.i., prothioconazole 250 g/l a.i., prothioconazole 125 g/l a.i. + tebuconazole 125 g/l a.i., and boscalid 200 g/l a.i. + dimoxystrobin 200 g/l a.i. The application of group A fungicides against S. sclerotiorum during BBCH 65-69 growth stage had demonstratively higher effectiveness, while for group B the application date had no effect. The greening (or "stay-green") effect only occurred with group B. The correlation coefficient for greening effect and yield was R = -0.3033 for applications during BBCH 61-65 while it was R= -0.3542 for BBCH 65-69 stage, thus indicating a relatively weak relationship.

In 2005 we determined the effectiveness of two preparations against gall pod midge in dependence on different terms of application, i.e. at full flowering (BBCH 65) and after flowering (BBCH 67) of winter oilseed rape. The tests were carried out at three localities in the Czech Republic, and the two preparations used were Calypso 480 SC (a.i. thiacloprid) and Karate Zeon 5CS (a.i. lambda-cyhalothrin). It was found that applying the preparations at BBCH 67 was significantly more effective than treatment at BBCH 65.

The acute and chronic toxicity to honeybees, Apis mellifera of water guttation and dew collected from winter rape plants treated with the insecticide Nurelle D® (a.i. chlorpyriphos + cypermethrin) was investigated. Caged bees were fed on sugar syrup containing water guttation and dew for 24 h (acute toxicity test) and for 10 days (chronic toxicity test). Bee mortality and food consumption were determined daily. A contact toxicity test was performed within 24 h on bees kept in Petri dishes (10 bees per dish) lined with filter paper saturated with the test solution. The acute Nurelle D® contact and oral toxicity tests showed that the mortality of bees treated with water guttation and dew collected from the treated plants did not exceed 10%. A chronic toxicity test showed that adding contaminated water guttation and dew to the syrup caused an insignificant increase in bee mortality and reduced the syrup consumption significantly. The chlorpyriphos residue found in contaminated water guttation and dew were below the limit of detection (0.8 µg/kg) and the cypermethrin residue was below the detection levels.

The effects of NeemAzalTM formulations: NeemAzalTM T/S (1% azadirachtin) and NeemAzalTM granules (1% azadirachtin) on honeybees, Apis mellifera L., were studied under semi-field conditions. Three plots at 15 m2 each were sown with spring rape seeds Brassica napus cultivar Likolly (Brassicaceae/Cruciferae). In the first plot NeemAzal granules were added with the seeds during sowing. The second plot was sprayed with NeemAzal T/S during full flowering; GreemaxTM was used as a wetting agent. The third one was sprayed with water only during full flowering as a control. For each treatment one tunnel tent (3 × 5 × 2 m) was used during the flowering period. Small bee colonies were exposed to the treated plants for 7 days. Evaluation was carried out by comparing the results in the treatments to the control and, furthermore, by comparing the pre- and post-application. The mortality in the tunnels and the flight activity were checked before, as well as after the treatment. The development of the bee brood was evaluated by using transparent acetate sheets to mark single cells in brood combs with their contents on different assessment dates. The time schedule of the assessment dates was chosen in order to check the bee brood at different expected stages during the development. The development of the bee brood was evaluated by calculation of brood termination rates in percentage and brood indices. The results show that residues of NeemAzal granules did not adversely affect bee mortality, foraging activity or brood development. By contrast, it was noticed that NeemAzal T/S caused some reduction in foraging activity and brood development.