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Sugar beet production remains unprotected after the ban on neonicotinoids, while pest pressure is increasing. Although the organic approach to agriculture is highly welcomed, the question remains whether it will be possible to grow sugar beet without pesticides. The aim of this study is to determine the efficacy of seed treatments with neonicotinoids on the main sugar beet pests, to determine the susceptibility of the pests under the specific climatic conditions and to discuss possible consequences of the ban of neonicotinoids on the future of sugar beet production in southeast Europe. The study was conducted in two different climatic regions in Croatia in two consecutive years. The tested variants were: seed coated with imidacloprid, seed coated with a combination of thiamethoxam and teflutrin and untreated control. Our results showed that seed coatings with imidacloprid and thiamethoxam provided satisfactory protection against wireworms, flea beetles and sugar beet weevils at low population pressure. These pests are regular pests of sugar beet in southern and eastern Europe and therefore need to be controlled. Caterpillars and aphids were present in low populations, so the efficacy of the insecticides tested cannot be determined with certainty. A further research program is needed to find alternative solutions and develop easily implementable strategies for all sugar beet pests. We would propose an authorization of neonicotinoids for seed treatment of sugar beet in the regions with high infestation pressure of the main sugar beet pests.

Vegetable seeds have high commercial value, in the field after sowed seeds were exposed to unfavorable environmental conditions capable of causing reductions in the yield. Thiamethoxam is a bio-activator that may confer tolerance to stresses. In this regard, we aimed to evaluate the influence of thiamethoxam in the physiological performance of four lots of tomato and onion seeds. Seeds were treated with five doses of thiamethoxam, 0.0; 0.2; 0.4; 0.6 and 0.8 ml of product per 1000 seeds. The effects of the seed treatments were evaluated by the assessments of the first count of germination, sprouting test, cold test, accelerated aging and seedling`s emergence in the greenhouse. The experimental design was completely randomized, with four replicates per lot and by species. Data were submitted to analysis of variance and adjusted by orthogonal polynomials, using the adjusting equation based on the significance of F test at 5% probability. The bioactivator provided an increase in germination percentage, the first count of ermination, germination after accelerated aging, cold test and seedling’s emergence for low vigor seed lots. The bioactivator thiamethoxam stimulates the physiological performance of tomato and onion seeds. Doses of 0.5 to 0.6 mL of thiamethoxam per 1000 seeds of tomato and onion correspond to technical maximum efficiency.

International audience; AbstractPesticides are a possible cause of pollinator decline and honey bee colony losses experienced in several countries in recent years. In the past years, many north-west Italian beekeepers reported the presence of dead brood in field apiaries during neonicotinoid-coated maize sowing; therefore, a possible role of these insecticides was suspected. The objective of this study was to test this hypothesis. Laboratory repeated dose toxicity tests on in vitro reared larvae were carried out using thiamethoxam. The repeated treatment median lethal concentration (LC50) and the median lethal dose (LD50) 14 and 19 days after grafting were calculated and resulted of the same order of magnitude of realistic brood exposure under a worst-case scenario. Various sublethal effects, like brownish larvae, duplication of the pupal integument, delay in development, and deformed adults were also observed.

Simultaneous occurrence of different harmful species in agricultural practice necessitates that different plant protection chemicals be applied at the same time (tank mix). Mix components differ in purpose, mode of action and/or formulation, while addition of no pesticide components (complex fertilizers, adjuvant and wetting agents) is widely practiced today. However, data concerning the effects of water quality used for preparation of working liquids on the biological effects of pesticides is still scarce. Therefore, the objective of this study was to determine insecticidal effects as depending on components used in mixes and water hardness. The effects of mixtures of thiametoxam (Actara 25-WG 0,07kg/ha) with azoxystrobin (Quadris 0.75 l/ha), mancozeb (Dithane M-70 2.5 kg/ha), a complex fertilizer (Mortonijc plus 3 kg/ha) and a wetting agent (Silwet L-77), depending on the components and water hardness (slightly hard (15.4 d?) - tap water from Novi Sad, and very hard (34.7 d?) - well water from Adica, a Novi Sad suburb), were determined in a bioassay based on adult mortality rate of the first generation of Colorado potato beetle (Leptinotarsa decemlineata Say). The mixtures were applied by a flooding method. The trial was set up to include four replications. Insecticidal effects were determined 24 h and 48 h after exposure. Thiametoxam effectiveness 24 h and 48 h after application in slightly hard water was 100% when the insecticide was applied alone and in double and triple mixes with the fungicides, complex fertilizer and wetting agent, showing no dependency on mix components. The tested adult population of Colorado potato beetle demonstrated high susceptibility to thiametoxam, while the other components had no impact in slightly hard water. In very hard water, 24 h after application, the insecticidal effect had the same level of significance to thiametoxam in double and triple mixes, with an exception of thiametoxam+mancozeb+Mortonijc plus and thiametoxam+mancozeb+wetting agent combinations, which showed significantly lower efficacy. After 48 h, substantially lower effectiveness, in comparison with the sole insecticide and other combinations, was only observed in thiametoksam+mancozeb+Mortonjic plus combination. Significantly lower efficacy of that combination is probably due to an incompatibility of the macozeb preparation and the complex fertilizer containing boron (B), which was evidenced only in very hard water.

International audience; Here, we describe the synthesis of two new fluorescent derivatives of thiamethoxam and compared their toxicity on aphid Acyrthosiphon pisum and their mode of action on insect nicotinic acetylcholine receptors expressed on the sixth abdominal ganglion. The compound 3 with two 2-chlorothiazole moieties was found to be more toxic using toxicological bioassays 24 h and 48 h after exposure while compound 4 appeared more active using cockroach ganglionic depolarization. Interestingly, thiamethoxam appeared more effective than component 3 and 4, respectively. Our results demonstrated that component 3 and 4 act as agonists of insect nicotinic acetylcholine receptors