In the period 2019-2022, at A.R.D.S. Secuieni through the implementation of the ADER 2.2.1. project, the series of observations and determinations on appearance and evolution of harmful entomofauna in rapeseed, sunflower and corn crops continued. The pests monitoring was carried out by ground surveys with a metric frame (25/25 cm), yellow bowl traps, Barber and yellow glue traps from crop emergence until plants mature. The collected material was subjected to a mathematical analysis to calculate the ecological parameters: abundance (A), dominance (D), constancy (C) and the index of ecological significance (W) which highlight the characteristics of the analyzed biocenosis. Recorded data showed that in rapeseed, the harmful entomofauna included 20 pest species that totalled on average 1207 specimens per year, whose abundance had maximum values of 523 specimens/year at the species Ceuthorynchus pallidactylus. The rapeseed species were classified into four classes of dominance, four classes of constancy and five classes of the ecological significance index. In sunflower, the harmful entomofauna consisted of 16 species, which totalled an average of 504 specimens annually, with abundance values between 1 and 182 specimens. Of the 16 species, three were classified in the D5 dominance class, two in the D4 class, five in the D3 class, and six in the D1 class as well as in classes C1 and C2. In terms of the index of ecological significance, Harpalus sp. fell into the W3 class, the rest of species being into the W1 and W2 classes. In corn, the entomofauna was also composed of 16 species totalling an average of 3720 specimens/year. The species Diabrotica virgifera virgifera had the highest abundance (2388 specimens) classified in the class of D5 dominance, C3 constancy and W5 index of ecological significance. The entomofauna harmful to rapeseed, sunflower and corn crops is quite numerous in terms of species and specimens number, which requires permanent monitoring and the application of appropriate measures to prevent attacks and control.
This paper presents studies performed for the monitoring of imidacloprid, clothianidin and thiamethoxam residues applied as seed treatment in rapeseed (Brassica napus ssp. oleifera), maize (Zea mays) and sunflower crops (Helianthus annuus). The experiments were located in representative areas of the mentioned crops. Residue levels were determined in plant samples at different phenological development stages, including flowers, as well as in bees and hive products (pollen, honeycomb, honey) by liquid chromatography/tandem mass spectroscopy (LC-MS/MS). The analyses were performed in ISO 17025-accredited laboratories, referring to the limit of quantification (LOQ), characteristic of the method used to determine the residues. In 2019, the percentage of samples that contained residues of the three substances, applied to the seed, was 16.39%, representing 20 samples out of the total of 122 analyzed samples. In 2020, 10 samples contained neonicotinoid residues above the LOQ, including 5 soil samples and 5 plant samples, representing 6.17% of the total samples. In 2021, from 149 samples with neonicotinoid applied as seed treatment, residues were identified in 12 soil samples and 11 plant samples, representing 15.43% of the total number of samples. In 2022, only 12 soil samples and 1 pasture sample contained residues above the LOQ. The results show that the highest percentage of samples with residues above the LOQ was recorded by the soil samples, while the flower and bee samples had the lowest percentages of samples with residues above the LOQ; no residues of the three neonicotinoid substances were identified in the honey samples.
"Rapeseed, the first crop established in autumn, is a species that attracts a large number of pests, from emergence to the siliquae formation and seed. Decreased production due to the attack of harmful insects can vary between 30-50%, in certain years, they can completely compromise crops. This paper presents data on the entomofauna harmful to rapeseed crops and the influence of measures to prevent and combat attacks, under specific conditions in the Central area of Moldova. The results obtained between 2017 and 2020 showed that the harmful entomofauna of rapeseed was composed of 23 species of insects, classified in five systematic orders: Coleoptera, Lepidoptera, Heteroptera, Hymenoptera and Homoptera. According to the number of species and the number of specimens collected, the order Coleoptera had the maximum share of 73.9% and respectively 88.9%. Within the order Coleoptera, the most abundant species were Phyllotreta atra (41.4%), Meligethes aeneus (27.8%), Ceuthorynchus assimilis (9.6%) and Phyllotreta nemorum (7.3%). Out of the total pest entomofauna, it was found that 30% affect rapeseed crops in the period between seed germination-plant emergence-leaf rosette formation, 9.1% in budding phase, 38% in flowering and 1.8% up to 2.8% in the phenophases of siliquae formation and seed. To prevent the attacks of soil pests (P. atra, P. nemorum, Psylliodes sp., Athalia rosae) was achieved by chemical treatment of the seed with Imidacloprid, Clothianidin and Thiamethoxam. The product Lumiposa 625FS-11.4 l/t seed was experimented with good results in seed treatment. To reduce the attacks of the pests during the flowering period (M. aeneus, A. rosae, Epicometis hirta, Ceuthorynchus assimilis) three treatments were applied on vegetation as follows: Decis Mega-0.075l/ha; Biscaya-0.3 l/ha; Mavrik-0.2 l/ha. This work was carried out within ADER 4.1.5 and 2.2.1 projects."
" Romania registered in the last years record productions for maize, being in 2019, on the first place in Europe and also, according to Eurostat data, the eighth agricultural power in Europe. The European Commission closely monitors the possible relations between bee health and pesticides and is determined to take the most cautious approach possible to protect bees. In 2013, the European Commission severely restricted the use of plant protection products for seed treatment and treated seeds containing three neonicotinoids (clothianidin, imidacloprid and thiamethoxam) in order to protect honeybees (Regulation (EU) No 485/2013). Due to the restrictions imposed on Romanian farmers, they are facing an alarming increase in the population density of some soil pests, the most dangerous being Tanymecus dilaticollis and Agriotes spp., no other insecticides being available for maize seed treatment against T. dilaticollis in Romania. In this context, since 2018, the Ministry of Agriculture and Rural Development together with the Academy of Agricultural and Forestry Sciences funded researches to monitor populations of T. dilaticollis and Agriotes spp., but also the residues level of neonicotinoid insecticides from soil, plants in various development stages (leaves and inflorescences), as well as in bees and hive products (pollen, honey). Studies were performed in three areas of Romania, respectively, Moldova (Neamt County) and south of country (Calarasi County) where T. dilaticollis exceed the economic damage threshold (4-5 adults/sqm) and Subcarpathian hills (Arges county), where Agriotes spp. populations exceed the economic damage threshold (2-4 larvae/sqm), areas where maize is the main crop. Regarding the evolution of maize leaf weevil an wireworms population in the period 2018-2020, from the data obtained it can be observed that the number of adults/sqm has remained above the economic damage threshold. Regarding neonicotinoids residues monitoring, the samples were taken from maize crops at various growth stages, including inflorescences, from bees, pollen and honey samples, too. Residues levels were determined in accredited laboratories from Germany, France and Bulgaria using certificated methods. Of the total samples, most with residues content above LOQ (limits of quantification), are soil samples, an absolutely normal situation, as the neonicotinoids were applied as seed treatment. It is also very important to mention that the lowest percentage of samples with residues above the limit of quantification, was recorded in inflorescences, honey and bees samples, the annual deviations being insignificant. It has to be highlighted that the environmental factors, especially the humidity, influenced the repeatability of the results (for example: the rainfalls during the sowing period favored the toxic substances levigation in soil)."
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