U. Menkissoglu - Academia.edu (original) (raw)

Papers by U. Menkissoglu

Pest Management Science, 2008

Acaricide used in beehives for the control of varroa often leaves residues in bee products. The b... more Acaricide used in beehives for the control of varroa often leaves residues in bee products. The behaviour and distribution of the acaricide coumaphos in honey following the application of a new slow-release strip formulation (CheckMite+) was assessed. The bee colonies were allowed to build new combs without foundation, and two strips were hung in the brood chamber of each colony for a period of 42 days. The distribution of coumaphos residues in honey in relation to the position of the frame and the duration of treatment was examined by collecting samples from each comb at various time intervals up to 145 days after treatment. In the brood chamber, coumaphos was incorporated into honey from the first day of application, and residues accumulated mainly in combs placed next to strips. In the adjacent combs, residues remained at low concentrations with slight variations. In the honey chamber, residue concentrations on the day of strip removal ranged between 0.006 and 0.020 mg kg(-1), while 79 days after application the concentration of coumaphos residues was below 0.020 mg kg(-1). Residues above the EC fixed maximum residue limit (MRL) of 0.1 mg kg(-1) were measured only in brood chamber honey obtained from those combs placed next to strips. In these samples, 0.060-0.111 mg kg(-1) of coumaphos was detected up to 103 days after strip removal. Coumaphos residues in honey extracted from combs that were placed at the edge of the brood chamber were found below the MRL value, even during the 42 day period of CheckMite+ strip treatment.

Pest management …, 2008

Pest Management Science, 2014

Chemosphere, 2004

Rapid degradation of cadusafos was evident in soils collected from previously-treated field sites... more Rapid degradation of cadusafos was evident in soils collected from previously-treated field sites from a potato monoculture area in northern Greece. The slower degradation of cadusafos observed in corresponding antibiotictreated soils as well as in soils from an adjacent previously-untreated field demonstrated the microbial involvement in the rapid degradation of cadusafos in the soils from the previously-treated sites. Application of the non-specific antibacterial antibiotic chloramphenicol or of the Gram+ bacteria-inhibiting antibiotics penicillin + lyncomycin + vancomycin significantly inhibited the rapid biodegradation of cadusafos suggesting that soil bacteria and probably Gram+ bacteria are mainly responsible for the rapid biodegradation of cadusafos in the specific soil. Further experiments showed that the bacterial population of the cadusafos-adapted soil was also able to rapidly degrade the chemically related nematicide ethoprophos but not fenamiphos and oxamyl. This is the first report of the occurrence of enhanced biodegradation of cadusafos in potato fields. In addition, the finding of cross-enhancement between cadusafos and ethoprophos significantly reduces the number of available chemicals which could be alternated to prevent the development of enhanced biodegradation and thus intensifies the problem in potato monoculture areas like the one in northern Greece.

Chemosphere, 2010

The composition of biomixtures strongly affect the efficacy of biobeds. Typically, biomixture con... more The composition of biomixtures strongly affect the efficacy of biobeds. Typically, biomixture consists of peat (or compost), straw (STR) and topsoil (1:2:1 by volume). Straw guarantees a continuous supply of nutrients and high microbial activity. However, in south Europe other lignocellulosic materials including sunflower crop residues (SFR), olive leaves, grape stalks (GS), orange peels, corn cobs (CC) and spent mushroom substrate (SMS) are also readily available at no cost. Their potential utilization in biomixtures instead of STR was tested in pesticide degradation and adsorption studies. The microbial activity in these biomixtures was also assessed. The GS-biomixture was the most efficient in pesticide degradation, while CC-and SFR-biomixtures showed comparable degrading efficacy with the STR-biomixture. The SMS-biomixture was also highly efficient in degrading the pesticide mixture with degradation rates being correlated with the proportion of SMS in the biomixture. Microbial respiration was positively correlated with the degradation rates of metalaxyl, azoxystrobin and chlorpyrifos, compared to phenoloxidase which showed no correlation. Biomixtures containing alternative lignocellulosic materials showed a higher adsorption affinity for terbuthylazine and metribuzin compared to the STR-biomixture. We provide first evidence that STR can be substituted in biomixtures by other lignocellulosic materials which are readily available in south Europe.

The chemical composition of the essential oils isolated from various parts of three Greek aromati... more The chemical composition of the essential oils isolated from various parts of three Greek aromatic plants (Lavandula hybrida Rev, Rosmarinus officinalis L and Eucalyptus globulus Labill) collected at different seasons was determined by GC/MS analysis. The insecticidal action of these oils and of their main constituents on Acanthoscelides obtectus (Say) adults was evaluated and their LC50 values were estimated. All essential oils tested exhibited strong activity against A. obtectus adults, with varying LC50 values depending on insect sex and the composition of the essential oils. A correlation between total oxygenated monoterpenoid content and activity was observed, with oxygenated compounds exhibiting higher activity than hydrocarbons. Among the main constituents, only linalyl and terpinyl acetate were not active against A. obtectus, while all the others exhibited insecticidal activity against both male and female adults, with LC50 values ranging from 0.8 to 47.1 mg litre(-1) air. An attempt to correlate the insecticidal activity to the monoterpenoid&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s structure is presented, and the difference in sensitivity between male and female individuals is also explored.

The influence of secondary metabolites on the bacterial colonization of the phyllosphere of four ... more The influence of secondary metabolites on the bacterial colonization of the phyllosphere of four aromatic species of the Mediterranean region was studied for the determination of total bacterial populations (TBP) and populations of ice nucleation active bacteria (INA). The aromatic plants used were lavender (Lavandula angustifolia), rosemary (Rosmarinus officinalis), Greek sage (Salvia fruticosa), and Greek oregano (Origanum vulgare subsp. hirtum), all growing in neighboring sites. Lavender was heavily colonized by bacteria, whereas rosemary, sage, and oregano were poorly colonized. The differences in bacterial colonization were related to the plants' content of secondary metabolites and their antimicrobial activity, as recorded in the in vitro bioassays. Lavender had the lowest amount of surface phenolics, the lowest concentration of essential oil, and the overall weakest antibacterial activity. Among the epiphytic bacteria, ice nucleation active ones were not detected on oregano and sage leaves but were found in extremely low numbers on those of rosemary and lavender. For this reason, these aromatic plants were further studied regarding their effect against two INA bacteria, Pseudomonas syringae and Erwinia herbicola. Minimum inhibitory concentrations and minimum bactericidal concentrations were estimated for the essential oils and for their main constituents under different bacterial populations. The antibacterial effect of Labiatae aromatic plants against INA bacteria not only explains the scarce presence of the latter on their leaves but may have applications in agriculture as a frost-control method for sensitive crops.