Vaneva-Gancheva T.,Institute of Tobacco and Tobacco Products |
Dimitrov Y.,Agricultural University of Plovdiv
Bulgarian Journal of Agricultural Science | Year: 2013
For the purpose of assessing the potential of chemical compounds belonging to different groups (acetamiprid, deltamethrin, imidacloprid and chlorpyrifosethyl + cypermethrin - registered to be used on tobacco in Bulgaria and also indoxacarb and chlorantraniliprole - not registered) to control the attacks of the potato tuber moth Phthorimaea operculella (Zeller) on tobacco, their ovicidal and larvicidal effects have been established under laboratory conditions. Their biological efficiency has also been assessed under field conditions by controlling the extent of the damages caused to the tobacco. Depending on the degree of influence on the eggs, the analyzed substances rank as follows: chlorpyrifosethyl+cypermethrin > deltamethrin > acetamiprid > indoxacarb > imidacloprid > chloranrhaniliprole. Chloranrhaniliprole, chlorpyrifosethyl+cypermethrin and deltamethrin demonstrate the fastest and the strongest effect on the young larvae of the potato tuber moth > 90% mortality. Indoxacarb and acetamiprid also achieve a high mortality rate of > 90% but the effect is slower. Imidacloprid demonstrates the weakest larvicidal effect during the laboratory testing. In accordance with the effectiveness, which is based on the control over the extent of damages under field conditions, the active substances rank as follows: chlorantraniliprole > indoxacarb > deltamethrin > chlorpyrifosethyl+cypermethrin > acetamiprid > imidacloprid. Chlorantraniliprole and indoxacarb provide the most effective and the longest control on the potato tuber moth but, unfortunately, they have not been registered on tobacco. Of all the active compounds registered to be used on tobacco, deltamethrin and chlorpyrifosethyl+cypermethrin can be successfully applied during the attacks of the potato tuber moth and to exercise mutual control over tobacco pests. Acetamiprid and imidacloprid can be applied together to control tobacco pests and also during the attacks of the potato tuber moth in the initial stages after planting, i.e. as the period of protection of the tobacco plants is extended, the extent of damages increases.
Dospatliev L.,Trakia University |
Zaprjanova P.,Institute of Tobacco and Tobacco Products |
Ivanov K.,Agricultural University of Plovdiv |
Angelova V.,Agricultural University of Plovdiv
Bulgarian Journal of Agricultural Science | Year: 2014
The study was conducted on alluvial-meadow, maroon-forest soils and vertisols with Virginia tobacco. The total content of iron was measured through decomposition by HF, HClO and HNO acids. A solution of 0.005 M diethylentriaminepentaacetic acid + 0.1 M triethanolamine, pH 7.3 was used for extraction of the elements’ mobile forms from soils. The plant sample preparation was made by means of dry ashing and dissolution in 3 M HCl. A Varian Spectra AA 220 Atomic Absorption Spectrophotometer was used for Fe content determination in soil and plant samples. Certified reference materials (three types of soils and tobacco leaves) were also analyzed for accurate determination of Fe concentrations. A correlation and regression analysis was conducted between pH, humus content, total and mobile iron forms in the soil, and the concentration of these elements in aboveground biomass of Virginia tobacco. It was estimated that there were statistically significant relationships between soil pH and iron concentration in Virginia tobacco plant organs. The correlation - regression analysis results showed that there were no statistically significant relationships between humus and iron concentration in aboveground tobacco biomass of Virginia tobacco. Also, the results of the correlation - regression analysis showed that there were no statistically significant relationships between the total element content in soils and iron content in aboveground tobacco biomass of Virginia type. Regression relationships were established between movable iron in the soil and element content in leaves from the lower, middle and upper harvesting zones. © 2014, National Centre for Agrarian Sciences. All rights reserved.
Bozhinova R.,Institute of Tobacco and Tobacco Products
Journal of Central European Agriculture | Year: 2012
The effects of the different potassium rates (0, 75 and 450 kg K2O ha-1) on nutrient concentrations in the above-ground biomass and chemical characteristics of sun-cured tobacco have been studied in a stationary field trial. Annual fertilization with 75 kg K2O ha-1 was adequate to maintain soil K concentration near the initial value. It was found that yield of cured leaves was not significantly affected by rate of K application when oriental tobacco was grown on soils with high available soil K. With the increase of K fertilization rate the content of the potassium in leaves increased from 0.65 to 4.49%. The concentration of Ca and Mg in the leaves ranged from 2.03 to 5.23% and from 0.52 to 0.71%, respectively and decreased with increases in added potassium. No effect of K rates on nicotine and protein content was noted. Only the reducing sugars' content tended to increase to 11.42% at the highest K rate. Fertilization with moderate potassium rates (75 kg K2O ha-1) on soils high in available K is necessary to maintain the good potassium reserves. When oriental tobacco was grown on alkaline soils with high available K and Ca, potassium fertilization improves K nutrition and therefore may favorably affect burning properties of tobacco.
Zaprjanova P.,Institute of Tobacco and Tobacco Products |
Dospatliev L.,Plovdiv University |
Angelova V.,Plovdiv University |
Ivanov K.,Plovdiv University
Environmental Monitoring and Assessment | Year: 2010
The study was conducted on alluvial-meadow, maroon-forest soils and vertisols with Virginia tobacco. The total content of lead and cadmium is measured through decomposition by HF, HClO4, and HNO3 acids. A solution of 0.005 M diethylentriaminepentaacetic acid + 0.1 M triethanolamine, pH 7.3 was used for extraction of the elements' mobile forms from soils. The preparation of plant samples was made by means of dry ashing and dissolution in 3 M HCl. An atomic absorption spectrometer "Spektra AA 220" of the Australian company Varian was used for determination of Pb and Cd content in the soil and plant samples. Certified reference materials (three soils and tobacco leaves) were also analyzed for the verification of the accuracy of Pb and Cd determination. A correlation/regression analysis was conducted between pH, humus content, total and mobile forms of lead and cadmium in the soil, and the concentration of these elements in the aboveground biomass of Virginia tobacco. It was established that there are no statistically significant dependencies determined between soil pH and lead concentration in the plant organs of Virginia tobacco. Regressional dependencies of great significance were determined between the humus content, total and mobile lead and cadmium in the soil, and the element concentration in the leaves of the three harvesting zones. © 2009 Springer Science+Business Media B.V.