Pulicaria salviifolia and P. gnaphalodes belong to one of the richest terpenoid plants of the genus Pulicaria (family Asteraceae). The genus includes 63 species, 16 species grow in Uzbekistan. In folk medicine, plants are actively used to treat various diseases, and have long been used as a natural remedy for mosquitoes, flies and fleas. Secondary plant metabolites are of great practical interest as a natural raw material for the creation of biopesticides. The aim of this work was to study the chemical composition of the volatile components of gasoline fractions of Pulicaria salviifolia and P. gnaphalodes plants and to study their insecticidal activity against the number of insect pests. For the first time, the composition of volatiles in the aerial parts of Pulicaria salviifolia and P. gnaphalodes was studied by GC/MS. It was revealed that the predominant components of P. salviifolia are β-terpineol (10.44%), isospatulenol (8.00%), iceol (6.79%), sabinene hydrate (5.72%), l-caryophyllene (4.24%), terpinene-4-ol (4.07%), d-cadinene (3.65%), α-amorphous (2.30%). Calaminene (12.44%), 2-phenylpyrazol-3-amine (8.61%), 1,3,5-cycloheptatriene (7.71%), 1,8-cineole (6.06%), 2-heptene dominate among the volatile substances of P. gnaphalodes-1-ol, 2-methyl-6-(4-methylphenyl)-, (E)- (6.04%), 1-bromohomoadamantane (5.73%), 7-acetyl-2-hydroxy-2-methyl-5-isopropylbicyclo[4.3.0]nonane (4.83%). Gasoline fractions of Pulicaria salviifolia and P. gnaphalodes were tested for insecticidal activity against apple aphid (Aphis pomi), peach aphid (Myzus persicae Sulzer) and cowpea weevils (Callosobruchus maculatus). An insecticidal activity was studied in laboratory conditions. A comparative study of the biological activity of the fractions showed that the biological efficiency of the P. gnaphalodes extract fraction after 24 hours at 0.5% concentration was higher: in relation to Aphis pomi 96.6%, Myzus persicae Sulzer – 76.0% and Callosobruchus maculatus – 90.0%, for the fraction of Pulicaria salviifolia extract in a 0.5% dose, these indicators were 60.2%, 72.0% and 86.6%, respectively.

Climate change and enhanced air temperatures adversely affect the wheat's (Triticum aestivum L.) morphological, physiological, biochemical, and molecular properties and grain yield. Therefore, developing high-yielding and resistant bread wheat cultivars to abiotic factors is vital, along with their primary source under varied environmental conditions. In the presented study, monitoring the influence of high temperatures (30 degrees & Scy; and above) continuously during the grain maturation period, especially in grain filling, on grain quality and productivity has undergone thorough research in the southern parts of Uzbekistan. These Southern regions mainly grow winter bread wheat cultivars. In determining the heat resistance of winter wheat cultivars typically planted in the Republic and selecting the best ones, the experiments and observations materialized with optimum and late-sowing conditions. The study determined the temperature during the growth period and daily temperatures during the grain-filling period. The research was able to evaluate the influence of air temperatures on 1000-grain weight, grain nature, and protein and gluten content and compare the results under optimum and late periods.

Insecticidal activity of the 2-Benzylthio-5-(4-Aminophenyl)-1,3,4-oxadiazole (2-BAO) against the global crop pest - Helicoverpa armigera was studied in laboratory and field, and the toxicity (LD50) of the substance was evaluated against larva H. armigera, as well as evaluate the effectiveness against H. armigera. This study aimed to determine the insecticidal activity of 2-Benzylthio-5-(4-Aminophenyl)-1,3,4-oxadiazole (2-BAO) against larvae H. armigera in vivo and in vitro. Evaluate biological effectiveness in the control of H. armigera in fields of the Tashkent region. For the first time, it was found that the derived 1,3,4-oxadiazoles at 0.1 mg/mL caused 65.5% mortality of cotton bollworm (H. armigera) after 24 h of incubation. The mortality of larvae after 48-hour incubation reached 79.9%. The toxicity of 2-BAO against larvae after 24 h was LC50 0.36 mg/mL. The insecticidal activity of the 1,3,4-oxadiazole derivative was studied for the first time in vitro against Helicopvera zea, Spodoptera frugiperda, and Trichoplusiya ni insect cells. The results obtained confirm that 2-Benzylthio-5-(4-Aminophenyl)-1,3,4-oxadiazole at a dose of 10 mu M/mL exhibits toxicity against cells of various cutworm species, which is confirmed in the experiment in vivo. The results of field trials showed that on the 7th day, the effectiveness of the substance at a rate of 0.2 kg/ha against larvae H. armigera was 56.0% compared to the control, 11.0% more compared to the insecticide BI-58 (a.i. dimethoate). The effectiveness of 2-Benzylthio-5-(4-Aminophenyl)-1,3,4-oxadiazole (2-BAO) on the 21st day reached 68.5% compared to the control. These findings suggest that it can be assumed that 2-Benzylthio-5-(4-Aminophenyl)-1,3,4-oxadiazole (2-BAO) can control the number of larvae of pests with the best control efficiency of more than 68.5% when the increasing pest population from reaching the economic injury level.

In recent years, many chemical compounds have been shown to be effective against crop insects but the practical efficacy of only a few compounds has been observed.

Mechanochemical modification of the substance of floroxan by the glycyrrhizic acid made it possible to increase the solubility of the preparation and expand the range and effectiveness of its action.

The aim of this work was that the studying the chemical composition of the n-butanol fraction of the extract of the aerial parts of Datura stramonium L. plants collected in the Fergana region of the Republic of Uzbekistan and investigation of its insecticidal activity against certain types of pests of the genus of Aphididae. It was found as a result of this study that the high efficiency of the n-butanol fraction of the extract of Datura stramonium L. against sucking pests of the genus Aphididae - Aphis pomi and Macrosiphum euphorbiae. Additionally, 10 mg/mL dose of this fraction also showed the first level activity with 98.5% against Macrosiphum euphorbiae. The level of mortality was lower at 1 mg/mL and 5 mg/mL concentration that 81.3% and 83.3%, respectively. The index was significantly low as a follows -15.1% for 1 mg/mL of the dose, 19.5% for 5 mg/mL of the dose, and 24.0% for 10 mg/mL of the dose when exposed to Schizaphis graminum. It was revealed that the n-butanol fraction of the extract of the aerial part of the Datura stramonium L. plant at a concentration of 1 mg/ml did not show phytotoxicity on the leaves of wheat, tomato, and cucumbers. The first time, it was established that 500 mu g / ml and 100 mu g/ml concentrations of the fraction showed 100% cytotoxicity against the cell line of maize deciduous scoops (Spodoptera frugiperda) under in vitro conditions and found to be non-toxic to ciliates (Paramecium caudatum) in 5 mu l of 10 mg/mL extract.

Secondary metabolites were isolated from cultures of four geographically distant isolates of the cosmopolitan fungus, Bipolaris sorokiniana for intense biological characterization. Analysis of extracts from their liquid and solid cultures with TLC and HPLC-MS showed high similarity of their composition despite on fungal origin. From the extracts of B. sorokiniana 14 metabolites (terpenes, quinones, xanthones etc.) were isolated using column chromatography and preparative HPLC; among them, 12 known substances were identified. Chloromonilinic acid B (CAB) showed the highest level phytotoxic activity on wheat leaves. The most of isolated compounds inhibited growth of Bacillus subtilis, of which methyl-8,3-hydroxy-3-methyl-4-chloroxanthon-1-carboxilate (MMC) demonstrated the strongest activity. Some metabolites of B. sorokiniana (CAB and MMC) were shown to have insecticidal activity against common cereal aphid. All the compounds were cytotoxic (especially, cochlioqionones and fusaroproliferin) when tested on Sf9 cell line. However, no one was acute toxic for infusoria. Evidently, the production of multiple bioactive compounds makes B. sorokiniana a strong competitor in different ecological niches and a dangerous contaminant of grain.