تاثیر حشره‌کش‌های گیاهی و میکروبی برروی سرخرطومی برگ یونجه (Hypera postica Gyllenhal.)

The importance of alfalfa lies in its abundant biomass production, adaptability to most climates, efficient energy content, and its role as a significant source of biological nitrogen fixation. The alfalfa weevil (Hypera postica Gyllenhal.) is one of the most dangerous pests of alfalfa worldwide. Both larvae and adult weevils damage the central buds and leaves of the plant. Currently, chemical control is the primary method used to prevent damage from this pest in alfalfa fields, leading to ongoing environmental pollution. However, pesticide usage can be reduced within integrated pest management (IPM) programs. This study was conducted in an alfalfa field infested with alfalfa weevils, using the Hamadani cultivar, three years old, located in the village of Qurt Tappeh, northeast of Urmia. The experiment was designed as a randomized complete block design with ten treatments and four replications. The treatments included: Palizin at 2.5 ml/L, Azadiraktin at 2 ml/L, Tondaksir at 2.5 ml/L, Naturalis at 3 ml/L, Biobit at 2.5 ml/L, Basiokara at 3 ml/L, and two combination treatments of Azadiraktin at 1 ml/L + Basiokara at 1.5 ml/L, Tondaksir at 1.25 ml/L + Biobit at 1.25 ml/L, along with Cypermethrin at 2 ml/L, and water as the control. Spraying was carried out concurrently with the activity of larvae at various stages, and samples were taken of live larvae before and after spraying at intervals of three, seven, and fourteen days post-treatment. The results of the analysis of variance showed that the treatment effect on larval mortality percentages at three, seven, and fourteen-day intervals in the first year was significant at the 1% probability level. In the second year, the treatment effect, except for the seven-day interval, was significant for the three and fourteen-day intervals. Mean comparisons indicated that the biological insecticide Azadiraktin had a favorable lethal effect on this pest. The combined analysis over two years revealed that the treatment effect and the interaction effect of year and treatment for the third, seventh, and fourteenth days were significant at the 1% probability level. Additionally, the results indicated that botanical insecticides had the highest percentage of alfalfa weevil mortality on the third day, and microbial formulations showed the highest mortality on the fourteenth day post-spraying.