Germination and emergence of prickly lettuce (Lactuca serriola L.) and its susceptibility to selected herbicides

Three-year trials were conducted to study germination and emergence of prickly lettuce (Lactuca serriola L.) achenes, increments of shoot dry matter and susceptibility of the weed to selected herbicides. The germination rates of achenes at10°C (92%),20°C (97%) and30°C (95%) did not indicate any significant differences within 20 days from sowing. The highest percentage emergence of prickly lettuce achenes was determined after their sowing into a depth of1 mm. Differences from the variants of sowing onto the soil surface (0 mm), into a depth of 10 and20 mm were significant. There were no differences in the emergence rates from a depth of 10 and20 mm. The highest increments of shoot dry matter were observed when prickly lettuce plants were grown for 4-7 weeks after sowing at20°C. The effect of selected herbicides on prickly lettuce plants treated at the stage of 2-3 true leaves was evaluated on the basis of a change in the content of shoot dry matter. A significant decrease in dry matter against the control was recorded in all variants after herbicide application. The effect (expressed by a lower dry matter content) was significantly higher after the combination amidosulfuron + iodosulfuron-methyl + mefenpyr-diethyl (10 + 2.5 + 25 g/ha) was used than after the application of tribenuron (10.85 g/ha) and picolinafen + cyanazine (120 g + 480 h). The effect of amidosulfuron (22.5 g/ha) was significantly higher than in the variants treated with tribenuron, picloram + clopyralid (16.75 + 66.75 g/ha), clopyralid (90 g/ha) and picolinafen + cyanazine (150 + 600 g/ha). The best effects were produced by herbicides containing amidosulfuron and iodosulfuron as active ingredients.