Allelopathic potential of sunflower (Helianthus annus) water extracts to reduce the pendimethalin herbicide dose to control Chenopodium album in corn (Zea mays)

摘要

In field studies, we evaluated the combinations of sunflower (Helianthus annus) extract and reduced doses of herbicide pendimethalin to control Chenopodium album in corn field. The experimental treatments were: control, pendimethalin full dose (600 mL ha(-1)), pendimethalin half dose (300 mL ha(-1)), sunflower extracts (10 and 20%), pendimethalin half dose + 10% sunflower extract and pendimethalin half dose + 20% sunflower extract. Combinations of sunflower extract (20%) with pendimethalin half dose, drastically decreased the C. album density and seedling weight (81.3% and 82.8% inhibition over control) than other treatments except pendimethalin full dose. The minimum LAI of C. album was with pendimethalin full dose (75.5 %) and pendimethalin half dose + 20% sunflower extract (71 %). Pendimetalin full dose and pendimethalin half dose + 20% sunflower extract decreased the photosynthesis to 59% and 55% of control, respectively. All treatments increased the ABA contents in C. album seedling, but the highest ABA content was with pendimethalin full dose (74.7%) and pendimethalin half dose + 20% sunflower extract treatments (75.4 % over the control). We concluded that the phytotoxic effects of sunflower extract tank mix with pendimethalin could reduce the herbicide doses for C. album control.