Efficiency and cost-effectiveness of weed flaming in orchards

Abstract

The objective of this study was to determine the response and cost of weed flaming in different fruit orchards. Six different propane doses (15, 30, 45, 60, 75 and 90 kg ha-¹) were applied to determine the response of 6 dicotyledon and 3 monocotyledon weed species toflaming in apricot, walnut, and mixed fruit orchard. Dose-response relationships were determined using log-logistic model for 50%, 80%, and 90% control rates at 1, 7 and 14 days after treatment (DAT) at 2–4, 6–8 and 10–12 leaf (L) growth stages. Flaming at early stage of weed growth (2–4 L) resulted in 90% control of all dicotyledon weeds at 14 DAT with propane doses ranging from 35.0 to 65.8kg ha-¹, while this range was from 28.6 to 54.9 kg ha-¹ at 80%, suggesting approximately 15–20% less propane use for 80% weed control compared to 90% control. Monocotyledon weeds were resistant to thermal stress even at 2–4 L stage and could be controlled at 14 DAT with propane dose from 125.7 to 210.9 kg ha-¹ at 90% control rate and 74.6 to 133.4 kg ha-¹ at 80% control rate. The cost of weedflaming was compared to the spraying application using partial budgeting method. Flaming costs (30.6 and 34.4 $ ha-¹) for dicotyledonweeds at 80% and 90% weed control rates were comparable to herbicide application at 2-4 L stage, whereas flaming was found costly than chemical spraying at other growth stages for any weed species.