Use of Preemergence Herbicides for Weed Control in Rye Grass Cover Crops between Watermelon Rows

Abstract

The objective of this study was to determine the effectiveness of preemergence herbicides between watermelon [Citrullus lanatus(Thunb.) Matsum. and Nak.] rows for weed control in rye (Secale cerealeL.) cover crops between rows. Preemergence herbicides tank mixed with paraquat were fomesafen at 0.23 and 0.72 kg/ha, flumioxazin 0.07 and 0.14 kg/ha, S-metolachlor at 0.11 and 0.17 kg/ha, and terbacil at 0.11, 0.17, and 0.43 kg/ha. At 10 and 18 d after application (DAA), a preemergence herbicide tank mixed with paraquat increased wild radish (Raphanus raphanistrumL.) control (0% = no control, 100% = complete control) compared to control with application of paraquat alone. S-metolachlor at 0.11 kg/ha provided reduced wild radish control at 10 and 18 DAA (70% and 66%, respectively) compared to all other preemergence herbicide treatments (83% to 100% and 84% to 96%, respectively). No injury from the preemergence herbicides was observed. Volunteer iron clay pea [Vigna unguiculata(L.) Walpers] emerged at 18 DAA and no differences in iron clay pea control were observed among treatments. The use of a 30.5-cm-wide weed-free strip beside the planting bed will allow farmers to apply posttransplant herbicide treatments later or further away from the planting bed.